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{{short description|Abstract strategy board game for two players}} | |||
{{Infobox_Game| | |||
{{About|the board game||Go (disambiguation)}} | |||
subject_name= Go | | |||
{{Infobox game | |||
image_link= ] | | |||
| title = Go | |||
image_caption= A traditional board for the game is wooden, with the lines painted on. The stones are flattened spheroids and fit closely together when placed on adjacent points. | | |||
| italic title = no | |||
players= 2 | | |||
| image_link = FloorGoban.JPG | |||
ages= Any | | |||
| image_size = 300px | |||
setup_time= No setup needed | | |||
| image_caption = Go is played on a grid (usually 19×19). Game pieces (''stones'') are placed on the grid line intersections. | |||
playing_time= 10 minutes to 3 hours,<br>although tournament games can last more than 16 hours | | |||
| years = 548 BCE (earliest record) to present | |||
complexity= Low | | |||
| genre = {{ubl|]|]|]}} | |||
strategy= Very High | | |||
| players = 2 | |||
random_chance= None | | |||
| setup_time = Minimal | |||
skills= ], Observation | | |||
| playing_time = {{ubl|Casual: 20–90 minutes|Professional: 1–6 hours or more{{ref label|note1|a}}}} | |||
footnotes = | |||
| random_chance = None | |||
| skills = ], ], ] | |||
| AKA = {{ubl|{{audio|Zh-wéiqí.ogg|Weiqi|help=no}}|{{transliteration|ja|Igo}}|{{transliteration|ko|Paduk}} / {{transliteration|ko|Baduk}}}} | |||
| footnotes = {{note label|note1|a}}Some professional games exceed 16 hours and are played in sessions spread over two days. | |||
}} | |||
{{Infobox Chinese | |||
| t = {{linktext|圍棋}} | |||
| s = {{linktext|围棋}} | |||
| l = 'encirclement board game' | |||
| p = wéiqí | |||
| w = {{tone superscript|wei2-ch}}{{wg-apos}}{{tone superscript|i2}} | |||
| mi = {{IPAc-cmn|AUD|Zh-wéiqí.ogg|wei|2|.|q|i|2}} | |||
| suz = wé-jí | |||
| j = wai4 kei4 | |||
| y = wàih-kèih | |||
| ci = {{IPAc-yue|w|ai|4|-|k|ei|4}} | |||
| poj = uî-kî | |||
| mc = hwigi | |||
| oc-bs = *{{IPA|ʷə (r)ə}} | |||
| oc-zz = *{{IPA|ɢʷɯl ɡɯ}} | |||
| kanji = {{linktext|囲碁}} or {{linktext|碁}} | |||
| hiragana = いご or ご | |||
| romaji = igo or go | |||
| hangul = 바둑 | |||
| rr = baduk | |||
| mr = paduk | |||
| tib = མིག་མངས | |||
| wylie = mig mangs | |||
| qn = cờ vây | |||
| hn = 碁圍 | |||
| tp = wéi-cí | |||
| bpmf = ㄨㄟˊ ㄑㄧˊ | |||
| katakana = イゴ or ゴ | |||
}} | }} | ||
'''Go''', also known as '''Wéiqí''' in ] ({{zh-t|圍棋}}; {{zh-s|围棋}}), and '''Baduk''' in ] (]:바둑), is a strategic, ] two-player ] originating in ancient ], before ]. The game is now popular throughout ] and on the Internet. The object of the game is to place stones so they control a larger board territory than one's opponent, while preventing them from being surrounded and captured by the opponent. | |||
# <!--Please do not add names in other languages or more kanji/hanzi/hangul or transliterations in the opening paragraph as the name of the game in Chinese, Japanese and Korean is given in the box on the side, beneath the info box.--> | |||
The English name ''Go'' originated from the ] pronunciation "go" of the ] 棋/碁; in Japanese the name is written 碁. The ] name Wéiqí roughly translates as "''encirclement chess''", the "''board game of surrounding''", or the "''enclosing game''". Its ancient Chinese name is 弈 ({{zh-p|yì}}). The writings 棋/碁 are variants, as seen in the Chinese ]. The game is known as 囲碁 (''igo'' or ''wigo'') in ]. | |||
'''Go''' is an ] ] for two players in which the aim is to fence off more territory than the opponent. The game was invented in ] more than 2,500 years ago and is believed to be the oldest board game continuously played to the present day.<ref>{{cite web|url=https://www.usgo-archive.org/brief-history-go|title=A Brief History of Go|publisher=American Go Association|access-date=March 23, 2017}}</ref><ref>{{Citation|first=Peter|last=Shotwell|title=The Game of Go: Speculations on its Origins and Symbolism in Ancient China|year=2008|publisher=American Go Association|url=http://www.usgo-archive.org/files/bh_library/originsofgo.pdf|archive-url=https://web.archive.org/web/20130516100351/http://www.usgo.org/files/bh_library/originsofgo.pdf|archive-date=May 16, 2013|url-status=live}}</ref><ref>{{cite web|url=https://gobase.org/reading/history/china/?sec=part-2|title=The Legends of the Sage Kings and Divination|publisher=GoBase.org|access-date=May 12, 2022}}</ref><ref>{{Cite web |title=A Brief History of Go {{!}} British Go Association |url=https://www.britgo.org/intro/history |access-date=2023-12-16 |website=www.britgo.org}}</ref><ref>{{Cite web |title=The Ancient Chinese Game of Go |url=http://www.china.org.cn/english/features/Archaeology/131298.htm |access-date=2023-12-16 |website=www.china.org.cn}}</ref> A 2016 survey by the ]'s 75 member nations found that there are over 46 million people worldwide who know how to play Go, and over 20 million current players, the majority of whom live in ].<ref>{{Cite web|url=http://www.intergofed.org/wp-content/uploads/2016/06/2016_Go_population_report.pdf|title=Go Population Survey|last=The International Go Federation|date=February 2016|website=intergofed.org|access-date=28 November 2018|archive-url=https://web.archive.org/web/20170517013354/http://www.intergofed.org/wp-content/uploads/2016/06/2016_Go_population_report.pdf|archive-date=17 May 2017|url-status=live}}</ref> | |||
== Overview of the game == | |||
The game of Go is played by alternately placing stones on a grid. The two players, black and white, engage to maximize the territory they control, seeking to surround large areas of the board with their stones, to entrap any opposing stones that invade these areas, and to protect their own stones from capture. | |||
The ] are called '']''. One player uses the white stones and the other black. The players take turns placing their stones on the vacant intersections (''points'') on the ]. Once placed, stones may not be moved, but ''captured stones'' are immediately removed from the board. A single stone (or connected group of stones) is ''captured'' when surrounded by the opponent's stones on all ] adjacent points.{{sfn|Iwamoto|1977|p=22}} The game proceeds until neither player wishes to make another move. | |||
The strategy involved can become very subtle and complex. Some high-level players spend years perfecting strategy. Go is considered by some to be the ultimate strategy game, superior in depth of complexity to ], ], and ]. | |||
When a game concludes, the winner is determined by counting each player's surrounded territory along with captured stones and ] (points added to the ] of the player with the white stones as compensation for playing second).{{sfn|Iwamoto|1977|p=18}} Games may also end by resignation.<ref name=":0" /> | |||
Go is typically classified as an ]. However, a resemblance between the game of Go and war is often suggested. The ] '']'', for instance, has sometimes been applied to Go strategy as well. On the other hand, general strategies of Go are well described by ] and are applied in other contexts such as management. | |||
The standard Go board has a 19×19 ] of lines, containing 361 points. Beginners often play on smaller 9×9 or 13×13 boards,{{sfn|Matthews|2004|p=1}} and archaeological evidence shows that the game was played in earlier centuries on a board with a 17×17 grid. Boards with a 19×19 grid had become standard, however, by the time the game reached ] in the 5th century ] and ] in the 7th century CE.{{sfn|Cho Chikun|1997|p=18}} | |||
Real wars end when the participants sign treaties. Likewise, in Go, the players have to agree that the game has ended. Only then are the score and the winner finally determined. | |||
Go was considered one of the ] of the cultured ] Chinese scholars in antiquity. The earliest written reference to the game is generally recognized as the historical annal '']''<ref name="The Tso Chuan book">{{cite book|last=Burton|first=Watson|title=The Tso Chuan|date=April 15, 1992|publisher=Columbia University Press |isbn=978-0-231-06715-7}}</ref>{{sfn|Fairbairn|1995|p={{page needed|date=May 2014}}}} ({{circa|4th century}} BCE).<ref name=chronology2>{{cite web|title=Warring States Project Chronology #2|publisher=University of Massachusetts Amherst|url=http://www.umass.edu/wsp/project/introductions/chronology2.html|access-date=2007-11-30|url-status=dead|archive-url=https://web.archive.org/web/20071219225436/http://www.umass.edu/wsp/project/introductions/chronology2.html|archive-date=2007-12-19}}</ref> | |||
==History== | |||
{{main|History of Go}} | |||
Despite its relatively ], Go is extremely complex. Compared to ], Go has both a larger board with more scope for play and longer games and, on average, many more alternatives to consider per move. The number of legal board positions in Go has been calculated to be approximately {{val|2.1e170}},<ref>{{cite web|url=https://tromp.github.io/go/gostate.pdf|last1=Tromp|first1=John|last2=Farnebäck|first2=Gunnar|title=Combinatorics of Go|website=tromp.github.io|date=January 31, 2016|access-date=June 17, 2020|archive-url=https://web.archive.org/web/20160125182938/https://tromp.github.io/go/gostate.pdf|archive-date=January 25, 2016|url-status=live}}</ref>{{efn|1=Game complexity can be difficult to estimate. The number of legal positions (]) for chess has been estimated at anywhere between 10<sup>43</sup> and 10<sup>50</sup>; in 2016 the number of legal positions for 19x19 Go was calculated by Tromp and Farneback at ~{{val|2.08e170}}. Alternately, a measure of all the alternatives to be considered at each stage of the game (]) can be estimated with ''b<sup>d</sup>'', where ''b'' is the game's breadth (number of legal moves per position) and ''d'' is its depth (number of moves or '']'' per game). For chess and Go the comparison is very rough, ~35<sup>80</sup> ≪ ~250<sup>150</sup>, or ~10<sup>123</sup> ≪ ~10<sup>360</sup>{{sfn|Allis|1994|pp=158–161, 171, 174|ps=, §§6.2.4, 6.3.9, 6.3.12}}}} which is far greater than the ], which is estimated to be on the order of 10<sup>80</sup>.<ref>{{cite book|last=Lee|first=Kai-Fu|author-link=Kai-Fu Lee|title=AI Superpowers: China, Silicon Valley, and the New World Order|date=September 25, 2018|publisher=]|isbn=9781328546395|access-date=June 17, 2020|url=https://books.google.com/books?id=Xb9wDwAAQBAJ}}</ref> | |||
] in the ].]] | |||
The origins of the game lie in ] and the earliest references come from China in the ] (], from '']''). Except for changes in the board size and starting position, Go has essentially kept the same rules since that time, which quite likely makes it the oldest board game still played today. | |||
{{GoBoardGame}} | |||
According to legend, the game was used as a ] tool after the ancient ] ] 堯 (2337 - 2258 BC) designed it for his son, Danzhu, who he thought needed to learn discipline, concentration, and balance. Another suggested genesis for the game states that in ancient times, Chinese warlords and generals would use pieces of stone to map out attacking positions. Further and more plausible theories relate Go equipment to ] or ]. | |||
==Names of the game== | |||
Before the industrial age in China, Go was long perceived as the popular game of the elite aristocratic class while ] (Chinese chess) was perceived as the game of the masses. Go was considered one of the cultivated arts of the ] (]), along with ], ] and playing the ], known as 琴棋書畫 (], ]: Sìyì), or the ]. | |||
The name ''Go'' is a short form of the Japanese word {{transliteration|ja|igo}} ({{lang|ja|囲碁}}; {{lang|ja|いご}}), which derives from earlier {{transliteration|ja|wigo}} ({{lang|ja|ゐご}}), in turn from ] {{transliteration|zh|{{IPA|ɦʉi gi}}}} ({{lang|zh|圍棋}}, ]: {{transliteration|zh|wéiqí}}, {{lit|encirclement board game|board game of surrounding}}). In English, the name ''Go'' when used for the game is often capitalized to differentiate it from the common word ].<ref>{{cite journal|last=Gao |first=Pat |title=Getting the Go-ahead |url=http://taiwanreview.nat.gov.tw/ct.asp?xItem=24319&CtNode=1360 |journal=Taiwan Review |year=2007 |volume=57 |page=55 |publisher=Kwang Hwa Publishing |location=Los Angeles, CA |url-status=dead |archive-url=https://web.archive.org/web/20120122131232/http://taiwanreview.nat.gov.tw/ct.asp?xItem=24319&CtNode=1360 |archive-date=2012-01-22}}</ref> In events sponsored by the ] Foundation, it is spelled ''goe''.<ref>See, e.g., {{cite web|url=https://www.eurogofed.org/egf/ing2005.htm|title=EGF Ing Grant Report 2004-2005|publisher=]|access-date=28 October 2017|archive-url=https://web.archive.org/web/20171028201540/https://www.eurogofed.org/egf/ing2005.htm|archive-date=28 October 2017|url-status=dead}}</ref> | |||
The Korean name {{transliteration|ko|baduk}} (바둑) derives from the ] word {{transliteration|ko|Badok}}, the origin of which is controversial; the more plausible etymologies include the suffix {{transliteration|ko|dok}} added to {{transliteration|ko|Ba}} to mean 'flat and wide board', or the joining of {{transliteration|ko|Bat}}, meaning 'field', and {{transliteration|ko|Dok}}, meaning 'stone'. Less plausible etymologies include a derivation of {{transliteration|ko|Badukdok}}, referring to the playing pieces of the game, or a derivation from Chinese {{transliteration|zh|páizi}} ({{lang|zh|排子}}), meaning 'to arrange pieces'.<ref>{{cite book |last=조 |first=항범 |date=October 8, 2005 |title=그런 우리말은 없다 |url=http://terms.naver.com/entry.nhn?docId=982836&cid=85&categoryId=2641 |publisher=태학사 |isbn=9788959660148 |access-date=June 3, 2014}}</ref> | |||
Go had reached Japan from China by the ], and gained popularity at the imperial court in the ]. By the beginning of the ], the game was played in the general public in Japan. | |||
== Overview == | |||
] playing Go while having his wounds attended to]] | |||
] | |||
Early in the ], the then best player in Japan, ], was made head of a newly founded Go academy (the ], the first of several competing schools founded about the same time), which developed the level of playing greatly, and introduced the ] style system of ranking players. The government discontinued its support for the Go academies in ] as a result of the fall of the ]. | |||
Go is an adversarial game between two players with the objective of capturing territory. That is, occupying and surrounding a larger total empty area of the board with one's stones than the opponent.{{sfn|Matthews|2004|p=2}} As the game progresses, the players place stones on the board creating stone "formations" and enclosing spaces. Stones are never moved on the board, but when "captured" are removed from the board. Stones are linked together into a formation by being adjacent along the black lines, not on diagonals (of which there are none). Contests between opposing formations are often extremely complex and may result in the expansion, reduction, or wholesale capture and loss of formations and their enclosed empty spaces (called "eyes"). Another essential component of the game is control of the ''sente'' (that is, controlling the offense, so that one's opponent is forced into defensive moves); this usually changes several times during play. | |||
In honour of the Honinbo school, whose players consistently dominated the other schools during their history, one of the most prestigious Japanese Go championships is called the "]" tournament. | |||
displays the four "liberties" (adjacent empty points) of a single black stone. Illustrations , , and show White reducing those liberties progressively by one. In , when Black has only one liberty left, that stone is under attack and about to be captured and eliminated (a state called ''atari'').{{sfn|Cobb|2002|p=12}} White may capture that stone (remove it from the board) with a play on its last liberty (at D-1).]] | |||
Historically, Go has been unequal in terms of ]. However, the opening of new, open tournaments and the rise of strong female players, most notably ], has in recent years legitimised the strength and competitiveness of emerging female players. | |||
Initially the board is bare, and players alternate turns to place one stone per turn. As the game proceeds, players try to link their stones together into "living" formations (meaning that they are permanently safe from capture), as well as threaten to capture their opponent's stones and formations. Stones have both offensive and defensive characteristics, depending on the situation. | |||
An essential concept is that a formation of stones must have, or be capable of making, at least two enclosed open points known as ] to preserve itself from being captured. A formation having at least two eyes cannot be captured, even after it is surrounded by the opponent on the outside,{{sfn|Iwamoto|1977|p=77}} because each eye constitutes a ] that must be filled by the opponent as the final step in capture. A formation having two or more eyes is said to be unconditionally ],{{sfn|Cho Chikun|1997|p=21}} so it can evade capture indefinitely, and a group that cannot form two eyes is said to be ''dead'' and can be captured. | |||
Around 2000, in ], the ] (Japanese comic) and ] series '']'' popularized Go among the youth and started a Go boom in Japan. In January 2004, the ''Hikaru no Go'' manga began running in the US (monthly) edition of '']''. Whether this will lead to a strong following in the US is yet to be seen. | |||
The general strategy is to place stones to fence-off territory, attack the opponent's weak groups (trying to kill them so they will be removed), and always stay mindful of the ] of one's own groups.{{sfn|Cho Chikun|1997|p=28}}{{sfn|Cobb|2002|p=21}} The liberties of groups are countable. Situations where mutually opposing groups must capture each other or die are called capturing races, or ].{{sfn|Cho Chikun|1997|p=69}} In a capturing race, the group with more liberties will ultimately be able to capture the opponent's stones.{{sfn|Cho Chikun|1997|p=69}}{{sfn|Cobb|2002|p=20}}{{efn|Eyes and other complications may need to be considered when counting liberties}} Capturing races and the elements of life or death are the primary challenges of Go. | |||
Scott A. Boorman's ''The Protracted Game: A Wei-Chi Interpretation of Maoist Revolutionary Strategy'' likens the game to historical events, saying that the ] were better at surrounding territory. | |||
{{-}} | |||
In the end game players may pass rather than place a stone if they think there are no further opportunities for profitable play.<ref>{{cite web|title=KGS Go Tutorial: Game End|url=https://www.gokgs.com/tutorial/gameEnd.jsp|publisher=KGS|access-date=5 June 2014}}</ref> The game ends when both players pass{{sfn|Cho Chikun|1997|p=35}} or when one player resigns. In general, to score the game, each player counts the number of unoccupied points surrounded by their stones and then subtracts the number of stones that were captured by the opponent. The player with the greater score (after adjusting for handicapping called ]) wins the game. | |||
==Nature of the game== | |||
Although rules of Go can be written so that they are very simple, the game strategy is extremely complex. Go is a ], ], ], putting it in the same class as ], ] (draughts), and ] (othello). It greatly exceeds draughts and reversi in depth and complexity, and transcends even the complexity of chess. Its large board and lack of restrictions allows great scope in strategy. Decisions in one part of the board may be influenced by an apparently unrelated situation in a distant part of the board. Plays made early in the game can shape the nature of conflict a hundred moves later. | |||
In the opening stages of the game, players typically establish groups of stones (or ''bases'') near the corners and around the sides of the board, usually starting on the third or fourth line in from the board edge rather than at the very edge of the board. The edges and corners make it easier to develop groups which have better options for ''life'' (self-viability for a group of stones that prevents capture) and establish formations for potential territory.{{sfn|Cho Chikun|1997|p=107}} Players usually start near the corners because establishing territory is easier with the aid of two edges of the board.{{sfn|Iwamoto|1977|p=93}} Established corner opening sequences are called ] and are often studied independently.{{sfn|Cho Chikun|1997|p=119}} However, in the mid-game, stone groups must also reach in towards the large central area of the board to capture more territory. | |||
The game emphasizes the importance of balance on multiple levels, and has internal tensions. To secure an area of the board, it is good to play moves close together; but to cover the largest area one needs to spread out. To ensure one does not fall behind, expansionist play is required; but playing too broadly leaves weaknesses undefended that can be exploited. Playing too ''low'' (close to the edge) secures insufficient territory and influence; yet playing too ''high'' (far from the edge) allows the opponent to invade. Many people find the game attractive for its reflection of the contradictary demands found in real life. Indeed, a common saying is "life is like Go". | |||
] are points that lie in between the boundary walls of black and white, and as such are considered to be of no value to either side. ] are mutually alive pairs of white and black groups where neither has two eyes. | |||
The ] of Go is such that even an introduction to strategy can fill a book, and many good introductory books are available. See ] for a very brief introduction to the main concepts of Go strategy. | |||
''Ko'' (Chinese and Japanese: {{lang|zh|劫}}) is a potentially indefinitely repeated stone-capture position. The rules do not allow a board position to be repeated. Therefore, any move which would restore the previous board position would not be allowed, and the next player would be forced to play somewhere else. If the play requires a strategic response by the first player, further changing the board, then the second player could "retake the ko," and the first player would be in the same situation of needing to change the board before trying to take the ko back. And so on. {{sfn|Cho Chikun|1997|p=33}} Some of these ''ko fights'' may be important and decide the life of a large group, while others may be worth just one or two points. Some ko fights are referred to as ''picnic kos'' when only one side has a lot to lose.{{sfn|Cho Chikun|1997|p=37}} In Japanese, it is called a '']'' ko.<ref>{{cite web|url=http://senseis.xmp.net/?HanamiKo |title=Hanami Ko at Sensei's Library |publisher=Senseis.xmp.net |date=2013-01-09 |access-date=2014-03-25}}</ref> | |||
It is commonly said that no game has ever been played twice. This may be true: On a 19×19 board, there are about 3<sup>361</sup>×0.012 = 2.1×10<sup>170</sup> possible positions, most of which are the end result of about (120!)<sup>2</sup> = 4.5×10<sup>397</sup> different (no-capture) games, for a total of about 9.3×10<sup>567</sup> games. Allowing captures gives as many as | |||
Playing with others usually requires a knowledge of each player's strength, indicated by the player's ] (increasing from 30 kyu to 1 kyu, then 1 dan to 7 dan, then 1 dan pro to 9 dan pro). A difference in rank may be compensated by a handicap—Black is allowed to place two or more stones on the board to compensate for White's greater strength.{{sfn|Iwamoto|1977|p=109}}{{sfn|Cho Chikun|1997|p=91}} There are different rulesets (Korean, Japanese, Chinese, AGA, etc.), which are almost entirely equivalent, except for certain special-case positions and the method of scoring at the end. | |||
:<math>10^{7.49 \times 10^{48}}</math> | |||
=== Basic concepts === | |||
, all of which last for over 4.1×10<sup>48</sup> moves! (For two comparisons: the number of legal positions in chess is estimated to be between 10<sup>43</sup> and 10<sup>50</sup>; and physicists estimate that there are not more than 10<sup>90</sup> protons in the entire visible universe.) | |||
{{more citations needed section|date=February 2016}} | |||
{{Main|Go terms}} | |||
Basic strategic aspects include the following: | |||
* Connection: Keeping one's own stones connected means that fewer groups need to make living shape, and one has fewer groups to defend. | |||
* Cut: Keeping opposing stones disconnected means that the opponent needs to defend and make living shape for more groups. | |||
* Stay alive: The simplest way to stay alive is to establish a foothold in the corner or along one of the sides. At a minimum, a group must have two eyes (separate open points) to be alive.<ref name=":0">{{Citation|last=Baker|first=Karl|title=The Way to Go: How to Play the Asian Game of Go|year=2008|orig-year=1986|url= http://www.usgo-archive.org/files/pdf/W2Go4E-book.pdf|edition=7th|publisher=American Go Association|location=New York, NY|archive-url=https://web.archive.org/web/20121203014424/http://www.usgo.org/files/pdf/W2Go4E-book.pdf|archive-date=December 3, 2012|url-status=live}}</ref> An opponent cannot fill in either eye, as any such move is suicidal and prohibited in the rules. | |||
* Mutual life (seki) is better than dying: A situation in which neither player can play on a particular point without then allowing the other player to play at another point to capture. The most common example is that of adjacent groups that share their last few liberties—if either player plays in the shared liberties, they can reduce their own group to a single liberty (putting themselves in ''atari''), allowing their opponent to capture it on the next move. | |||
* Death: A group that lacks living shape is eventually removed from the board as captured. | |||
* Invasion: Set up a new living group inside an area where the opponent has greater influence, means one reduces the opponent's score in proportion to the area one occupies. | |||
* Reduction: Placing a stone far enough into the opponent's area of influence to reduce the amount of territory they eventually get, but not so far that it can be cut off from friendly stones outside. | |||
* Sente: A play that forces one's opponent to respond (]). A player who can regularly play ''sente'' has the initiative and can control the flow of the game. | |||
* Sacrifice: Allowing a group to die in order to carry out a play, or plan, in a more important area. | |||
The strategy involved can become very abstract and complex. High-level players spend years improving their understanding of strategy, and a novice may play many hundreds of games against opponents before being able to win regularly. | |||
== Traditional equipment == | |||
] | |||
{{main|Go equipment}} | |||
== Strategy == | |||
Although one could play Go with a piece of cardboard for a board and a bag of plastic tokens, many Go players pride themselves on their game sets. | |||
{{Main|Go strategy and tactics}} | |||
Strategy deals with global influence, the interaction between distant stones, keeping the whole board in mind during local fights, and other issues that involve the overall game. It is therefore possible to allow a tactical loss when it confers a strategic advantage. | |||
The traditional Go board (called a ''goban'' in Japanese) is solid wood, from 10–18 cm thick, and often stands on its own attached legs. It is preferably made from the rare golden-tinged ] tree (''Torreya nucifera''), with the very best made from Kaya trees up to 700 years old. More recently, the ] (''Torreya californica'') has been prized for its light color and pale rings. | |||
Other woods often used to make quality table boards include ] (''Thujopsis dolabrata''), ] (''Cercidiphyllum japonicum''), and ] (''Agathis''). | |||
Novices often start by randomly placing stones on the board, as if it were a game of chance. An understanding of how stones connect for greater power develops, and then a few basic ] may be understood. Learning the ways of life and death helps in a fundamental way to develop one's strategic understanding of ''weak groups''.{{efn|1=Whether or not a group is weak or strong refers to the ease with which it can be killed or made to live. See this by Benjamin Teuber, amateur 6 dan, for some views on how important this is felt to be.}} A player who both plays aggressively and can handle adversity is said to display ], or fighting spirit, in the game. | |||
Players sit on reed mats ('']'') on the floor to play. The stones (''go-ishi'') are kept in matching solid wood pots (''go-ke'') and are made out of ]shell (white) and ] (black) and are extremely smooth. The classic slate is from the nachiguro slate mined in ] and the clamshell from the Hamaguri clam. The natural resources of Japan have been unable to keep up with the enormous demand for the native clams and slow-growing Kaya trees; both must be of sufficient age to grow to the desired size, and they are now extremely rare at the age and quality required, raising the price of such equipment tremendously. | |||
=== Opening strategy === | |||
In clubs and at tournaments, where large numbers of sets must be maintained (and usually purchased) by one organization, the expensive traditional sets are not usually used. For these situations, table boards (of the same design as floor boards, but only about 2–5 cm thick and without legs) are used, and the stones are made of glass rather than slate and shell. Bowls will often be plastic if wooden bowls are not available. ] stones could be used, but are considered inferior to ] as they are generally much lighter, and most players find that not even the lower price justifies their unpleasantness. | |||
{{main|Go opening}} | |||
Traditionally, the board's grid is 1.5 ] long by 1.4 shaku wide (455 mm by 424 mm) with space beyond to allow stones to be played on the edges and corners of the grid. This often surprises newcomers: it is not a perfect square, but is longer than it is wide, in the proportion 15:14. Two reasons are frequently given for this. One is that when the players sit at the board, the angle at which they view the board gives a foreshortening of the grid; the board is slightly longer between the players to compensate for this. Another suggested reason is that the Japanese ] finds structures with geometric symmetry to be in bad taste. | |||
In the opening of the game, players usually play and gain territory in the corners of the board first, as the presence of two edges makes it easier for them to surround territory and establish the eyes they need.{{sfn|Ishigure|2006|pp=7–8}} From a secure position in a corner, it is possible to lay claim to more territory by extending along the side of the board.{{sfn|Otake|2002|p=2}} The opening is the most theoretically difficult part of the game and takes a large proportion of professional players' thinking time.{{sfn|Ishigure|2006|p=6}}{{sfn|Kageyama|2007|p=153}} The first stone played at a corner of the board is generally placed on the third or fourth line from the edge. Players tend to play on or near the 4–4 star point during the opening. Playing nearer to the edge does not produce enough territory to be efficient, and playing further from the edge does not safely secure the territory.{{sfn|Nihon Kiin|1973|p=7 (Vol. 2)}} | |||
Traditional stones are made so that black stones are slightly larger in diameter than white; this is probably to compensate for the optical illusion created by contrasting colours that would make equal-sized white stones appear larger on the board than black stones. The difference is slight, and since its effect is to make the stones appear the same size on the board, it can be surprising to discover they are not. | |||
In the opening, players often play established sequences called ], which are locally balanced exchanges;<ref name=Joseki>{{citation | last = Ishida | first = Yoshio | title = Dictionary of Basic Joseki| year = 1977 | publisher = Kiseido Publishing Company}}</ref> however, the joseki chosen should also produce a satisfactory result on a global scale. It is generally advisable to keep a balance between territory and influence. Which of these gets precedence is often a matter of individual taste. | |||
The bowls for the stones are of a simple shape, like a flattened sphere with a level underside. | |||
The lid is loose-fitting and is upturned before play as a tray to collect stones captured during the game. The bowls are usually made of turned wood, although small lidded baskets of woven bamboo or reeds make an attractive cheaper alternative. | |||
=== Middlegame and endgame === | |||
The traditional manner to place a Go stone is to hold it between the tips of the outstretched index and middle fingers and then strike the board firmly to create a sharp click. Many consider the ] properties of the wood of the board to be quite important. The traditional ''goban'' will usually have its underside carved with a pyramid called a ''heso'' recessed into the board. Tradition holds that this is to give a better resonance to the stone's click, but the more conventional explanation is to allow the board to expand and contract without splitting the wood. A board is seen as more attractive when it is marked with slight dents from decades (or centuries) of stones striking the surface. | |||
The middle phase of the game is the most combative, and usually lasts for more than 100 moves. During the middlegame, the players invade each other's territories, and attack formations that lack the necessary ''two eyes'' for viability. Such groups may be saved or sacrificed for something more significant on the board.<ref name="Think Big in Go">{{cite web|last1=David|first1=Ormerod|title=Thinking big in Go|url=http://gogameguru.com/thinking-big/|publisher=GoGameGuru|access-date=5 June 2014}}</ref> It is possible that one player may succeed in capturing a large weak group of the opponent's, which often proves decisive and ends the game by a resignation. However, matters may be more complex yet, with major trade-offs, apparently dead groups reviving, and skillful play to attack in such a way as to construct territories rather than kill.<ref name="Induction in Go">{{cite web|last1=David|first1=Ormerod|title=Go technique: Induction in the game of Go|url=http://gogameguru.com/go-technique-induction/|publisher=GoGameGuru|access-date=5 June 2014}}</ref> | |||
The end of the middlegame and transition to the endgame is marked by a few features. Near the end of a game, play becomes divided into localized fights that do not affect each other,{{sfn|Müller|Gasser|1996|p=273}} with the exception of ''ko'' fights, where before the central area of the board related to all parts of it. No large weak groups are still in serious danger. Moves can reasonably be attributed some definite value, such as 20 points or fewer, rather than simply being necessary to compete. Both players set limited objectives in their plans, in making or destroying territory, capturing or saving stones. These changing aspects of the game usually occur at much the same time, for strong players. In brief, the middlegame switches into the endgame when the concepts of strategy and influence need reassessment in terms of concrete final results on the board. | |||
== Rules == | == Rules == | ||
{{ |
{{Main|Rules of Go}} | ||
Aside from the order of play (alternating moves, Black moves first or takes a handicap) and scoring rules, there are essentially only two rules in Go: | |||
] | |||
* '''Liberty rule''' states that ''every stone remaining on the board must have at least one open point (a ''liberty'') directly orthogonally adjacent (up, down, left, or right)'', '''or''' ''must be part of a connected group that has at least one such open point (liberty) next to it. Stones or groups of stones which lose their last liberty are removed from the board.'' | |||
* '''Repetition Rule''' (]) states that ''a stone on the board must never immediately repeat a previous position of a captured stone, thus only a move elsewhere on the board is permitted that turn.'' Since without this rule such a pattern of the two players repeating their prior moves (capturing stones in same places) could continue indefinitely, this rule prevents a stalemate. | |||
Almost all other information about how the game is played is heuristic, meaning it is learned information about how the patterns of the stones on the board function, rather than a rule. Other rules are specialized, as they come about through different rulesets, but the above two rules cover almost all of any played game. | |||
Although there are some minor differences between rulesets used in different countries,<ref name=RulesComparison>{{Citation | url = https://www.britgo.org/rules/compare.html | title = Comparison of some go rules | author = British Go Association | access-date = 2007-12-20}}</ref> most notably in Chinese and Japanese scoring rules,<ref>{{Citation | url=http://nrich.maths.org/public/viewer.php?obj_id=1470 | publisher = University of Cambridge | author = NRICH Team | title = Going First | access-date = 2007-06-16}}</ref> these differences do not greatly affect the tactics and strategy of the game. | |||
Except where noted, the basic rules presented here are valid independent of the scoring rules used. The scoring rules are explained separately. ] for which there is no ready English equivalent are commonly called by their Japanese names. | |||
=== Basic rules === | === Basic rules === | ||
] | |||
] | |||
The two players, Black and White, take turns placing stones of their color on the intersections of the board, one stone at a time. The usual board size is a 19×19 grid, but for beginners or for playing quick games,{{sfn|Kim|Jeong|1997|pp=3–4}} the smaller board sizes of 13×13{{sfn|Nihon Kiin|1973|p=22 (Vol. 1)}} and 9×9 are also popular.{{sfn|Moskowitz|2013|p=14}} | |||
The board is empty to begin with.{{sfn|Lasker|1960|p=2}} Black plays first unless given a handicap of two or more stones, in which case White plays first. The players may choose any unoccupied intersection to play on except for those forbidden by the ] and ] rules (see below). Once played, a stone can never be moved and can be taken off the board only if it is ].{{sfn|Nihon Kiin|1973|p=23 (Vol. 1)}} A player may pass their turn, declining to place a stone, though this is usually only done at the end of the game when both players believe nothing more can be accomplished with further play. When both players pass consecutively, the game ends{{sfn|Fairbairn|2004|p=12}} and is then ]. | |||
===Liberties and capture=== | |||
* Two players, ''black'' and ''white'', take turns placing a ''stone'' (game piece) on the ''points'' (intersections) of a 19 by 19 ''board'' (grid). Black moves first. | |||
] | |||
* Stones must have ''liberties'' (empty adjacent points) to remain on the board. Stones connected by lines are called ''chains'', and share their liberties. | |||
Vertically and horizontally adjacent stones of the same color form a chain (also called a ''string'' or ''group''),{{sfn|Fairbairn|2004|p=7}} forming a discrete unit that cannot then be divided.<ref>{{citation | url = http://nrich.maths.org/public/viewer.php?obj_id=1433 | title = Behind the Rules of Go | last = Matthews | first = Charles | publisher = University of Cambridge | access-date = 2008-06-09}}</ref> Only stones connected to one another by the lines on the board create a chain; stones that are diagonally adjacent are not connected. Chains may be expanded by placing additional stones on adjacent intersections, and they can be connected together by placing a stone on an intersection that is adjacent to two or more chains of the same color.<ref name="Go Board Game pdf">{{cite web|title=Go The Board Game|url=http://kopoint.files.wordpress.com/2012/12/go-the-game.pdf|access-date=20 August 2014|archive-url=https://web.archive.org/web/20130725124759/http://kopoint.files.wordpress.com/2012/12/go-the-game.pdf|archive-date=25 July 2013|url-status=dead}}</ref> | |||
* When a stone or a chain of stones is surrounded by opponent stones, so that it has no more liberties, it is ''captured'' and removed from the board. | |||
* If a stone has no liberties as soon as it is played, but simultaneously removes the last liberty from one or more of the opponent's chains, the opponent's chains are captured and the played stone is not. | |||
* '']'': A stone cannot be played on a particular point if doing so would recreate the board position that existed after the same player's previous turn. | |||
* A player may ''pass'' instead of placing a stone. When both players pass consecutively, the game ends and is then ]. | |||
A vacant point adjacent to a stone, along one of the grid lines of the board, is called a ''liberty'' for that stone.{{sfn|Kim|Jeong|1997|p=12}}{{sfn|Fairbairn|2004|p=6}} Stones in a chain share their liberties.{{sfn|Fairbairn|2004|p=7}} A chain of stones must have at least one liberty to remain on the board. When a chain is surrounded by opposing stones so that it has no liberties, it is captured and removed from the board.{{sfn|Dahl|2001|p=206}} | |||
A player's score is the number of empty points enclosed only by his stones plus the number of points occupied by his stones. The player with the higher score wins. (Note that there are other rulesets that count the score differently, yet almost always produce the same result.) For a more detailed treatment, see ]. | |||
{{clear}} | |||
This is the essence of the game of Go. The risk of capture means that stones must work together to control territory, which makes the gameplay very complex and interesting. (Also see ].) | |||
=== Ko rule === | |||
Go allows one to play not only ''even games'' (games between players of roughly equal strength) but also ''handicap games'' (games between players of unequal strength); see ]. | |||
{{main|Ko fight}} | |||
] (black) at the end of the opening stage; white has developed a great deal of potential territory, while black has emphasized central influence.]] | |||
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{{Go board 5x5 | |||
| ul| u| u| u| ur | |||
| l| b| w| | r | |||
| b| c| b1| w| r | |||
| l| b| w| | r | |||
| dl| d| d| d| dr|32}} | |||
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=== Optional rules === | |||
An example of a situation in which the ko rule applies | |||
Optional Go rules may set the following: | |||
</div> | |||
* compensation points, almost always for the second player, see '']''; | |||
</div> | |||
* compensation stones placed on the board before alternate play, allowing players of different strengths to play interesting games (see ] for more information). | |||
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Players are not allowed to make a move that returns the game to the immediately prior position. This rule, called the ], prevents unending repetition (a stalemate).{{sfn|Kim|Jeong|1997|pp=48–49}} As shown in the example pictured: White had a stone where the red circle was, and Black has just captured it by playing a stone at '''1''' (so the White stone has been removed). However, it is readily apparent that now Black's stone at '''1''' is immediately threatened by the three surrounding White stones. If White were allowed to play again on the red circle, it would return the situation to the original one, but the ''ko'' rule forbids that kind of endless repetition. Thus, White is forced to move elsewhere, or pass. If White wants to recapture Black's stone at '''1''', White must attack Black somewhere else on the board so forcefully that Black moves elsewhere to counter that, giving White that chance. If White's forcing move is successful, it is termed "gaining the ''sente''"; if Black responds elsewhere on the board, then White can retake Black's stone at '''1''', and the ''ko'' continues, but this time Black must move elsewhere. A repetition of such exchanges is called a ''ko fight''.{{sfn|Kim|Jeong|1997|pp=144–147}} To stop the potential for ''ko fights'', two stones of the same color would need to be added to the group, making either a group of 5 Black or 5 White stones. | |||
While the various rulesets agree on the ko rule prohibiting returning the board to an ''immediately'' previous position, they deal in different ways with the relatively uncommon situation in which a player might recreate a past position that is further removed. See {{section link|Rules of Go|Repetition}} for further information. | |||
== Strategy == | |||
{{main|Go strategy and tactics}} | |||
Basic strategic aspects include the following: | |||
* Connection: Keeping one's own stones connected means that fewer groups need defense. | |||
* Cut: Keeping opposing stones disconnected means that the opponent needs to defend more groups. | |||
* Life: This is the ability of stones to permanently avoid capture. The simplest way is for the group to surround two "eyes" (separate empty areas), so that filling one eye will not kill the group and is therefore suicidal. | |||
* Death: The absence of life, resulting in the removal of a group. | |||
*Invasion: Penetration into an opponents claimed territory as a means of swaying the balance of territory. | |||
== |
=== Suicide === | ||
] website , {{webarchive|url=https://web.archive.org/web/20130112214116/http://www.usgo.org/files/pdf/IngRules2006.pdf|date=12 January 2013}}, retrieved 5 August 2012</ref> and New Zealand rules,<ref name="AGA_rules">{{Cite web|title=The Rules of Go |website=American Go Association|url=https://www.usgo-archive.org/rules-of-go|access-date=5 August 2012|archive-url=https://web.archive.org/web/20120711140721/http://www.usgo.org/rules-go|archive-date=11 July 2012}}</ref> White may play A, a suicide stone that kills itself and the two neighboring white stones, leaving an empty three-space eye. Black naturally answers by playing at A, creating two eyes to live.]] | |||
Go is deep, as playing against any stronger player will demonstrate (] as established by ]). With each new level (rank) comes a deeper appreciation for the subtlety involved, and for the insight of stronger players. Beginners often start by randomly placing stones on the board, as if it were a game of chance — and they inevitably lose to experienced players. But soon an understanding of how stones connect to form strength develops, and shortly afterward a few basic ] may be understood. Learning the ways of ] helps to develop one's situational judgement. | |||
A player may not place a stone such that it or its group immediately has no liberties unless doing so immediately deprives an enemy group of its final liberty. In the second case, the enemy group is captured, leaving the new stone with at least one liberty, so the new stone can be placed.{{sfn|Kim|Jeong|1997|p=30}} This rule is responsible for the all-important difference between one and two eyes: if a group with only one eye is fully surrounded on the outside, it can be killed with a stone placed in its single eye. (An ] is an empty point or group of points surrounded by a group of stones). | |||
Further experience yields an understanding of the board, the importance of the edges, then the efficiency of developing (in the corners first, then sides, then centre). Soon, the advanced beginner understands that territory and influence are somewhat interchangeable — but there needs to be a balance. Best is to develop more or less at the same pace as the opponent, in both territory and influence. This intricate struggle of power and control makes the game highly dynamic. | |||
The ] and New Zealand rules do not have this rule,<ref name="Suicide in different rules.">{{cite web|title=Comparison of Some Go Rules|url=https://www.britgo.org/rules/compare.html|publisher=British Go Association|access-date=15 May 2014}}</ref> and there a player might destroy one of its own groups (commit suicide). This play would only be useful in limited sets of situations involving a small interior space or planning.{{sfn|Kim|Jeong|1997|p=28}} In the example at right, it may be useful as a ]. | |||
== Computers and Go == | |||
{{main|Computer Go}} | |||
=== Komi === | |||
Although much effort has gone in to programming ]s to play Go, even the strongest programs are no better than an average club player, and would easily be beaten by a strong player even getting a nine-stone handicap. Strong players have even beaten computer programs at handicaps of twenty-five stones. Of course, strong players do not currently have much interest in computer Go programs as opponents, as they do not yet play well enough. This is attributed to many qualities of the game, including the "]" nature of the victory condition, the large number of legal moves, the large board size, the nonlocal nature of the Ko rule, and the high degree of pattern recognition involved. On the other hand, a ]-playing computer, ], beat the world champion in ]. For this reason, many in the field of ] consider Go to be a better measure of a computer's capacity for thought than ]. | |||
{{Main|Komi (Go)}} | |||
Because Black has the advantage of playing the first move, the idea of awarding White some compensation came into being during the 20th century. This is called ], which gives white a 5.5-point compensation under Japanese rules, 6.5-point under Korean rules, and 15/4 stones, or 7.5-point under Chinese rules (number of points varies by rule set).<ref name="Komi Change">{{cite web|title=A change in Komi|url=http://www.usgo.org/aga-memo-regarding-komi|access-date=31 May 2014|url-status=dead|archive-url=https://web.archive.org/web/20221229064855/http://www.usgo.org/aga-memo-regarding-komi|archive-date=29 December 2022}}</ref> Under handicap play, White receives only a 0.5-point komi, to break a possible tie (''jigo''). | |||
=== Scoring rules === | |||
On the other hand, none of these factors prevents computers from playing far better than human players in certain endgame situations, exactly as in the case of chess. In chess, this is due to the use of end game ]s; in Go, to an application of the kind of game analysis pioneered by ], who invented ]s to analyze games and Go endgames in particular, an idea much further developed in application to Go by ] and ]. It is outlined in their book, ''Mathematical Go'' (ISBN 1568810326). While not of general utility in most play, it greatly aids the analysis of certain classes of positions. | |||
] | |||
Two general types of scoring procedures are used, and players determine which to use before play. Both procedures almost always give the same winner. | |||
Use of computer networks to allow humans to meet, discuss games, and play one another, is becoming very common, with many strong players regularly playing online. See ''Additional Resources'' below for more information. | |||
* '''Area scoring procedure (including Chinese):''' counts the number of points a player's stones occupy and surround. It is associated with contemporary Chinese play and was probably established there during the ] in the 15th or 16th century.<ref>{{cite web|work=New in Go|title=The rules debate as seen from Ancient China|last=Fairbairn|first=John|date=June 2006|publisher=Games of Go on Disc (GoGoD)|url=http://www.gogod.co.uk/NewInGo/C&IP.htm|access-date=2007-11-27|url-status=dead|archive-url=https://web.archive.org/web/20130112213532/http://www.gogod.co.uk/NewInGo/C%26IP.htm|archive-date=2013-01-12}}</ref> Beginner-friendly, but takes longer to count. A player's score is the number of stones that the player has on the board, plus the number of empty intersections surrounded by that player's stones. If there is disagreement about which stones are dead, then under area scoring rules, the players simply resume play to resolve the matter. The score is computed using the position after the next time the players pass consecutively. | |||
==Other board games sometimes compared with Go== | |||
* '''Territory scoring procedure (including Japanese and Korean):''' counts the number of empty points a player's stones surround, together with the number of stones the player captured. In the course of the game, each player retains the stones they capture, termed ''prisoners''. Any dead stones removed at the end of the game become prisoners. The score is the number of empty points enclosed by a player's stones, plus the number of prisoners captured by that player.{{efn|1=Exceptionally, in Japanese and Korean rules, empty points, even those surrounded by stones of a single color, may count as neutral territory if some of them are alive by seki. See the section below on ].}} Under territory scoring there can be an extra penalty for playing inside ones' territory, so if there is a disagreement extra play to resolve it would, in tournament settings, happen on a separate board, where the player claiming a group is dead would play first, and would demonstrate how to capture those stones. For further information, see ]. | |||
This is a list of some games that are played with similar equipment or come from the same area. | |||
Both procedures are counted after both players have passed consecutively, the stones that are still on the board but unable to avoid capture, called ''dead'' stones, are removed. Given that the number of stones a player has on the board is directly related to the number of prisoners their opponent has taken, the resulting net score, that is, the difference between Black's and White's scores is identical under both rulesets (unless the players have passed different numbers of times during the course of the game). Thus, the net result given by the two scoring systems rarely differs by more than a point.<ref>{{Citation | url = https://www.cs.cmu.edu/~wjh/go/rules/AGA.commentary.html | title = Demonstration of the Relationship of Area and Territory Scoring | first = Fred | last = Hansen | publisher = American Go Association | access-date = 2008-06-16}}</ref> | |||
* Variations of chess | |||
** ] (Western): This game dominates Western game culture; its history in the culture stretches back many centuries. | |||
** ]: A cross between Go and Chess. In this game the pieces have the same movements as the Queen in Chess. After a player moves, the piece fires an arrow (that has the same movement as a Queen in Chess). An arrow blocks the paths of other pieces and arrows. The player who can move last wins. There can never be a draw. | |||
** ]: This is the Korean variant of Chess, usually called "Korean Chess". It is also very different from Go in game play. Go and Janggi are the two main board games played in Korea. | |||
** ] 将棋: Early Western literature often referred to Go as "Japanese Chess". The Japanese do have their own game called Shogi; it is much more similar to the other Chess variants than to Go. Shogi schools were founded in Japan about the same time as Go schools, and the game held more players throughout history than Go did. But Shogi is considered "lower class" compared with Go. Until recently, professional Go players in Japan often played Shogi as amateur and vice versa, but this habit has decreased because they now have no time to play other games. | |||
** ] 象棋: This is the Chinese variant of Chess, usually called "Chinese chess" by English speakers. Like most Chess variants, it has great depth of strategy, but bears few similarities to Go in game play. Xiangqi, like Go, is played on points rather than squares. | |||
* Connection games. These are the most similar to Go in terms of style and strategy. One significant difference between Go and many connection games is the number of goals. In Hex, for example, there is only one goal: to connect your two sides. While this leads to significant strategic complexity (especially as the board size increases), in Go there are usually numerous different battles going on simultaneously. | |||
** ] and ] are connection games. Like Go, these have cutting and connecting tactics, but Hex is played on a hexagonal lattice. Mathematician ] independently invented a version of this game while at ], called Nash, in response to Go. | |||
** ], ], and ] are connection games similar to Hex, but of more depth. | |||
*Played on a Go board | |||
** ]: Played with the same equipment as Go (a 19x19 grid, black and white stones), in these games the goal is to create six stones in a row. | |||
** ], ] and ]: Played with the same equipment as Go (a 19x19 grid, black and white stones), in these games the goal is to create five stones in a row. The game style is thus much shorter and involves less strategy than Go. | |||
** ]: Played with a Go board restricted to 15x19 grid, and black and white stones. The goal is to get the football (the white stone) across the respective goal line. | |||
*Other similar-looking games | |||
** ] is a board game with black and white marbles. Strategy is somewhat of a cross between Reversi and Sumo wrestling, the goal being to push the other player's marbles off the playing surface. | |||
** ] is a Go-like game restricted to a single spatial ]. | |||
** ]: Marketed by ] as "Othello", Reversi bears superficial similarity to Go, with black and white circular pieces, an undifferentiated grid for a board, simple rules, and a goal of covering more of the board than the opponent. The game play is quite unlike Go, however, as it is based on flanking the opponent's pieces for capture. Captured pieces change their color. | |||
== |
=== Life and death === | ||
{{See also|Life and death}} | |||
] | |||
While not actually mentioned in the rules of Go (at least in simpler rule sets, such as those of New Zealand and the U.S.), the concept of a ''living'' group of stones is necessary for a practical understanding of the game.{{sfn|Matthews|2002|p={{page needed|date=May 2014}}}} | |||
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Go has been mentioned in many novels and short stories published in the Orient, and occasionally turns up in Western media as well. | |||
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{{Goban 9x9 | |||
|ulc| b| b| w| u| w| b| uc| b | |||
| b| c| b| w| | w| b| b| rc | |||
| b| b| w| w| | w| w| b| b | |||
| w| w| w| | | | w| b| rc | |||
| l| | | | | | w| b| b | |||
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| b| w| w| w| w| | w| b| b | |||
| lA| b| b| b| w| | w| b| rc | |||
| b| b| dc| b| w| d| w| b| b|22}} | |||
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In ], ]-winning author ] published '']'', a short novel based upon an epic game that took place over the course of several months in ]. An English translation appeared in ], around the time of Kawabata's death. Go also features (as "Wéi-chí") as a favourite pastime of and philosophical inspiration for the archvillan Howard Devore in the ] novels by ]. | |||
Examples of eyes (marked). The black groups at the top of the board are alive, as they have at least two eyes. The black groups at the bottom are dead as they only have one eye. The point marked ''a'' is a false eye, thus the black group with false eye ''a'' can be killed by white in two turns. | |||
</div> | |||
</div> | |||
</div> | |||
When a group of stones is mostly surrounded and has no options to connect with friendly stones elsewhere, the status of the group is either alive, dead or ''unsettled''. A group of stones is said to be alive if it cannot be captured, even if the opponent is allowed to move first. Conversely, a group of stones is said to be dead if it cannot avoid capture, even if the owner of the group is allowed the first move. Otherwise, the group is said to be unsettled: the defending player can make it alive or the opponent can ''kill'' it, depending on who gets to play first.{{sfn|Matthews|2002|p={{page needed|date=May 2014}}}} | |||
Go is featured in the cold war thriller, ''Shibumi'' by ]. The central character spends his adolescence studying the game under a master, and the major chapters of the book reflect Go strategies. | |||
An ] is an empty point or group of points surrounded by a group of stones. If the eye is surrounded by Black stones, White cannot play there unless such a play would take Black's last liberty and capture the Black stones. (Such a move is forbidden according to the suicide rule in most rule sets, but even if not forbidden, such a move would be a useless suicide of a White stone.) | |||
Shan Sa, a Chinese writer who lives in France, wrote ''La Joueuse de Go'', where a Chinese girl plays Go with a Japanese soldier and wins, although they are both extremely strong players. | |||
If a Black group has two eyes, White can never capture it because White cannot remove both liberties simultaneously. If Black has only one eye, White can capture the Black group by playing in the single eye, removing Black's last liberty. Such a move is not suicide because the Black stones are removed first. In the "Examples of eyes" diagram, all the circled points are eyes. The two black groups in the upper corners are alive, as both have at least two eyes. The groups in the lower corners are dead, as both have only one eye. The group in the lower left may seem to have two eyes, but the surrounded empty point marked ''a'' is not actually an eye. White can play there and take a black stone. Such a point is often called a ''false eye''.{{sfn|Matthews|2002|p={{page needed|date=May 2014}}}} | |||
Go is featured in Scarlett Thomas's book ''PopCo''. Alice Butler, the main character, works for a giant toy company where games of Go are encouraged to spark creativity. | |||
=== Seki (mutual life) === | |||
The world of the fantasy series ] has a similar game, called Stones, with a hexagonal base shape instead of square. | |||
] | |||
<!-- DEPRECATED as too complex. | |||
In the ] book ] by ], Go is played by the two protagonists when they are stuck in an ice tempest. | |||
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{{Goban 9x9 | |||
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| w| w| w| b| b| | b| | b | |||
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| lc| c| b| w| w| w| w| w| b | |||
| w| w| w| b| w| | w| b| b | |||
| b| b| b| b| w| w| w| b| r | |||
| dl| b| d| b| w| d| w| b| b|22}} | |||
<div class="thumbcaption" style="font-size: 88%;"> | |||
The book by Troy Anderson likens the game to a rosetta stone for understanding the underpinnings of strategy, especially for business. | |||
Example of seki (mutual life). Neither Black nor White can play on the marked points without reducing their own liberties for those groups to one (self-atari). | |||
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– Above deprecated. --> | |||
There is an exception to the requirement that a group must have two eyes to be alive, a situation called ''seki'' (or ''mutual life''). Where different colored groups are adjacent and share liberties, the situation may reach a position when neither player wants to move first because doing so would allow the opponent to capture; in such situations therefore both players' stones remain on the board (in seki). Neither player receives any points for those groups, but at least those groups themselves remain living, as opposed to being captured.{{efn|1=In game theoretical terms, seki positions are an example of a ].}} | |||
Seki can occur in many ways. The simplest are: | |||
In the webcomic ], the two main characters are occasionally seen discussing various subjects over a game of Go. | |||
# each player has a group without eyes and they share two liberties, and | |||
# each player has a group with one eye and they share one more liberty. | |||
In the "Example of seki (mutual life)" diagram, the two circled points are liberties shared by both a black and a white group. Both of these interior groups are at risk, and neither player wants to play on a circled point, because doing so would allow the opponent to capture their group on the next move. The outer groups in this example, both black and white, are alive. Seki can result from an attempt by one player to invade and kill a nearly settled group of the other player.{{sfn|Matthews|2002|p={{page needed|date=May 2014}}}} | |||
== Tactics == | |||
The game of Go plays a part in the ] TV ], '']'' which references a piece of computer technology called a "Go chip." Go figures prominently in the introduction of '']'' to the mysterious character of Jurgen during an important character arc in the television series La Femme Nikita. The game also appeared in an episode of '']'' entitled "The Cogenitor" in which it was revealed that ] plays the game. In another ] show, '']'', Dylan Hunt and Gaheris Rhade both play a futuristic version of the game, apparently on three boards at once. During episode 15 of season 3 of the television show '']'', several scenes took place in an underground Chinese Go club uncharacteristically populated by beautiful women. The characters even called it a "Go club". A 1980s TV series called ''Chessgame'' starred ] as a spy master who would spend long periods studying a Go board. | |||
{{Main|Go strategy and tactics}} | |||
''Tactics'' deal with immediate fighting between stones, capturing and saving stones, life, death and other issues localized to a specific part of the board. Larger issues which encompass the territory of the entire board and planning stone-group connections are referred to as ''Strategy'' and are covered in the ''Strategy'' section above. | |||
'']'' is a ] and ] series, in which a boy is taught to play Go by the spirit of an ancient Go player. At the end of each episode in the original anime, there is a short segment of approximately three minutes where a simple concept of Go is taught. Through the first few episodes, a new player can be taught the concepts of the game in a very simple and easy to understand format. This segment appears to be mainly geared towards children. Hikaru No Go was extremely popular during its original run, and was also highly regarded by critics. A direct result of its success was that Go's popularity (which had been in decline for years in Japan) skyrocketed, especially amongst the young, and its popularity also increased in China and Korea. Today interest in the game remains relatively high, in large part thanks to this series. | |||
=== Capturing tactics === | |||
In the ] and ] series "]", ] is mentioned to be a master at ] and Go. Although seemingly unmotivated and lazy, his intellect is proved when playing his sensei in these games. He never loses. In fact, a habit Shikimaru developed when playing ] and Go is even carried into his battles. | |||
There are several tactical constructs aimed at capturing stones.{{sfn|Kim|Jeong|1997|pp=80–98}} These are among the first things a player learns after understanding the rules. Recognizing the possibility that stones can be captured using these techniques is an important step forward. | |||
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| l| | | | 10| | | | | |||
| l| | | | | | | | | |||
| l| | | | | | | | |22}} | |||
<div class="thumbcaption" style="font-size: 88%;"> | |||
One popular Chinese/Japanese movie is aka ''The Go Masters''. The movie depicts the time period when the Japanese army invaded China. The story begins when a Japanese Army Captain forces a famous Chinese Go player to play at a Go match. Due to resentment of the invasion, the Chinese player cuts off the finger that is used to hold Go stones. The story ends at a post-war time, where both the Japanese Captain and the Chinese Go player meet and play a peaceful game. | |||
'''A ladder.''' Black cannot escape unless the ladder connects to black stones further down the board that will intercept with the ladder or if one of white's pieces has only one liberty. | |||
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The most basic technique is the ''ladder''.{{sfn|Kim|Jeong|1997|pp=88–90}} This is also sometimes called a "running attack", since it unfolds as one player trying to outrun the other's attack. To capture stones in a ladder, a player uses a constant series of capture threats (atari), giving the opponent only one place to place his stone to keep his group alive. This forces the opponent to move into a zigzag pattern (surrounding the ladder on the outside) as shown in the adjacent diagram to keep the attack coming. Unless the pattern runs into friendly stones along the way, the stones in the ladder cannot avoid capture. However, if the ladder can run into other black stones, thus saving them, then experienced players recognize the futility of continuing the attack. These stones can also be saved if a suitably strong threat can be forced elsewhere on the board, so that two Black stones can be placed here to save the group. | |||
Go was depicted in the films '']'', '']'', '']'', '']'' and '']'' among many others. See the for an extensive list. | |||
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{{Goban 9x9 | |||
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Go is depicted in the movie ]. | |||
'''A net.''' The chain of three marked Black stones cannot escape in any direction, since each Black stone attempting to extend the chain outward (on the red circles) can be easily blocked by one White stone. | |||
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Another technique to capture stones is the so-called ''net'',{{sfn|Kim|Jeong|1997|pp=91–92}} also known by its Japanese name, ''geta''. This refers to a move that loosely surrounds some stones, preventing their escape in all directions. An example is given in the adjacent diagram. It is often better to capture stones in a net than in a ladder, because a net does not depend on the condition that there are no opposing stones in the way, nor does it allow the opponent to play a strategic ladder breaker. However, the ladder only requires one turn to kill all the opponent's stones, whereas a net requires more turns to do the same. | |||
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==The Go world== | |||
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===Ranks=== | |||
{{Goban 9x9 | |||
] in ], ].]] | |||
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{{main|Go ranks and ratings}} | |||
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| l| | | w| b| | | | | |||
| l| | | | b| | | | |22}} | |||
<div class="thumbcaption" style="font-size: 88%;"> | |||
In countries where Go is popular, ranks are employed to indicate playing strength. | |||
'''A snapback.''' Although Black can capture the white stone by playing at the circled point, the resulting shape for Black has only one liberty (at 1), thus White can then capture the three black stones by playing at '''1''' again (''snapback''). | |||
From about the ], the Japanese formalised the teaching and ranking of Go. The system is comparable to that of ] schools; and is considered to be derived ultimately from court ranks in China. | |||
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A third technique to capture stones is the ''snapback''.{{sfn|Kim|Jeong|1997|pp=93–94}} In a snapback, one player allows a single stone to be captured, then immediately plays on the point formerly occupied by that stone; by so doing, the player captures a larger group of their opponent's stones, in effect ''snapping back'' at those stones. An example can be seen on the right. As with the ladder, an experienced player does not play out such a sequence, recognizing the futility of capturing only to be captured back immediately. | |||
=== Reading ahead === | |||
Beginning players today start at a rank of between 25 and 30 ''kyu'' 級. The ''kyu'' ranking then decreases in magnitude as the player becomes stronger, dropping down to 1 ''kyu'' or 1k. Since beginners will commonly progress through elementary concepts quickly, it may be difficult to set a solid kyu ranking for new players. Players who have progressed through the ''kyu'' ranks and passed the 1 ''kyu'' mark are then ranked at 1 ''dan'' 段 or 1d, sometimes called ''shodan'' 初段. The player then could advance through the amateur ''dan'' ranks up to amateur 7 ''dan'', which only few players achieve. That playing level is roughly equivalent to where the ranks for professionals start with pro 1 ''dan'' going up to 9 ''dan'' (also sometimes called ''ping'' or ''p'' as in 9p to avoid confusion between a 1 dan professional and a weaker amateur 6 dan). The distinction between each amateur rank is, by definition, one handicap stone. Professional ranks are awarded by professional organizations and though they are less well defined, they are closer, so that an average 1p might need three handicap stones against a prime 9p (although they would play even games if they were to meet in a tournament). | |||
One of the most important skills required for strong tactical play is the ability to read ahead.{{sfn|Davies|1995|p=5}} Reading ahead includes considering available moves to play, the possible responses to each move, and the subsequent possibilities after each of those responses. Some of the strongest players of the game can read up to 40 moves ahead even in complicated positions.<ref name=TreasureChest>{{citation | chapter = Memories of Kitani | title = The Treasure Chest Enigma | last = Nakayama | first = Noriyuki | publisher = Slate & Shell | year = 1984 | isbn = 978-1-932001-27-3 | pages =16–19}}</ref> | |||
As explained in the scoring rules, some stone formations can never be captured and are said to be alive, while other stones may be in a position where they cannot avoid being captured and are said to be dead. Much of the practice material available to players of the game comes in the form of life and death problems, also known as ].<ref name=Tsumego>{{Citation | url = http://www.yomiuri.co.jp/dy/columns/0001/305.htm | last = van Zeijst | first = Rob | publisher = ] | title = Whenever a player asks a top professional ... | access-date = 2008-06-09 | archive-date = 2008-05-11 | archive-url = https://web.archive.org/web/20080511122600/http://www.yomiuri.co.jp/dy/columns/0001/305.htm | url-status = dead}}</ref> In such problems, players are challenged to find the vital move sequence that kills a group of the opponent or saves a group of their own. Tsumego are considered an excellent way to train a player's ability at reading ahead,<ref name=Tsumego /> and are available for all skill levels, some posing a challenge even to top players. | |||
Among amateur players, handicaps are determined by the difference in ranks. If a 3k and a 7k player were to play each other, the 7k player would place four handicap stones at the start of the game. Handicaps up to nine stones are common in club play, and correspond well to rank differences. In a small club, ranks may be decided informally and adjusted when players consistently win or lose. In a larger club, a mathematical ranking system gives better results. Players can then be promoted or demoted based on their strength as calculated from their wins and losses. | |||
=== |
=== Ko fighting === | ||
] | |||
Like many other games, a game of Go may be timed. There are four typical methods of timing a game: | |||
* ''Absolute'': a specific amount of time is given for the entire game, regardless of how fast or slow each player is. This is extremely rare. | |||
* ''Byo-Yomi'' (''Japanese Timing''): After the main time is depleted, a player has a certain number of time periods (typically around 30 seconds). After each move, the number of time periods that the player took (possibly zero) is subtracted. For example, if a player has three 30-second time periods and takes 30 or more (but less than 60) seconds to make a move, he loses one time period. With 60-89 seconds, he loses two time periods, and so on. If, however, he takes less than 30 seconds, the timer simply resets without subtracting any periods. This is written as <maintime> + <byo-yomi time period>x<number of byo-yomi time periods>. | |||
* ''Canadian Byo-Yomi'': After the main time is depleted a player must make a certain number of moves within a certain period of time. For example, 5 moves within 2 minutes. If 5 moves are made in time, the timer resets to 2 minutes again. This is written as <main time>/<byo-yomi time period>/<number of moves to be completed in each byo-yomi time period>. () | |||
* ''Progressive Byo-Yomi'': usually this is based on Canadian Byo-Yomi, where after main time is depleted the first number of moves must be played in a time, but the next number of moves may be different and played in a different amount of time. For instance, in one amateur tournament the main time of 50 minutes was followed by twenty moves in five minutes, then forty moves in five minutes, then sixty moves in five minutes (the last time period being repeated until the game ended). Thus, this tournament's timing was written 50+20/5+40/5+60/5 (it is common to leave minutes as numbers without units while seconds are usually written in the form 5s). | |||
In situations when the ] applies, a ko fight may occur.{{sfn|Kim|Jeong|1997|pp=144–147}} If the player who is prohibited from capture is of the opinion that the capture is important because it prevents a large group of stones from being captured for instance, the player may play a ''ko threat''.{{sfn|Kim|Jeong|1997|pp=144–147}} This is a move elsewhere on the board that threatens to make a large profit if the opponent does not respond. If the opponent does respond to the ko threat, the situation on the board has changed, and the prohibition on capturing the ko no longer applies. Thus the player who made the ko threat may now recapture the ko. Their opponent is then in the same situation and can either play a ko threat as well or concede the ko by simply playing elsewhere. If a player concedes the ko, either because they do not think it important or because there are no moves left that could function as a ko threat, they have ''lost'' the ko, and their opponent may connect the ko. | |||
Japanese Timing is equivalent to Canadian Byo-Yomi when the "certain number of moves" is equal to one. | |||
Instead of responding to a ko threat, a player may also choose to ''ignore'' the threat and connect the ko.{{sfn|Kim|Jeong|1997|pp=144–147}} They thereby win the ko, but at a cost. The choice of when to respond to a threat and when to ignore it is a subtle one, which requires a player to consider many factors, including how much is gained by connecting, how much is lost by not responding, how many possible ko threats both players have remaining, what the optimal order of playing them is, and what the ''size''—points lost or gained—of each of the remaining threats is.<ref name="Tavernier">{{cite journal | |||
===Top players=== | |||
| url = https://www.britgo.org/files/bgj/bgj110.pdf | |||
{{main|Go players}} | |||
| title = Analyzing Ko Struggles Theoretically | |||
Although the game was invented and developed in ], Japanese players dominated the international Go scene for most of the twentieth century. However, top players from ] (since the 1980s) and ] (since the 1990s) have reached an even higher level. | |||
| first = Karel | |||
Nowadays, top players from these three countries are of comparable strength, although top Korean players seem to have an edge, dominating the major international titles, winning 23 tournaments in a row between 2000 and 2002. | |||
| last = Tavernier | |||
All three countries have a number of professional Go tournaments. The top Japanese tournaments have a prize purse comparable to that of professional golf tournaments in the United States though tournaments in ] and ] are less lavishly funded. | |||
| date = Spring 1998 | |||
| access-date = 8 October 2013 | |||
| journal = British Go Journal | |||
| issue = 110 | |||
| page = 11 | |||
| archive-url = https://web.archive.org/web/20150131052153/https://www.britgo.org/files/bgj/bgj110.pdf | |||
| archive-date = 31 January 2015 | |||
| url-status = live | |||
}}</ref> | |||
Frequently, the winner of the ko fight does not connect the ko but instead captures one of the chains that constituted their opponent's side of the ko.{{sfn|Kim|Jeong|1997|pp=144–147}} In some cases, this leads to another ko fight at a neighboring location. | |||
Players from other countries have traditionally been much weaker, except for some players who have taken up professional courses in one of the Asian countries. | |||
This is attributed to the fact that details of the game have been unknown outside of Asia for most of the game's history. | |||
A German scientist, ], is credited with the first systematic description of the game in a Western language in AD ]; it was not until the 1950s that Western players would take up the game as more than a passing interest. In 1978, Manfred Wimmer became the first Westerner to receive a professional player's certificate from an Asian professional Go association. It was not until 2000 that a Westerner, ], achieved the top rank awarded by an Asian Go association. | |||
== |
== History == | ||
{{Main|History of Go}} | |||
* ] | |||
* ] | |||
* ] | |||
* ] | |||
* ] | |||
* ] | |||
* ] | |||
* ] | |||
* ] | |||
* ] | |||
* ] | |||
* ] | |||
* ] | |||
* ] | |||
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=== Origin in China === | |||
{{wikiquote}} | |||
The earliest written reference to the game is generally recognized as the historical annal '']''<ref name="The Tso Chuan book" />{{sfn|Fairbairn|1995|p={{page needed|date=May 2014}}}} ({{circa|4th century}} BCE),<ref name="chronology2" /> referring to a historical event of 548 BCE. It is also mentioned in Book XVII of the '']''<ref name=chronology2 /> and in two books written by ]{{sfn|Fairbairn|1995|p={{page needed|date=May 2014}}}}<ref>{{cite magazine|last=Potter|first=Donald L.|year=1984|title=Go in the Classics|magazine=]|issue=37|publisher=Ishi Press|location=Tokyo|pages=16–18}}<br/>– {{cite magazine|last=Potter|first=Donald L.|year=1985|title=Go in the Classics (ii): the Tso-chuan|magazine=]|issue=42|publisher=Ishi Press|location=Tokyo|pages=19–21}}<br/>Via {{cite web|title=Go in the Classics|publisher=Kiseido Publishing Company|url=http://www.kiseido.com/classics.htm|access-date=2007-11-02|archive-date=2010-12-18|archive-url=https://web.archive.org/web/20101218113923/http://kiseido.com/classics.htm|url-status=dead}}</ref> ({{circa|3rd century}} BCE).<ref name=chronology2 /> In all of these works, the game is referred to as {{transliteration|zh|ISO|''yì''}} ({{lang|zh-Hant|弈}}). Today, in China, it is known as '''''weiqi''''' ({{zh|t=圍棋|s=围棋|p={{audio|Zh-wéiqí.ogg|wéiqí|help=no}}|w=wei ch'i}}), {{lit|encirclement board game}}. | |||
Go was originally played on a 17×17 line grid, but a 19×19 grid became standard by the time of the ] (618–907 CE).{{sfn|Fairbairn|1995|p={{page needed|date=May 2014}}}} Legends trace the origin of the game to the mythical ] ] (2337–2258 BCE), who was said to have had his counselor ] design it for his unruly son, ], to favorably influence him.<ref>{{cite book |last1=Yang |first1=Lihui |last2=An |first2=Deming |title=Handbook of Chinese Mythology |date=2008 |publisher=Oxford University Press |isbn=978-0-19-533263-6 |page=228 |url=https://books.google.com/books?id=gGD5go6iCUYC&dq=eldest+son%2C+danzhu&pg=PA228 |language=en}}</ref><ref>{{Citation |last1=Yang |first1=Lihui |title=Handbook of Chinese mythology |year=2005 |publisher=ABC-CLIO Ltd |isbn=978-1-57607-806-8 |url=https://books.google.com/books?id=Wf40ofEMGzIC&q=Yao+is+said+to+have+invented+the+game+of+Weiqi&pg=PA228 |first2=Deming|last2=An|first3=Jessica Anderson |last3=Turner |page=228}}</ref> Other theories suggest that the game was derived from Chinese tribal warlords and generals, who used pieces of stone to map out attacking positions.{{sfn|Masayoshi|2005|p={{page needed|date=May 2014}}}}{{sfn|Lasker|1960|p={{page needed|date=May 2014}}}} | |||
==Books== | |||
*''Life, Liberty & the Pursuit of Territory'', Richard Zhang, Ryan Wang, Compupress, 2006. http://www.lifelibertyterritory.com | |||
*''Go for Beginners'', Iwamoto Kaoru, Ishi Press, Tokyo, 1972. ISBN 0870401661 | |||
*''An Introduction to Go'', James Davies, Richard Bozulich, Ishi Press, Tokyo, 1984. | |||
*''Lessons in the Fundamentals of Go'', Kageyama Toshiro, Kiseido Publishing Company, 1978. (A more advanced book, suitable for people with a certain amount of experience.) | |||
*''Basic Techniques of Go'', Haruyama Isamu, Nagahara Yoshiaki, Ishi Press, Tokyo, 1969. (Again, a more advanced book.) | |||
*''Go: the World's Most Fascinating Game'', Vol 1 - Introduction, Vol 2 - Basic Techniques, Nihon Kiin, 1973. | |||
*''The Protracted Game: A Wei-Chi Interpretation of Maoist Revolutionary Strategy'', Scott A. Boorman, Oxford University Press, 1969. | |||
*, Troy Anderson, Free Press, 2004. ISBN 0743258142 | |||
In China, Go had an important status among elites and was associated with ideas of self-cultivation, wisdom, and gentlemanly ideals.<ref name="Berge-Becker">{{Cite book |last=Berge-Becker |first=Zach |title=Games & Play in Chinese & Sinophone Cultures |date=2024 |publisher=] |isbn=9780295752402 |editor-last=Guo |editor-first=Li |location=Seattle, WA |pages= |chapter=Groups on the Grid: Weiqi Cultures in Song-Yuan-Ming China |editor-last2=Eyman |editor-first2=Douglas |editor-last3=Sun |editor-first3=Hongmei}}</ref>{{Rp|page=23}} It was considered one of the ] of the ], along with ], ] and playing the musical instrument ].<ref>{{Cite web|last=Pinckard|first=William|title=The Four Accomplishments|year=1989|url= http://www.kiseido.com/printss/four.html|access-date=2007-11-02|archive-url= https://web.archive.org/web/20080625104739/http://www.kiseido.com/printss/four.html|archive-date=2008-06-25|url-status=dead}} In {{Cite book|last=Pinckard|first=William|editor-last=Akiko|editor-first=Kitagawa|date=2010|title=Japanese Prints and the World of Go|publisher=Kiseido Publishing Company|isbn=978-4-90657430-8|url= http://www.kiseido.com/printss/ukiyoedx.html|url-status=dead|archive-url= https://web.archive.org/web/20080316051106/http://www.kiseido.com/printss/ukiyoedx.html|archive-date=2008-03-16}}</ref> In ancient times the rules of Go were passed on verbally, rather than being written down.{{sfn|Chen|2011|p=1}} | |||
==External links== | |||
{{book|Go}} | |||
{{commons|Go}} | |||
=== Learning Go === | |||
* A guide for the beginning player written in English, not translated from other languages | |||
* | |||
* is an excellent resource to learn the basics; includes Java applets. | |||
* | |||
* | |||
* | |||
* | |||
* is owned by Janice Kim 3p and has a very good beginner introduction. | |||
* where to look when you understand the rules and wonder what to do next. | |||
* has over 3000 problems for practice in a Java applet. | |||
* has a collection of 750 problems used in Korea to help develop players of amateur dan strength. | |||
* explains the rules of Go and, through step-by-step illustrations, shows how to play the game. The book also covers the origins of the game and its history and culture. | |||
<gallery widths="240" heights="200"> | |||
=== Resources === | |||
File:Sui Dynasty Go Board.jpg|Model of a 19×19 Go board, from a tomb of the ] (581–618 CE) | |||
* is a wiki devoted entirely to the game of Go - it even has special markup for displaying Go diagrams. | |||
File:Anonymous-Astana Graves Wei Qi Player.jpg|Painting of a woman playing Go, from the ]. Tang dynasty, {{circa|744 CE}}. | |||
* The Usenet newsgroup has its own FAQ document, the . | |||
File:Zhou Wenju 重屏会棋图 Palace Museum, Detail of Go Players.jpg|] playing Go with his brothers. Detail from a painting by ] (fl. 942–961 CE), ] dynasty. | |||
* Offers reviews of Go books old and new alike. | |||
</gallery> | |||
* has a particular emphasis on the coverage of the world Go scene, with regularly updated news about all major professional and amateur tournaments. You can register and access a huge database of Go games directly on the site. It also hosts articles, studying material, and much more. | |||
* including classifications of boards by grain and classic composition. | |||
* A large collection of information and resources about Go, organised by category. | |||
* gives a flavour of what a Go tournament is like. (Uses ]) | |||
=== Spread to Korea and Japan === | |||
===Internet Go=== | |||
Go was introduced to Korea sometime between the 5th and 7th centuries CE, and was popular among the higher classes. In Korea, the game is called '''''baduk''''' ({{Korean|hangul=바둑}}), and a variant of the game called ] was developed by the 16th century. Sunjang baduk became the main variant played in Korea until the end of the 19th century, when the current version was reintroduced from Japan.<ref>{{Citation | url = http://english.baduk.or.kr/sub01_01.htm?menu=f11 | publisher = Korean Baduk Association | title = History of Korean baduk | access-date = 2008-11-13}}</ref>{{sfn|Fairbairn|2000|p={{page needed|date=May 2014}}}} | |||
Go can be played on the Internet against opponents from around the world on numerous : | |||
* The , web-based server, Go and many other games, localized to 15 languages. | |||
* The , Korean server with an English Windows client. | |||
* The , a turn-based server run on ] software. | |||
* The is such a server, complete with its own easy-to-use ] client, teaching facilities and introductory material. | |||
* The , with a Java-based browser client. | |||
* The , located in Taiwan, with its own English client. | |||
* The , another turn-based server, this one centred around tournament play. | |||
* The , located in Korea, with its own client. | |||
* The , the "original" server. Several official and 3rd party clients are available. | |||
* The , quite a new browser based Go server, includes many options and a ranking system of its own. Players from various countries. | |||
* The , located in China, with its own client. | |||
* The , located in China, with its own client. | |||
* The , located in Korea, with its own client. | |||
* The , with a Java-based browser client. | |||
* The , another turnbased site with also other games. | |||
* The , A new, browser-based, turn-based server with mini-tournaments, conditional moves and many other options. | |||
* The , browser-based, multinational go server. | |||
* The , browser-based, multinational chess & go server. | |||
The game reached Japan in the 7th century CE—where it is called {{nihongo|'''''go'''''|碁|}} or {{nihongo|'''''igo'''''|囲碁|}}. It became popular at the ] in the 8th century,<ref name=HistJapan2>{{Citation|url=http://www.nihonkiin.or.jp/lesson/knowledge-e/history02.htm |publisher=] |title=History of Go in Japan: part 2 |access-date=2007-11-02 |url-status=dead |archive-url=https://web.archive.org/web/20071114231818/http://www.nihonkiin.or.jp/lesson/knowledge-e/history02.htm |archive-date=2007-11-14}}</ref> and among the general public by the 13th century.<ref name=HistJapan3>{{Citation|url=http://www.nihonkiin.or.jp/lesson/knowledge-e/history03.htm |publisher=] |title=History of Go in Japan: part 3 |access-date=2007-11-02 |url-status=dead |archive-url=https://web.archive.org/web/20071114231823/http://www.nihonkiin.or.jp/lesson/knowledge-e/history03.htm |archive-date=2007-11-14}}</ref> The game was further formalized in the 15th century. In 1603, ] re-established Japan's unified national government. In the same year, he assigned the then-best player in Japan, a ] monk named Nikkai (né Kanō Yosaburo, 1559), to the post of ] (Minister of Go).<ref name=timeline>{{harvnb|Fairbairn|Hall|2007|loc=''History and Timelines'' "Timeline 1600–1867"}}{{page needed|date=June 2020}}</ref> | |||
===Recorded games=== | |||
* The popular ] is used to exchange Go lessons and recorded games. | |||
* - Online professional Go games database (more than 35000 games). Contains game records, game lists, fuseki and joseki trees. More than 3000 games for free. | |||
* - Approximately 10,000 professional games can be reviewed for free and without registration. | |||
* Several free reading and authoring programs are listed at | |||
* also hosts a database of more than 30000 professional Go games in SGF format (free registration required, which takes 1-2 days to process) | |||
* provides more than 2000 professional games, including almost all known games of Cho Chikun | |||
* A smaller collection of professional games in SGF format is available without registration at . | |||
* Amateur games are reviewed at . | |||
Nikkai took the name ] and founded the ] Go school.<ref name=timeline /> Several ] were founded soon after.<ref name=timeline /> These officially recognized and subsidized Go schools greatly developed the level of play and introduced the ] of ranking players.<ref name=ranks>{{harvnb|Fairbairn|Hall|2007|loc=''Articles on Famous Players'' "Honinbo Dosaku"}}{{page needed|date=May 2014}}</ref> Players from the four schools (Hon'inbō, Yasui, Inoue and Hayashi) competed in the annual ]s, played in the presence of the ].<ref name=castlegames>{{harvnb|Fairbairn|Hall|2007|loc=''History and Timelines'' "Castle Games 1626–1863"}}{{page needed|date=May 2014}}</ref> | |||
===Go software=== | |||
====Go engines==== | |||
* , free and strong Go-playing program, ~10-12 Kyu | |||
* ], free (in ]) Go-playing engine, 8-9 Kyu | |||
* is a free 9x9 version of David Fotland's | |||
* , free (but a password will be required) Java applet for solving life-and-death problems (]), of professional level. ''(Those problems, set in limited spaces, with a clear objective, are essentially the only subdomain of go where real progress have been made in ].) | |||
* is an open-source Go playing program written in Java. | |||
<gallery widths="240" heights="200"> | |||
====Go clients==== | |||
GO Tale Genji Takekawa.JPG|Detail from a Japanese illustrated ] of '']''. ], 12th century CE. | |||
* , SGF editor and client for GNU Go (you can play standalone) in ]. | |||
Korean Game from the Carpenter Collection, ca. 1910-1920.jpg|A Korean couple playing Go in traditional dress. Photographed between 1910 and 1920. | |||
* , SGF editor and client for IGS, in ]; and native variants, and (has a 3D display) | |||
</gallery> | |||
* , Go client (Linux, etc) | |||
* , Go client for KGS in Java. Also functions as an SGF editor. | |||
* , standalone (against GNU Go) and Internet Go client for Mac OS X | |||
* , J2ME Go client that runs on java-enabled cellphones and PDAs. | |||
* , Windows Mobile Go client for Smartphone and Pocket PC. | |||
* , Client for Windows. Written in Visual Basic. Open source. Also contains an SGF viewer, GNU Go player and NNGS Server. | |||
* , GO.FEUP 3D GO Game (free Windows 3D Opengl Game with HumanVsCPU and CPUvsCPU features, now in French too). | |||
=== |
=== Internationalization === | ||
Despite its widespread popularity in East Asia, Go has been slow to spread to the rest of the world. Although there are some mentions of the game in western literature from the 16th century forward, Go did not start to become popular in the West until the end of the 19th century, when German scientist ] wrote a treatise on the game.<ref name=GoHistEU>{{cite book|last= Pinckard|first=William|chapter=History and Philosophy of Go|year=1992|pages=23–25|editor-last=Bozulich|editor-first=Richard|title=The Go Player's Almanac|publication-date=2001|edition=2nd|publisher=Kiseido Publishing Company|isbn=978-4-906574-40-7}}</ref> By the early 20th century, Go had spread throughout the ] and ] empires. In 1905, ] learned the game while in Berlin. When he moved to New York, Lasker founded the New York Go Club together with (amongst others) Arthur Smith, who had learned of the game in Japan while touring the East and had published the book ''The Game of Go'' in 1908.<ref name=agahbk95>{{Citation | url = http://www.usgo.org/archive/agahbk95.html | title = AGA 1995 Historical Book | publisher = American Go Association | access-date = 2008-06-11 | url-status = dead | archive-url = https://web.archive.org/web/20110806204728/http://www.usgo.org/archive/agahbk95.html | archive-date = 2011-08-06}}</ref> Lasker's book ''Go and Go-moku'' (1934) helped spread the game throughout the U.S.,<ref name=agahbk95 /> and in 1935, the ] was formed. Two years later, in 1937, the German Go Association was founded. | |||
* , a Java program for practising Go problems. | |||
* , a ] ] which includes GNU Go, Go clients, games and documentation. | |||
* , SGF viewer/editor for Windows. | |||
* , Multiplatform program to study ], life and death problems. | |||
* , web-based program for visualizing such concepts as Influence, Concentration, Tension and Instability. | |||
* Fuseki, Joseki, Tesuji, "Good Shape"- Pattern Expert, SGF Editor, SQL database and GNU Go Client. | |||
* Windows program to play, study, and print Go games. English, Japanese, Korean, and Russian. | |||
World War II put a stop to most Go activity, since it was a popular game in Japan, but after the war, Go continued to spread.<ref>{{Citation|url=http://www.yomiuri.co.jp/igo_e/040.htm |title=The Magic of Go – 40. Go in Europe |publisher=] |last=Bozulich |first=Richard |access-date=2008-06-16 |archive-url=http://webarchive.loc.gov/all/20011109202817/http://www.yomiuri.co.jp/igo_e/040.htm |archive-date=November 9, 2001 |url-status=dead}}</ref> For most of the 20th century, the ] played a leading role in spreading Go outside East Asia by publishing the English-language magazine '']'' in the 1960s, establishing ] in the U.S., Europe and South America, and often sending professional teachers on tour to Western nations.<ref name=ProVisits>{{Citation | url = https://www.britgo.org/history/pros.html | title = Pro Go Player visits to UK & Ireland (since 1964) | author = British Go Association | access-date= 2007-11-17}}</ref> Internationally, the game had been commonly known since the start of the twentieth century by its shortened Japanese name, and ] are derived from their Japanese pronunciation. | |||
====Utilities==== | |||
* is a free database and pattern search engine for sgf game records. | |||
* is a database of professional and amateur Go games. It allows searching by fuseki, joseki, positions and game information fields. | |||
* supports SGF for inserting Go diagrams directly into Wiki articles. | |||
* A Go game recorder and SGF viewer/editor for PalmOS. | |||
* A Go game recorder and SGF viewer/editor for PocketPC, also including the Vieka GNU Go port for PocketPC allowing you to play against your PocketPC PDA. | |||
* - Perl module useful for creating web pages with tournament tables directly from sets of SGF files, also available through CPAN. | |||
* , J2ME Go game recorder that runs on java-enabled mobiles and PDAs. Development status is alpha but already useful. | |||
* , J2ME sgf player, recorder that runs on java-enabled mobiles. | |||
In 1996, ] astronaut ] and Japanese astronaut ] became the first people to play Go in space. They used a special Go set, which was named Go Space, designed by Wai-Cheung Willson Chow. Both astronauts were awarded honorary ]s by the ].{{sfn|Peng|Hall|1996}} | |||
===Disambiguation=== | |||
*Go is also the name of (Licensed to Gibson in the US). | |||
*], the late wealthy ] of Go (particularly in the U.S.) proposed spelling the word in English as "'''goe'''" to differentiate it from the verb "to go", but this spelling is not widely used —even in events which are sponsored by the Ing foundation. | |||
{{As of|2015|December}}, the ] has 75 member countries, with 67 member countries outside East Asia.<ref name="igf-members">{{Citation|author=International Go Federation|title=IGF members|date=22 June 2010 |url=http://www.intergofed.org/members/igf-member-countries.html|access-date=December 14, 2015}}</ref> Chinese cultural centres across the world are promoting Go, and cooperating with local Go associations, for example the seminars held by the Chinese cultural centre in Tel Aviv, Israel, together with the Israeli Go association.<ref name="Ambassador Go 围棋 Cup 2018">{{Citation|author=China Cultural Centre in Tel Aviv|title=Go in Tel Aviv|url=https://ccctlv.org/en/events/ambassador-go-%E5%9B%B4%E6%A3%8B-cup-2018/|access-date=April 12, 2019}}</ref> | |||
{{featured article}} | |||
== Competitive play == | |||
] | |||
] | |||
] | |||
] | |||
=== Ranks and ratings === | |||
{{Link FA|de}} | |||
{{Main|Go ranks and ratings}} | |||
{{Link FA|fr}} | |||
] problem in the corner of the board, at the ] in ], Texas, 2003.]] | |||
{{Link FA|hu}} | |||
{{Link FA|ru}} | |||
In Go, rank indicates a player's skill in the game. Traditionally, ranks are measured using ''kyu'' and ''dan'' grades,{{sfn|Nihon Kiin|1973|p=188}} a system also adopted by many ]. More recently, mathematical rating systems similar to the ] have been introduced.<ref name=EGFRating>{{Citation | url = http://europeangodatabase.eu/EGD/EGF_rating_system.php#System | title = EGF Official Ratings | first=Ales | last = Cieply | publisher = European Go Federation (EGF)| access-date=2009-11-06}}</ref> Such rating systems often provide a mechanism for converting a rating to a kyu or dan grade.<ref name=EGFRating /> Kyu grades (abbreviated ''k'') are considered student grades and decrease as playing level increases, meaning 1st kyu is the strongest available kyu grade. Dan grades (abbreviated ''d'') are considered master grades, and increase from 1st dan to 7th dan. ] equals a ] in eastern martial arts using this system. The difference among each amateur rank is one handicap stone. For example, if a 5k plays a game with a 1k, the 5k would need a handicap of four stones to even the odds. Top-level amateur players sometimes defeat professionals in tournament play.<ref name=EGFDatabase>{{Citation | url = http://www.europeangodatabase.eu/EGD/Player_Card.php?&key=12633346 | |||
{{Link FA|vi}} | |||
| title = EGF Tournament Database | publisher = Association for Go in Italy (AGI) | access-date=2008-06-19}}</ref> Professional players have ] (abbreviated ''p''). These ranks are separate from amateur ranks. | |||
The rank system comprises, from the lowest to highest ranks: | |||
] | |||
{| class="wikitable" | |||
] | |||
|- | |||
] | |||
!|Rank Type | |||
] | |||
!|Range | |||
] | |||
!|Stage | |||
] | |||
|- | |||
] | |||
|Double-digit ''kyu'' | |||
] | |||
|30–21k | |||
] | |||
|Beginner | |||
] | |||
|- | |||
] | |||
|Double-digit ''kyu'' | |||
] | |||
|20–10k | |||
] | |||
|Casual player | |||
] | |||
|- | |||
] | |||
|Single-digit ''kyu'' | |||
] | |||
|9–1k | |||
] | |||
|Intermediate/club player | |||
] | |||
|- | |||
] | |||
|Amateur ''dan'' | |||
] | |||
|1–7d (where 8d is a special title) | |||
] | |||
|Advanced player | |||
] | |||
|- | |||
] | |||
|Professional ''dan'' | |||
] | |||
|1–9p (where 10p is a special title) | |||
] | |||
|Professionals | |||
] | |||
|} | |||
] | |||
] | |||
=== Tournament and match rules === | |||
] | |||
{{See also|Go competitions}} | |||
] | |||
Tournament and match rules deal with factors that may influence the game but are not part of the actual rules of play. Such rules may differ between events. Rules that influence the game include: the setting of compensation points (]), handicap, and time control parameters. Rules that do not generally influence the game are the tournament system, pairing strategies, and placement criteria. | |||
] | |||
] | |||
Common tournament systems used in Go include the ],<ref>{{Citation|url=https://www.britgo.org/organisers/mcmahon.html |publisher=British Go Association |title=The McMahon system in a nutshell |access-date=2008-06-11 |archive-url=https://web.archive.org/web/20080518202147/http://www.britgo.org/organisers/mcmahon.html |archive-date=2008-05-18 |url-status=dead}}</ref> ], ]s and the ]. Tournaments may combine multiple systems; many ] use a combination of the league and knockout systems.<ref>{{harvnb|Fairbairn|Hall|2007|loc=''A quick guide to pro tournaments''}}{{page needed|date=May 2014}}</ref> | |||
] | |||
] | |||
Tournament rules may also set the following: | |||
] | |||
* compensation points, called komi, which compensate the second player for the first move advantage of their opponent; tournaments commonly use a compensation in the range of 5–8 points,<ref name=histKomi>{{harvnb|Fairbairn|Hall|2007|loc=''History and Timelines'' "History of Komi"}}{{page needed|date=May 2014}}</ref> generally including a half-point to prevent draws; | |||
] | |||
* handicap stones placed on the board before alternate play, allowing players of different strengths to play competitively (see ] for more information); and | |||
] | |||
* ''superko'': Although the basic ko rule described above covers more than 95% of all cycles occurring in games,<ref name="KoRules">{{Citation | title = Ko Rules | url = http://home.snafu.de/jasiek/korules.html | first = Robert | last = Jasiek | year = 2001 | access-date = 2007-11-30}}</ref> there are some complex situations—], ''eternal life'',{{efn|1=A full explanation of the eternal life position can be found on , it also appears in the official text for Japanese Rules, see .}} etc.—that are not covered by it but would allow the game to cycle indefinitely. To prevent this, the ko rule is sometimes extended to forbid the repetition of ''any'' previous position. This extension is called superko.<ref name="KoRules" /> | |||
=== Time control === | |||
{{See also|Time control|Byoyomi}} | |||
A game of Go may be timed using a ]. Formal time controls were introduced into the professional game during the 1920s and were controversial.{{sfn|Bozulich|2001|pp=92–93}} Adjournments and ]s began to be regulated in the 1930s. Go tournaments use a number of different time control systems. All common systems envisage a single main period of time for each player for the game, but they vary on the protocols for continuation (in ''overtime'') after a player has finished that time allowance.{{efn|1=Roughly, one has the time to play the game and then a little time to finish it off. Time-wasting tactics are possible in Go, so that ''sudden death'' systems, in which time runs out at a predetermined point however many plays are in the game, are relatively unpopular (in the West).}} The most widely used time control system is the so-called ]{{efn|1=Literally in Japanese ''byōyomi'' means 'reading of seconds'.}} system. The top professional Go matches have timekeepers so that the players do not have to press their own clocks. | |||
Two widely used variants of the byoyomi system are:<ref name="Byoyomi">{{Citation | publisher = European Go Federation | url = http://www.eurogofed.org/egf/tourrules.htm | title = EGF General Tournament Rules | access-date = 2008-06-11}}</ref> | |||
* ''Standard byoyomi'': After the main time is depleted, a player has a certain number of time periods (typically around thirty seconds). After each move, the number of full-time periods that the player took (often zero) is subtracted. For example, if a player has three thirty-second time periods and takes thirty or more (but less than sixty) seconds to make a move, they lose one time period. With 60–89 seconds, they lose two time periods, and so on. If, however, they take less than thirty seconds, the timer simply resets without subtracting any periods. Using up the last period means that the player has lost on time. | |||
* ''Canadian byoyomi'': After using all of their main time, a player must make a certain number of moves within a certain period of time, such as twenty moves within five minutes.<ref name="Byoyomi" />{{efn|1=Typically, players stop the clock, and the player in overtime sets his/her clock for the desired interval, counts out the required number of stones and sets the remaining stones out of reach, so as not to become confused. If twenty moves are made in time, the timer is reset to five minutes again.}} If the time period expires without the required number of stones having been played, then the player has lost on time.{{efn|1=In other words, Canadian byoyomi is essentially a standard chess-style time control, based on ''N'' moves in a time period ''T'', imposed after a main period is used up. It is possible to decrease ''T'', or increase ''N'', as each overtime period expires; but systems with constant ''T'' and ''N'', for example 20 plays in 5 minutes, are widely used.}} | |||
=== Notation and recording games === | |||
{{Main article|Go game record}} | |||
Go games are recorded with a simple coordinate system. This is comparable to ], except that Go stones do not move and thus require only one coordinate per turn. Coordinate systems include purely numerical (4–4 point), hybrid (K3), and purely alphabetical.<ref>{{cite web|author=Stas Bekman|url=http://stason.org/TULARC/games/go/5-3-Recording-Go-games.html |title=Go FAQ |publisher=Stason.org |access-date=2014-03-25}}</ref> The ] uses alphabetical coordinates internally, but most editors represent the board with hybrid coordinates as this reduces confusion. | |||
Alternatively, the game record can also be noted by writing the successive moves on a diagram, where odd numbers mean black stones, even numbers mean white stones (or conversely when playing with a handicap), and a notation like "25=22" in the margin means that the 25th stone was played at the same location as the 22nd one, which had been captured in the meantime. | |||
The Japanese word ] is sometimes used to refer to a game record. | |||
In Unicode, Go stones can be represented with black and white circles from the block ]: | |||
* {{unichar|25CB|white circle|html=}} | |||
* {{unichar|25CF|black circle|html=}} | |||
The block ] includes "Go markers"<ref>{{cite web|title=Go markers|url=https://www.unicode.org/charts/PDF/U2600.pdf#search=Go%20markers|work=The Unicode Standard|archive-url=https://web.archive.org/web/20010603010228/https://www.unicode.org/charts/PDF/U2600.pdf|archive-date=2001-06-03|url-status=live}}</ref> that were likely meant for mathematical research of Go:<ref>{{cite web|last1=Dürst|first1=Martin J.|title=Purpose of and rationale behind Go Markers U+2686 to U+2689|url=https://unicode.org/mail-arch/unicode-ml/y2016-m03/0025.html|website=The Unicode Archives|date=2016-03-10}}</ref><ref>{{cite web|author1=Beeton, Barbara|author2=Avtalion, Ori|title=Purpose of and rationale behind Go Markers U+2686 to U+2689|url=https://unicode.org/mail-arch/unicode-ml/y2016-m03/0074.html|website=The Unicode Archives|date=2016-03-15}}</ref> | |||
* {{unichar|2686|white circle with dot right|html=}} | |||
* {{unichar|2687|white circle with two dots|html=}} | |||
* {{unichar|2688|black circle with white dot right|html=}} | |||
* {{unichar|2689|black circle with two white dots|html=}} | |||
=== Top players and professional Go === | |||
{{See also|List of top title holders in Go|Go players|Female Go players|Go professional|List of professional Go tournaments}} | |||
A Go professional is a professional player of the game of Go. There are six areas with professional go associations, these are: China (]), Japan (], ]), South Korea (]), Taiwan (]), the United States (]) and Europe (]). | |||
Although the game was developed in China, the establishment of the ] by ] at the start of the 17th century shifted the focus of the Go world to Japan. State sponsorship, allowing players to dedicate themselves full-time to study of the game, and fierce competition between individual houses resulted in a significant increase in the level of play. During this period, the best player of his generation was given the prestigious title ] (master) and the post of ] (minister of Go). Of special note are the players who were dubbed ] (Go Sage). The only three players to receive this honor were ], ] and ], all of the house ].<ref name=jowa.html/> | |||
] (left), last head of house Hon'inbō, plays against then-up-and-coming ] in the ]. ]] | |||
After the end of the ] and the ] period, the Go houses slowly disappeared, and in 1924, the ] (Japanese Go Association) was formed. Top players from this period often played newspaper-sponsored matches of 2–10 games.<ref>{{Citation | url = http://www.msoworld.com/mindzine/news/orient/go/history/newspaper.html | title = History of Newspaper Go | last = Fairbairn | first = John | access-date = 2018-01-06 | url-status= dead| archive-url= https://web.archive.org/web/20110608021318/http://www.msoworld.com/mindzine/news/orient/go/history/newspaper.html | archive-date= 2011-06-08}}</ref> Of special note are the (Chinese-born) player ] (Chinese: Wu Qingyuan), who scored 80% in these matches and beat down most of his opponents to inferior handicaps,<ref>{{Citation | publisher = GoBase.org | url = http://gobase.org/games/china/misc/disks/matches.html | title = Go Seigen: Match Player | access-date = 2007-06-14}}</ref> and ], who dominated matches in the early 1930s.<ref>{{Citation | last = Fairbairn | first = John | url = http://senseis.xmp.net/?KitaniMinoru | title = Kitani's Streak | access-date = 2007-06-14}}</ref> These two players are also recognized for their groundbreaking work on new ] (]).<ref name=ShinFuseki>{{Citation | url = http://gobase.org/information/players/?pp=Kubomatsu+Katsukiyo | first = John | last = Fairbairn | title = Kubomatsu's central thesis | access-date = 2008-01-17}}</ref> | |||
For much of the 20th century, Go continued to be dominated by players trained in Japan. Notable names included ], ] (born in Taiwan), ], ] and ] (born Cho Ch'i-hun, from South Korea).<ref>{{Citation | publisher = GoBase.org | url = http://gobase.org/games/jp/ | title = List of Japanese titles, prizemoney and winners | access-date = 2008-06-11}}</ref> Top Chinese and Korean talents often moved to Japan, because the level of play there was high and funding was more lavish. One of the first Korean players to do so was ], who studied in the ] 1937–1944. After his return to Korea, the ] (Korea Baduk Association) was formed and caused the level of play in South Korea to rise significantly in the second half of the 20th century.<ref>{{Citation | url = http://www.usgo.org/news/index.php?%23_id=102 | title = KBA Founder Cho Nam Chul passes | first = Janice | last = Kim | publisher = American Go Association | access-date = 2008-06-11}}</ref> In China, the game declined during the ] (1966–1976) but quickly recovered in the last quarter of the 20th century, bringing Chinese players, such as ] and ], on par with their Japanese and South Korean counterparts.<ref>{{Citation | url = http://www.societies.cam.ac.uk/cugos/tesuji/weiqi_chinese_culture.html | title = Weiqi in Chinese Culture | last = Matthews | first = Charles | access-date = 2007-06-04 | archive-date = 2007-11-30 | archive-url = https://web.archive.org/web/20071130002057/http://www.societies.cam.ac.uk/cugos/tesuji/weiqi_chinese_culture.html | url-status = dead }}</ref> The ] (today part of the China Qiyuan) was established in 1962, and professional dan grades started being issued in 1982.<ref>{{cite web|url=http://sports.sina.com.cn/go/2016-07-22/doc-ifxuhukz0789072.shtml|title=中国围棋职业段位制的历史|author=朱宝训|publisher=]|date=22 July 2016|access-date=7 January 2018|language=zh}}</ref> Western professional Go began in 2012 with the American Go Association's Professional System.<ref>{{cite web|url=http://www.usgo.org/aga-professional-system|title=AGA Professional System|publisher=usgo.org|access-date=3 March 2015}}</ref> In 2014, the European Go Federation followed suit and started their professional system.<ref>{{cite web|url=http://www.eurogofed.org/proqualification/|title=1st European Pro Qualification 2014|year=2014|access-date=11 January 2015}}</ref> ] plays against Russian player ], seven-time European Champion and one of the few non-East Asian players to reach ] status.]] | |||
With the advent of major international titles from 1989 onward, it became possible to compare the level of players from different countries more accurately. ] of South Korea won the first edition of the Quadrennial ] in 1989. His disciple ] was the dominant player in international Go competitions for more than a decade spanning much of 1990s and early 2000s; he is also credited with groundbreaking works on the endgame. Cho, Lee and other South Korean players such as ], ] and ] between them won the majority of international titles in this period.<ref>{{Citation | publisher = GoBase.org | url = http://gobase.org/games/nn/ | title = List of International titles, prizemoney and winners | access-date = 2008-06-11}}</ref> Several Chinese players also rose to the top in international Go from 2000s, most notably ], ], ] and ]. {{As of|2016}}, Japan lags behind in the international Go scene. | |||
Historically, more men than women have played Go. Special tournaments for women exist, but until recently, men and women did not compete together at the highest levels; however, the creation of new, open tournaments and the rise of strong female players, most notably ], have in recent years highlighted the strength and competitiveness of emerging female players.{{sfn|Shotwell|2003|p={{page needed|date=June 2020}}}} | |||
The level in other countries has traditionally been much lower, except for some players who had preparatory professional training in East Asia.{{efn|1=] toured Europe around 1970, and reported (''Go Review'') a general standard of amateur 4 ''dan''. This is a good amateur level but no more than might be found in ordinary East Asian clubs. Published current European ratings would suggest around 100 players stronger than that, with very few European 7 ''dans''.}} Knowledge of the game has been scant elsewhere up until the 20th century. A famous player of the 1920s was ].{{efn|1=European Go has been documented by Franco Pratesi, ''Eurogo'' (Florence 2003) in three volumes, up to 1920, 1920–1950, and 1950 and later.}} It was not until the 1950s that more than a few Western players took up the game as other than a passing interest. In 1978, ] became the first Westerner to receive a professional player's certificate from an East Asian professional Go association.<ref name=wimmer>{{Citation | url = https://www.britgo.org/bgj/04112.html | title =Wimmer, Kerwin, Make Professional Shodan | publisher = British Go Association | access-date = 2008-06-11}}</ref> In 2000, American ] became the first Western player to achieve a 9 dan rank. | |||
== Equipment == | |||
{{Main|Go equipment}} | |||
] | |||
It is possible to play Go with a simple paper board and coins, plastic tokens, or white beans and coffee beans for the stones; or even by drawing the stones on the board and erasing them when captured. More popular midrange equipment includes cardstock, a ]d ], or wood boards with stones of plastic or glass. More expensive traditional materials are still used by many players. The most expensive Go sets have black stones carved from slate and white stones carved from translucent white shells (traditionally '']''), played on boards carved in a single piece from the trunk of a tree. | |||
=== Traditional equipment === | |||
] | |||
==== Boards ==== | |||
The ] (generally referred to by its Japanese name ''goban'' {{nihongo2|碁盤}}) typically measures between {{convert|45|and|48|cm|abbr=on}} in length (from one player's side to the other) and {{convert|42|to|44|cm|1|frac=4|abbr=on}} in width. Chinese boards are slightly larger, as a traditional Chinese Go stone is slightly larger to match. The board is not square; there is a 15:14 ratio in length to width, because with a perfectly square board, from the player's viewing angle the perspective creates a foreshortening of the board. The added length compensates for this.{{sfn|Fairbairn|1992|pp=142–143}} There are two main types of boards: a table board similar in most respects to other gameboards like that used for chess, and a floor board, which is its own free-standing table and at which the players sit. | |||
The traditional Japanese ''goban'' is between {{convert|10|and|18|cm|abbr=on}} thick and has legs; it sits on the floor (see picture).{{sfn|Fairbairn|1992|pp=142–143}} It is preferably made from the rare golden-tinged ] tree (''Torreya nucifera''), with the very best made from Kaya trees up to 700 years old. More recently, the related ] (''Torreya californica'') has been prized for its light color and pale rings as well as its reduced expense and more readily available stock. The natural resources of Japan have been unable to keep up with the enormous demand for the slow-growing Kaya trees; both ''T. nucifera'' and ''T. californica'' take many hundreds of years to grow to the necessary size, and they are now extremely rare, raising the price of such equipment tremendously.{{sfn|Fairbairn|1992|pp=143–149}} As Kaya trees are a protected species in Japan, they cannot be harvested until they have died. Thus, an old-growth, floor-standing Kaya ''goban'' can easily cost in excess of ]10,000 with the highest-quality examples costing more than $60,000.<ref>{{citation | url=http://www.kiseido.com/go_equipment.htm | title = Kiseido clearance sale}} lists the regular price for a Shihomasa Kaya Go Board with legs ({{convert|20.4|cm|abbr=on|disp=or}} thick) as $60,000+</ref> | |||
Other, less expensive woods often used to make quality table boards in both Chinese and Japanese dimensions include ] (''Thujopsis dolabrata''), ] (''Cercidiphyllum japonicum''), ] (''Agathis''), and Shin Kaya (various varieties of ], commonly from Alaska, Siberia and China's ]).{{sfn|Fairbairn|1992|pp=143–149}} So-called ''Shin Kaya'' is a potentially confusing merchant's term: ''shin'' means 'new', and thus ''shin kaya'' is best translated 'faux kaya', because the woods so described are biologically unrelated to Kaya.{{sfn|Fairbairn|1992|pp=143–149}} | |||
==== Stones ==== | |||
A full set of Go stones (''goishi'') usually contains 181 black stones and 180 white ones; a 19×19 grid has 361 points, so there are enough stones to cover the board, and Black gets the extra odd stone because that player goes first. However it may happen, especially in beginners' games, that many back-and-forth captures empty the bowls before the end of the game: in that case an exchange of prisoners allows the game to continue. | |||
Traditional Japanese stones are double-convex, and made of ]shell (white) and ] (black).{{sfn|Fairbairn|1992|pp=150–153}} The classic slate is nachiguro stone mined in ] and the clamshell from the Hamaguri clam ('']'') or the ]; however, due to a scarcity in the Japanese supply of these clams, the stones are most often made of shells harvested from ].{{sfn|Fairbairn|1992|pp=150–153}} Historically, the most prized stones were made of ], often given to the reigning emperor as a gift.{{sfn|Fairbairn|1992|pp=150–153}} | |||
In China, the game is traditionally played with single-convex stones{{sfn|Fairbairn|1992|pp=150–153}} made of a composite called ]. The material comes from Yunnan Province and is made by ] a proprietary and trade-secret mixture of mineral compounds derived from the local stone. This process dates to the Tang dynasty and, after the knowledge was lost in the 1920s during the ], was rediscovered in the 1960s by the now state-run Yunzi company. The material is praised for its colors, its pleasing sound as compared to glass or to synthetics such as ], and its lower cost as opposed to other materials such as slate/shell. The term ''yunzi'' can also refer to a single-convex stone made of any material; however, most English-language Go suppliers specify Yunzi as a material and single-convex as a shape to avoid confusion, as stones made of Yunzi are also available in double-convex while synthetic stones can be either shape. | |||
Traditional stones are made so that black stones are slightly larger in diameter than white; this is to compensate for the optical illusion created by contrasting colors that would make equal-sized white stones appear larger on the board than black stones.{{sfn|Fairbairn|1992|pp=150–153}}{{efn|1=See ] in Western typography for similar subtle adjustment to create a uniform appearance.}} | |||
] material, and the bowls of jujube wood.]] | |||
==== Bowls ==== | |||
The bowls for the stones are shaped like a flattened sphere with a level underside.{{sfn|Fairbairn|1992|pp=153–155}} The lid is loose fitting and upturned before play to receive stones captured during the game. Chinese bowls are slightly larger, and a little more rounded, a style known generally as ''Go Seigen''; Japanese ''Kitani'' bowls tend to have a shape closer to that of the bowl of a ] glass, such as for ]. The bowls are usually made of turned wood. ] is the traditional material for Japanese bowls, but is very expensive; wood from the Chinese ] date tree, which has a lighter color (it is often stained) and slightly more visible grain pattern, is a common substitute for rosewood, and traditional for Go Seigen-style bowls. Other traditional materials used for making Chinese bowls include ]ed wood, ]s, stone and woven straw or ]. The names of the bowl shapes, ''Go Seigen'' and ''Kitani'', were introduced in the last quarter of the 20th century by the professional player ] as homage to two 20th-century professional Go players by the same names, of Chinese and Japanese nationality, respectively, who are referred to as the "Fathers of modern Go".<ref name=jowa.html>{{cite web|first=John|last=Fairbairn|title=MindZine – Go – Feature: Honinbo Jowa|publisher=Mind Sports WorldWide|url= http://www.msoworld.com/mindzine/news/orient/go/history/jowa.html|access-date=15 May 2014|archive-url= https://web.archive.org/web/20110608002240/http://www.msoworld.com/mindzine/news/orient/go/history/jowa.html|archive-date=8 June 2011}}</ref> | |||
=== Playing technique and etiquette === | |||
] | |||
The traditional way to place a Go stone is to first take one from the bowl, gripping it between the index and middle fingers, with the middle finger on top, and then placing it directly on the desired intersection.<ref name="style">{{Citation|publisher=] |url=http://www.nihonkiin.or.jp/lesson/knowledge-e/uchikata-e.htm |title=A stylish way to play your stones |access-date=2007-02-24 |url-status=dead |archive-url=https://web.archive.org/web/20070513214109/http://www.nihonkiin.or.jp/lesson/knowledge-e/uchikata-e.htm |archive-date=2007-05-13}}</ref> One can also place a stone on the board and then slide it into position under appropriate circumstances (where it does not move any other stones). It is considered respectful towards White for Black to place the first stone of the game in the upper right-hand corner.<ref>{{cite web|url=http://senseis.xmp.net/?PlayingTheFirstMoveInTheUpperRightCorner |title=Sensei's Library: Playing the first move in the upper right corner |publisher=Senseis.xmp.net |date=2011-09-19 |access-date=2014-03-25}}</ref> (Because of symmetry, this has no effect on the game's outcome.) | |||
It is considered poor manners to run one's fingers through one's bowl of unplayed stones, as the sound, however soothing to the player doing this, can be disturbing to one's opponent. Similarly, clacking a stone against another stone, the board, or the table or floor is also discouraged. However, it is permissible to emphasize select moves by striking the board more firmly than normal, thus producing a sharp clack. Additionally, hovering one's arm over the board (usually when deciding where to play) is also considered rude as it obstructs the opponent's view of the board. | |||
Manners and etiquette are extensively discussed in 'The Classic of WeiQi in Thirteen Chapters', a ] manual to the game. Apart from the points above it also points to the need to remain calm and honorable, in maintaining posture, and knowing the key specialised terms, such as titles of common formations. Generally speaking, much attention is paid to the etiquette of playing, as much as to winning or actual game technique. | |||
== Computers and Go == | |||
{{Main|Computer Go}} | |||
=== Software players === | |||
Go long posed a daunting challenge to ]s, putting forward "difficult decision-making tasks, an intractable search space, and an optimal solution so complex it appears infeasible to directly approximate using a policy or value function".<ref name="AlphaGo" /> Prior to 2015,<ref name="AlphaGo">{{Cite journal|title = Mastering the game of Go with deep neural networks and tree search|journal = ]| issn= 0028-0836|pages = 484–489|volume = 529|issue = 7587|doi = 10.1038/nature16961|pmid = 26819042|first1 = David|last1 = Silver|author-link1=David Silver (programmer)|first2 = Aja|last2 = Huang|author-link2=Aja Huang|first3 = Chris J.|last3 = Maddison|first4 = Arthur|last4 = Guez|first5 = Laurent|last5 = Sifre|first6 = George van den|last6 = Driessche|first7 = Julian|last7 = Schrittwieser|first8 = Ioannis|last8 = Antonoglou|first9 = Veda|last9 = Panneershelvam|first10= Marc|last10= Lanctot|first11= Sander|last11= Dieleman|first12=Dominik|last12= Grewe|first13= John|last13= Nham|first14= Nal|last14= Kalchbrenner|first15= Ilya|last15= Sutskever|author-link15=Ilya Sutskever|first16= Timothy|last16= Lillicrap|first17= Madeleine|last17= Leach|first18= Koray|last18= Kavukcuoglu|first19= Thore|last19= Graepel|first20= Demis |last20=Hassabis|author-link20=Demis Hassabis|date= 28 January 2016|bibcode = 2016Natur.529..484S|s2cid = 515925}}{{closed access}}</ref> the best Go programs only managed to reach ] level.<ref name=humancomputermatchs>{{cite web|last=Wedd|first=Nick|title=Human-Computer Go Challenges|url=http://www.computer-go.info/h-c/index.html|work=computer-go.info|access-date=2011-10-28}}</ref> On smaller 9×9 and 13x13 boards, computer programs fared better, and were able to compare to professional players. Many in the field of ] consider Go to require more elements that mimic human thought than ].<ref>{{Citation| url=https://query.nytimes.com/gst/fullpage.html?res=9C04EFD6123AF93AA15754C0A961958260 | title=To Test a Powerful Computer, Play an Ancient Game | last=Johnson | first=George | work=]| date=1997-07-29 | access-date = 2008-06-16}}</ref> | |||
] | |||
The reasons why computer programs had not played Go at the ] level prior to 2016 include:<ref>{{Citation |url=http://www.intelligentgo.org/en/computer-go/overview.html |publisher=Intelligent Go Foundation |title=Overview of Computer Go |access-date=2008-06-16 |archive-url=https://web.archive.org/web/20080531072850/http://www.intelligentgo.org/en/computer-go/overview.html |archive-date=2008-05-31 |url-status=dead}}</ref> | |||
* The number of spaces on the board is much larger (over five times the number of spaces on a chess board—361 vs. 64). On most turns there are many more possible moves in Go than in chess. Throughout most of the game, the number of legal moves stays at around 150–250 per turn, and rarely falls below 100 (in chess, the average number of moves is 37).<ref>{{citation | title = How to beat your chess computer | first1 = Raymond | last1 = Keene | first2 = David | last2 = Levy | publisher = Batsford Books | year = 1991 | page = 85}}</ref> Because an ] for Go must calculate and compare every possible legal move in each ] (player turn), its ability to calculate the best plays is sharply reduced when there are a large number of possible moves. Most computer game algorithms, such as those for chess, compute several moves in advance. Given an average of 200 available moves through most of the game, for a computer to calculate its next move by exhaustively anticipating the next four moves of each possible play (two of its own and two of its opponent's), it would have to consider more than 320 billion (3.2{{e|11}}) possible combinations. To exhaustively calculate the next eight moves, would require computing 512 quintillion (5.12{{e|20}}) possible combinations. {{As of|2014|3}}, the most powerful supercomputer in the world, ]'s "]", can sustain 33.86 ].<ref>{{cite web | |||
|url=https://spectrum.ieee.org/tianhe2-caps-top-10-supercomputers | |||
|title=China's Tianhe-2 Caps Top 10 Supercomputers | |||
|access-date=2014-04-14 | |||
|author=Davey Alba | |||
|author-link=Davey Alba | |||
|date=2014-06-17 | |||
|publisher=IEEE Spectrum | |||
}}</ref> At this rate, even given an exceedingly low estimate of 10 operations required to assess the value of one play of a stone, Tianhe-2 would require four hours to assess all possible combinations of the next eight moves in order to make a single play. | |||
* The placement of a single stone in the initial phase can affect the play of the game a hundred or more moves later. A computer would have to predict this influence, and it would be unworkable to attempt to exhaustively analyze the next hundred moves. | |||
* In capture-based games (such as chess), a position can often be evaluated relatively easily, such as by calculating who has a material advantage or more active pieces.{{efn|1=While chess position evaluation is simpler than Go position evaluation, it is still more complicated than simply calculating material advantage or piece activity; pawn structure and king safety matter, as do the possibilities in further play. The complexity of the algorithm differs per engine.<ref>{{citation|last=Shannon|first=Claude|year=1950|title=Programming a Computer for Playing Chess|publisher=Philosophical Magazine|series=Ser. 7|volume=41|issue=314|url=https://archive.computerhistory.org/projects/chess/related_materials/text/2-0%20and%202-1.Programming_a_computer_for_playing_chess.shannon/2-0%20and%202-1.Programming_a_computer_for_playing_chess.shannon.062303002.pdf|access-date=12 December 2021}}</ref><ref>{{citation|title=Learning to Play the Game of Chess|last=Thurn|first=Sebastian|year=1995|publisher=MIT Press|url=https://proceedings.neurips.cc/paper/1994/file/d7322ed717dedf1eb4e6e52a37ea7bcd-Paper.pdf|access-date=12 December 2021}}</ref><ref>{{citation|title=A Self-Learning, Pattern-Oriented Chess Program|last=Levinson|first=Robert|year=1989|publisher=ICCA Journal|volume=12|issue=4}}</ref>}} In Go, there is often no easy way to evaluate a position.<ref name=research.microsoft.com>{{cite web|last=Stern|first=David|title=Modelling Uncertainty in the Game of Go|url=http://www.cs.brown.edu/~ynm/Papers/AAAI06-312.pdf|work=]|access-date=15 May 2014|archive-url=https://web.archive.org/web/20130525131512/http://cs.brown.edu/~ynm/Papers/AAAI06-312.pdf|archive-date=25 May 2013}}</ref> However a 6-kyu human can evaluate a position at a glance, to see which player has more territory, and even beginners can estimate the score within 10 points, given time to count it. The number of stones on the board (material advantage) is only a weak indicator of the strength of a position, and a territorial advantage (more empty points surrounded) for one player might be compensated by the opponent's strong positions and influence all over the board. Normally a 3-dan can easily judge most of these positions. | |||
It was not until August 2008 that a computer won a game against a professional level player at a handicap of 9 stones, the greatest handicap normally given to a weaker opponent. It was the Mogo program, which scored this first victory in an exhibition game played during the US Go Congress.<ref>{{cite web| title= Supercomputer with innovative software beats Go Professional| url= http://www.cs.unimaas.nl/g.chaslot/muyungwan-mogo/| access-date= 2008-12-19| url-status= dead| archive-url= https://web.archive.org/web/20090101023512/http://www.cs.unimaas.nl/g.chaslot/muyungwan-mogo/| archive-date= 2009-01-01}}</ref><ref>{{cite web | title= AGA News: Kim Prevails Again In Man Vs Machine Rematch | url=http://www.usgo.org/news/ | access-date = 2009-08-08}}</ref> By 2013, a win at the professional level of play was accomplished with a four-stone advantage.<ref>{{Cite magazine|url = https://www.wired.com/2014/05/the-world-of-computer-go/|title = The Mystery of Go, the Ancient Game That Computers Still Can't Win|last = Levinovitz|first = Alan|date = May 12, 2014|magazine = Wired|access-date = December 8, 2015|department = Business|at = The Electric Sage Battle}}</ref><ref>{{Cite magazine|url = https://www.wired.com/2015/12/google-and-facebook-race-to-solve-the-ancient-game-of-go|title = Google and Facebook Race To Solve the Ancient Game of Go With AI|last = Metz|first = Cade|date = December 7, 2015|magazine = Wired|access-date = December 8, 2015|department = Business}}</ref> In October 2015, ]'s program ] beat ], the European Go champion and a ] (out of 9 dan possible) professional, ] with no handicap on a full size 19×19 board.<ref name="AlphaGo" /> AlphaGo used a fundamentally different paradigm than earlier Go programs; it included very little direct instruction, and mostly used ] where AlphaGo played itself in hundreds of millions of games such that it could measure positions more intuitively. In March 2016, Google next challenged ], a 9 dan considered the top player in the world in the early 21st century,<ref>{{ cite web|title= History of Go Ratings |url= http://www.goratings.org/history/ |author=<!--Staff writer(s); no by-line.--> |website= goratings.org |access-date= 18 March 2016}}</ref> to a ]. Leading up to the game, Lee Sedol and other top professionals were confident that he would win;<ref>{{cite web|title= Lee Se-dol confident about beating AlphaGo |url= https://www.koreatimes.co.kr/www/news/tech/2016/03/325_199865.html |author=<!--Staff writer(s); no by-line.--> |website= ] |date= 8 March 2016 |access-date= 18 March 2016}}</ref> however, AlphaGo defeated Lee in four of the five games.<ref name="BBC News 12 March 2016">{{cite web | title= Artificial intelligence: Google's AlphaGo beats Go master Lee Se-dol |url= https://www.bbc.co.uk/news/technology-35785875| author=<!--Staff writer(s); no by-line.-->|date= 12 March 2016| website= ] | access-date= 12 March 2016}}</ref><ref>{{cite news|last1=Lawler|first1=Richard|title=Google DeepMind AI wins final Go match for 4-1 series win|url=https://www.engadget.com/2016/03/14/the-final-lee-sedol-vs-alphago-match-is-about-to-start/|access-date=15 March 2016}}</ref> After having already lost the series by the third game, Lee won the fourth game, describing his win as "invaluable".<ref name="BBC News 13 March 2016">{{cite web | title= Artificial intelligence: Go master Lee Se-dol wins against AlphaGo program |url= https://www.bbc.co.uk/news/technology-35797102| author=<!--Staff writer(s); no by-line.-->|date= 13 March 2016| website= ] | access-date= 13 March 2016}}</ref> In May 2017, AlphaGo beat ], who at the time continuously held the world No. 1 ranking for two years,<ref>{{Cite web|title=柯洁迎19岁生日 雄踞人类世界排名第一已两年|url=http://sports.sina.com.cn/go/2016-08-02/doc-ifxunyya3020238.shtml|language=zh|date=May 2017}}</ref><ref>{{Cite web|url=http://www.goratings.org/|title=World's Go Player Ratings|date=24 May 2017}}</ref> winning each game in a ] during the ].<ref name="wuzhensecond">{{cite magazine|url=https://www.wired.com/2017/05/googles-alphago-continues-dominance-second-win-china/|title=Google's AlphaGo Continues Dominance With Second Win in China|magazine=Wired|date=2017-05-25}}</ref><ref>{{cite magazine|url=https://www.wired.com/2017/05/win-china-alphagos-designers-explore-new-ai/|title=After Win in China, AlphaGo's Designers Explore New AI|magazine=Wired|date=2017-05-27}}</ref> In October 2017, ] announced a significantly stronger version called ] which beat the previous version by 100 games to 0.<ref>{{cite journal |first1=David |last1=Silver|author-link1=David Silver (programmer)|first2= Julian|last2= Schrittwieser|first3= Karen|last3= Simonyan|first4= Ioannis|last4= Antonoglou|first5= Aja|last5= Huang|author-link5=Aja Huang|first6=Arthur|last6= Guez|first7= Thomas|last7= Hubert|first8= Lucas|last8= Baker|first9= Matthew|last9= Lai|first10= Adrian|last10= Bolton|first11= Yutian|last11= Chen|author-link11=Chen Yutian|first12= Timothy|last12= Lillicrap|first13=Hui|last13= Fan|author-link13=Fan Hui|first14= Laurent|last14= Sifre|first15= George van den|last15= Driessche|first16= Thore|last16= Graepel|first17= Demis|last17= Hassabis |author-link17=Demis Hassabis|title=Mastering the game of Go without human knowledge|journal=]|issn= 0028-0836|pages=354–359|volume =550|issue =7676|doi =10.1038/nature24270|pmid=29052630|date=19 October 2017|bibcode=2017Natur.550..354S|s2cid=205261034|url=https://discovery.ucl.ac.uk/id/eprint/10045895/1/agz_unformatted_nature.pdf|archive-url=https://web.archive.org/web/20200102034116/https://discovery.ucl.ac.uk/id/eprint/10045895/1/agz_unformatted_nature.pdf|archive-date=2 January 2020|url-status=live}}{{closed access}}</ref> | |||
In February 2023, Kellin Pelrine, an amateur American Go player, won 14 out of 15 games against a top-ranked AI system in a significant victory over artificial intelligence. Pelrine took advantage of a previously unknown flaw in the Go computer program, which had been identified by another computer. He exploited this weakness by slowly encircling the opponent's stones and distracting the AI with moves in other parts of the board. The tactics used by Pelrine have highlighted a fundamental flaw in the deep learning systems that underpin many of today's advanced AI. Although the AI systems can "understand" specific situations, they lack the ability to generalize in a way that humans find easy.<ref>{{Cite news |author1=Joshua Wolens |date=2023-02-20 |title=A human has beat an AI in possibly the most complex board game ever |language=en |work=PC Gamer |url=https://www.pcgamer.com/a-human-has-beat-an-ai-in-possibly-the-most-complex-board-game-ever/ |access-date=2023-02-21}}</ref><ref>{{Cite web |title=Human convincingly beats AI at Go with help from a bot |url=https://www.engadget.com/human-convincingly-beats-ai-at-go-with-help-from-a-bot-100903836.html |access-date=2023-02-21 |website=Engadget |date=20 February 2023 |language=en-US}}</ref><ref>{{Cite web |last=Times |first=Financial |date=2023-02-19 |title=Man beats machine at Go in human victory over AI |url=https://arstechnica.com/information-technology/2023/02/man-beats-machine-at-go-in-human-victory-over-ai/ |access-date=2023-02-21 |website=Ars Technica |language=en-us}}</ref> | |||
=== Software assistance === | |||
{{Main|Go software}} | |||
] | |||
An abundance of software is available to support players of the game. This includes programs that can be used to view or edit game records and diagrams, programs that allow the user to search for patterns in the games of strong players, and programs that allow users to play against each other over the Internet. | |||
Some web servers{{Citation needed|date=January 2015}} provide graphical aids like maps, to aid learning during play. These graphical aids may suggest possible next moves, indicate areas of influence, highlight vital stones under attack and mark stones in atari or about to be captured. | |||
There are several file formats used to store game records, the most popular of which is SGF, short for ]. Programs used for editing game records allow the user to record not only the moves, but also variations, commentary and further information on the game.{{efn|1=Lists of such programs may be found at or .}} | |||
Electronic databases can be used to study life and death situations, ], ] and games by a particular player. Programs are available that give players pattern searching options, which allow players to research positions by searching for high-level games in which similar situations occur. Such software generally lists common follow-up moves that have been played by professionals and gives statistics on win–loss ratio in opening situations. | |||
Internet-based ] allow access to competition with players all over the world, for real-time and turn-based games.{{efn|1=Lists of Go servers are kept at and }} Such servers also allow easy access to professional teaching, with both teaching games and interactive game review being possible.{{efn|1=The British Go Association provides a }} | |||
== In popular culture == | |||
] by ], 1886. This popular woodblock print depicts the ancient legend of a husband who suspected his wife was having an affair with the samurai Minamoto no Yoshiie. To prevent his visits, the husband surrounded his house with brambles and placed a Go board on the balcony, hoping he would stumble over it. Instead, the samurai deftly cut the board as he leaped over the balcony railing, avoiding both obstacles.]] | |||
Apart from technical literature and study material, Go and its strategies have been the subject of several works of fiction, such as '']'' by ]-winning author ]{{efn|1=A list of books can be found at }} and '']'' by Shan Sa. Other books have used Go as a ] or minor plot device. For example, the novel '']'' by ] centers around the game and uses Go metaphors.<ref name=GoLit>{{Citation | title = Go in Western Literature | chapter = Shibumi | last = McDonald | first = Brian | orig-year = 1995 | year = 2002 | chapter-url = http://www.usgo.org/resources/downloads/go_in_literature.pdf | publisher = American Go Association | pages = 5–6 | editor = Shotwell, Peter | access-date = 2008-06-16|archive-url=https://web.archive.org/web/20060921171349/http://www.usgo.org/resources/downloads/go_in_literature.pdf|archive-date=2006-09-21}}</ref> {{sfn|Shotwell|2003|p=176}} Go features prominently in the '']'' series of novels by ], being the favourite game of the main villain.<ref>{{cite web|url=https://www.britgo.org/general/novels |title=Novels and Other Books Featuring Go | British Go Association |publisher=Britgo.org |date=2015-12-16 |access-date=2016-03-14}}</ref> | |||
The ] series '']'' and its ] adaptation, first released in Japan in 1998 and 2001 respectively, had a large impact in popularizing Go among young players, both in Japan and—as translations were released—abroad.<ref>{{Citation|first=Yoko |last=Shimatsuka |title=Do Not Pass Go |url=http://www.asiaweek.com/asiaweek/magazine/nations/0,8782,132162,00.html |publisher=Asiaweek |access-date=2007-03-26 |archive-url=https://web.archive.org/web/20070610073841/http://www.asiaweek.com/asiaweek/magazine/nations/0%2C8782%2C132162%2C00.html |archive-date=2007-06-10 |url-status=dead}}</ref><ref>{{cite news | first=Charles | last=Scanlon | title=Young Japanese go for Go | date=2002-08-01 | publisher=BBC | url =http://news.bbc.co.uk/2/hi/asia-pacific/2164532.stm | work =World News | access-date = 2009-05-21}}</ref><!-- Please do not add material to this section unless you feel it is at least as significant as Hikaru no Go. There are literally hundreds of books, films and TV series that feature Go somewhere, there is simply no room to list them all --> | |||
Similarly, Go has been used as a subject or plot device in film, such as '']'', '']'', '']'', '']'', and '']'' (a ] of Go professional ]).<ref>{{Citation | url=https://query.nytimes.com/gst/fullpage.html?res=9D03EFDC1131F937A25750C0A9619C8B63&scp=1&sq=%22The+Go+Master%22&st=nyt | title=A Prodigy's Life Is Played Out In a Japanese Game of Skill |work=] |last=Scott |first=A.O. |date=2007-03-14 | access-date = 2008-06-16}}</ref>{{efn|1=A list of films can be found at the }} 2013's ''Tôkyô ni kita bakari'' or ''Tokyo Newcomer'' portrays a Chinese foreigner Go player moving to Tokyo.<ref>(film; 2013) Tokyo Newcomer</ref> In ]'s ] film '']'', the characters are color-coded as Go stones (black or other dark shades for the Chinese, white for the Japanese invaders), Go boards and stones are used by the characters to keep track of soldiers prior to battle, and the battles themselves are structured like a game of Go.<ref>{{Citation |author= Ng Ho |editor-first=Stephen |editor-last=Teo |series=Hong Kong International Film Festival |title=Transcending the Times:King Hu & Eileen Chan |publisher=Provisional Urban Council of Hong Kong |year=1998 |location=Hong Kong |page=45 |chapter=King Hu and the Aesthetics of Space}}</ref> | |||
Go has also been featured as a plot device in a number of television series. Examples include ]'s ] ] '']'', which is rich in references (the opening itself featuring developments on a Go board), and includes Go matches, accurately played, relevant to the plot.<ref name="BritGoSeries">{{Citation | url=https://www.britgo.org/filmography/tv | title=Go Filmography - Television Dramas | British Go Association | publisher=Britgo.org |date=2007-03-14 | access-date = 2018-12-25}}</ref> Also, in 2024 ] released the historical-fictional Korean series '']''. | |||
The corporation and brand ] was named after the ].<ref name="Atari and Go">{{cite web| title = The Rise and Fall of Atari | date=5 May 2008| url=http://www.neatorama.com/2008/05/05/the-rise-and-fall-of-atari/| access-date = May 5, 2014}}</ref> | |||
Hedge fund manager ] used Go as his main investing metaphor in his investing book ''The Dao of Capital''.<ref>{{cite book |first=Mark |last=Spitznagel |title=The Dao of Capital: Austrian Investing in a Distorted World |publisher=John Wiley & Sons |year=2013 |isbn=978-1-118-34703-4}}</ref> ''The Way of Go: 8 Ancient Strategy Secrets for Success in Business and Life'' by Troy Anderson applies Go strategy to business.<ref name=WayOfGo>{{Citation | title = The Way of Go: 8 Ancient Strategy Secrets for Success in Business and Life | last = Anderson | first = Troy | date=August 3, 2004}}</ref> ''GO: An Asian Paradigm for Business Strategy''<ref>{{Citation | last = Yasuyuki | first = Miura | title = Go, an Asian Paradigm for Business Strategy | year = 1998 | publisher = Kiseido Publishing Company | isbn = 978-4-906574-99-5}}</ref> by Miura Yasuyuki, a manager with Japan Airlines,<ref>{{Citation | url = http://www.yomiuri.co.jp/igo_e/033.htm | archive-url = https://archive.today/20041209075324/http://www.yomiuri.co.jp/igo_e/033.htm | url-status = dead | archive-date = 2004-12-09 | title = The Magic of Go – 33. Go and business (1) | publisher = ] | last = Bozulich | first = Richard | access-date = 2013-11-27}}</ref> uses Go to describe the thinking and behavior of business men. | |||
== Psychological perspectives == | |||
A 2004 review of literature by ], de Voogt and ] shows that relatively little scientific research has been carried out on the ] of Go, compared with other traditional board games such as ].<ref name="Moves in mind">{{citation | last1= Gobet | first1 = F | last2 = de Voogt | first2 = A. J | last3 = Retschitzki | first3 = J |year = 2004 | title = Moves in Mind: The Psychology of Board Games | publisher = Hove, UK: Psychology Press | isbn = 978-1-84169-336-1 |url=https://books.google.com/books?id=fR7xZlGnyl0C}}</ref> Computer Go research has shown that given the large search tree, knowledge and pattern recognition are more important in Go than in other strategy games, such as chess.<ref name="Moves in mind" /> A study of the effects of age on Go-playing<ref>{{Citation | last1 = Masunaga | first1 = H | last2 = Horn | first2 =J. |year = 2001 | journal = Psychology and Aging | issue = 2 | pages = 293–311 | title = Expertise and age-related changes in components of intelligence | doi = 10.1037/0882-7974.16.2.293 | pmid = 11405317 | volume = 16 | issn=0882-7974}}</ref> has shown that mental decline is milder with strong players than with weaker players. According to the review of Gobet and colleagues, the pattern of brain activity observed with techniques such as ] and ] does not show large differences between Go and chess. On the other hand, a study by Xiangchuan Chen et al.<ref>{{citation | author = Chen | journal = Cognitive Brain Research | title = A functional MRI study of high-level cognition II. The game of GO | year = 2003 | doi = 10.1016/S0926-6410(02)00206-9 |pmid = 12589886| volume = 16 |issue = 1|pages = 32–7| display-authors = etal}}</ref> showed greater activation in the right hemisphere among Go players than among chess players, but the research was inconclusive because strong players from Go were hired while very weak chess players were hired in the original study.<ref>{{Cite journal |last1=Atherton |first1=Michael |last2=Zhuang |first2=Jiancheng |last3=Bart |first3=William M |last4=Hu |first4=Xiaoping |last5=He |first5=Sheng |date=March 2003 |title=A functional MRI study of high-level cognition. I. The game of chess |url=https://linkinghub.elsevier.com/retrieve/pii/S0926641002002070 |journal=Cognitive Brain Research |language=en |volume=16 |issue=1 |pages=26–31 |doi=10.1016/S0926-6410(02)00207-0|pmid=12589885 }}</ref> There is some evidence to suggest a correlation between playing board games and reduced risk of ] and ].<ref>{{citation | author = Verghese | title = Leisure Activities and the Risk of Dementia in the Elderly | journal =] | pmid = 12815136 | doi = 10.1056/NEJMoa022252 | year = 2003 | volume = 348 | pages = 2508–16 | last2 = Lipton | first2 = RB | last3 = Katz | first3 = MJ | last4 = Hall | first4 = CB | last5 = Derby | first5 = CA | last6 = Kuslansky | first6 = G | last7 = Ambrose | first7 = AF | last8 = Sliwinski | first8 = M | last9 = Buschke | first9 = H | issue = 25 | display-authors = 1| doi-access = free }}</ref> | |||
Arthur Mary, a French researcher in clinical ], reports on his psychotherapeutic approaches using the game of Go with patients in private practice and in a psychiatric ward.<ref>{{citation | last = Mary | first = Arthur | title = Le jeu de go, une voie royale vers l'inconscient | year = 2024 |publisher = L'Harmattan}}</ref> Drawing on ] research and employing a ] (]) and ] approach, he demonstrates how ] are expressed on the goban.<ref>{{Cite journal |last=Mary |first=arthur |date=2020 |title=Eros et Thanatos autour du goban |journal=Revue française de go |language=fr |issue=151 }}</ref> He offers some suggestions to therapists for defining ways of playing go that lead to therapeutic effects.<ref>{{Cite journal |last=Mary |first=arthur |date=2022 |title=Sous le plateau de go, ce je qui vague |journal=Une praxis de la psychanalyse |publisher = L'Harmattan |language=fr }}</ref> | |||
== Analyses of the game == | |||
{{See also|Go and mathematics}} | |||
In formal ] terms, Go is a non-chance, ] with ]. Informally that means there are no dice used (and decisions or moves create discrete outcome vectors rather than probability distributions), the underlying math is combinatorial, and all moves (via single vertex analysis) are visible to both players (unlike some card games where some information is hidden). Perfect information also implies sequence—players can theoretically know about all past moves. | |||
Other game theoretical taxonomy elements include the facts | |||
*Go is bounded by a finite number of moves and every game must end with a victor or a tie (although ties are very rare); | |||
*the strategy is associative because every strategy is a function of board position; | |||
*the format is non-cooperative (that is, it's not a team sport); | |||
*positions are extensible, and so can be represented by board position trees; | |||
*the game is ] because player choices do not increase resources available, the rewards in the game are fixed and if one player wins, the other loses, and the utility function is restricted (in the sense of win/lose); | |||
*however, ratings, monetary rewards, national and personal pride and other factors can extend utility functions, but generally not to the extent of removing the win/lose restriction, although ]s can theoretically add non-zero and complex utility aspects even to two player games.<ref>{{cite book |first=Michael |last=Maschler |title=Game Theory |publisher=Cambridge University Press |year=2013 |isbn=978-1-107-00548-8}} {{page needed|date=May 2014}}</ref> | |||
In the endgame, it can often happen that the state of the board consists of several subpositions that do not interact with the others. The whole board position can then be considered as a mathematical sum, or composition, of the individual subpositions.{{sfn|Moews|1996|p=259}} It is this property of Go endgames that led ] to the discovery of ]s.<ref name="O'Connor Robertson Conway">{{citation | url = http://www-history.mcs.st-andrews.ac.uk/Biographies/Conway.html | title = Conway Biography | last1 = O'Connor | first1 = J.J. | last2 = Robertson | first2 = E.F. | access-date = 2008-01-24}}</ref> | |||
In ] terms, Go is a ], ], ], ] ], putting it in the same class as chess, ] (checkers), and ] (Othello). | |||
The game emphasizes the importance of balance on multiple levels: to secure an area of the board, it is good to play moves close together; however, to cover the largest area, one needs to spread out, perhaps leaving weaknesses that can be exploited. Playing too ''low'' (close to the edge) secures insufficient territory and influence, yet playing too ''high'' (far from the edge) allows the opponent to invade. Decisions in one part of the board may be influenced by an apparently unrelated situation in a distant part of the board (for example, ladders can be broken by stones at an arbitrary distance away). Plays made early in the game can shape the nature of conflict a hundred moves later. | |||
The ] of Go is such that describing even elementary strategy fills many introductory books. In fact, numerical estimates show that the number of possible games of Go far exceeds ].{{efn|1=It has been said that the number of board positions is at most 3<sup>361</sup> (about 10<sup>172</sup>) since each position can be white, black, or vacant. Ignoring (illegal) suicide moves, there are at least 361! games (about 10<sup>768</sup>) since every permutation of the 361 points corresponds to a game. See ] for more details, which includes much larger estimates.<br>This estimate, however, is inexact for two reasons: first, both contestants usually agree to end the game long before every point has been played; second, after a capture it may happen that an already played point is played again, even repetitively so in the case of a kō-battle.}} | |||
Go also contributed to the development of ] (with Go infinitesimals<ref>{{Cite web|url=https://senseis.xmp.net/?GoInfinitesimals|title=Go Infinitesimals at Sensei's Library|website=senseis.xmp.net}}</ref> being a specific example of its use in Go). | |||
== Comparisons to other games == | |||
Go begins with an empty board. It is focused on building from the ground up (nothing to something) with multiple, simultaneous battles leading to a point-based win. Chess is tactical rather than strategic, as the predetermined strategy is to trap one individual piece (the king). This comparison has also been applied to military and political history, with ]'s book ''The Protracted Game'' (1969) and, more recently, ]'s book '']'' (1998) exploring the strategy of the ] in the ] through the lens of Go.<ref>{{Citation |last=Boorman |first=Scott A. |title=The Protracted Game: A Wei Ch'i Interpretation of Maoist Revolutionary Strategy |year=1969 |publisher=Oxford University Press |location=New York, NY |isbn = 978-0-19-500490-8}}</ref><ref>{{Citation |title = The 48 Laws of Power |chapter = Law 48: Assume Formlessness |last = Greene |first = Robert |year = 1998 |publisher = Viking Press |location = New York, NY |isbn = 978-0-670-88146-8 |url-access = registration |url = https://archive.org/details/isbn_9780670881468}}</ref> | |||
A similar comparison has been drawn among Go, ] and ], perhaps the three oldest games that enjoy worldwide popularity.<ref name="WPinc">{{cite book|last=Pinckard|first=William|chapter=Go and the Three Games|date=n.d.|chapter-url=http://www.kiseido.com/three.htm|access-date=2008-06-11|editor-last=Bozulich|editor-first=Richard|title=The Go Player's Almanac|publication-date=2001|edition=2nd|publisher=Kiseido Publishing Company|isbn=978-4-906574-40-7|archive-date=2019-09-05|archive-url=https://web.archive.org/web/20190905135104/http://www.kiseido.com/three.htm|url-status=dead}}</ref> Backgammon is a "man vs. fate" contest, with chance playing a strong role in determining the outcome. Chess, with rows of soldiers marching forward to capture each other, embodies the conflict of "man vs. man". Because the handicap system tells Go players where they stand relative to other players, an honestly ranked player can expect to lose about half of their games; therefore, Go can be seen as embodying the quest for self-improvement, "man vs. self".<ref name="WPinc" /> | |||
==See also== | |||
{{Portal|Go}} | |||
*] | |||
*] | |||
*] | |||
*] | |||
== Notes == | |||
{{notelist|30em}} | |||
== References == | |||
=== Citations === | |||
{{Reflist|20em}} | |||
=== Sources === | |||
{{refbegin|30em}} | |||
* {{Citation |first= Louis Victor |last= Allis |year= 1994 |title= Searching for solutions in Games and Artificial Intelligence |isbn= 978-90-9007488-7 |url= http://fragrieu.free.fr/SearchingForSolutions.pdf |publisher= Proefschrift Rijksuniversiteit Limburg |place= Maastricht |archive-url= https://web.archive.org/web/20050307024938/http://fragrieu.free.fr/SearchingForSolutions.pdf |archive-date= March 7, 2005 |url-status= live}} | |||
* {{cite book|editor-last=Bozulich|editor-first=Richard|title=The Go Player's Almanac|date=2001|edition=2nd|publisher=Kiseido Publishing Company|isbn=978-4-906574-40-7}} | |||
*{{Citation | last = Chen | first = Zuyuan | year = 2011 | title = The History of Go Rules | publisher = American Go Association | url = http://www.usgo.org/files/bh_library/Historyofgorules.pdf | access-date = May 7, 2014 | archive-url = https://web.archive.org/web/20130515112132/http://www.usgo.org/files/bh_library/historyofgorules.pdf | archive-date = May 15, 2013 | url-status = live}} | |||
* {{cite book|last=]|title=Go: A Complete Introduction to the Game|publisher=Kiseido Publishers|location=Tokyo|year=1997|isbn=978-4-906574-50-6}} | |||
* {{cite book|last=Cobb|first=William|title=The Book of Go|publisher=]|year=2002|isbn=978-0-8069-2729-9}} | |||
* {{cite book|last=Dahl|year=2001 |first=Fredrik A. |chapter=Honte, a Go-Playing Program Using Neural Nets |title=Machines That Learn To Play Games |editor1-last=Fürnkranz |editor1-first=Johannes |editor2-last=Kubat |editor2-first=Miroslav |publisher=Nova Science Publishers |location=Huntington, NY |isbn=1-59033-021-8 |pages=205–223 |citeseerx=10.1.1.50.2676}} | |||
* {{cite book|last=Davies|first=James|year=1995|title=Tesuji|series=Elementary Go Series|volume=3|publisher=Kiseido Publishing Company|location=Japan|edition=3rd|isbn=4-906574-12-2}} | |||
* {{cite book|last=Fairbairn|first=John|chapter=A Survey of the best in Go Equipment|year=1992|pages=142–155|editor-last=Bozulich|editor-first=Richard|title=The Go Player's Almanac|publication-date=2001|edition=2nd|publisher=Kiseido Publishing Company|isbn=978-4-906574-40-7}} | |||
* {{Citation | last = Fairbairn | first = John | url = http://www.pandanet.co.jp/English/essay/goancientchina.html | title = Go in Ancient China | year = 1995 | access-date = 2007-11-02}} | |||
* {{Citation |last=Fairbairn|first=John|year=2000|title=History of Go in Korea|url= http://www.msoworld.com/mindzine/news/orient/go/history/origin_korea.html|access-date=15 May 2014|archive-url= https://web.archive.org/web/20110608021308/http://www.msoworld.com/mindzine/news/orient/go/history/origin_korea.html|archive-date=8 June 2011}} | |||
*{{cite book|last=Fairbairn|first=John|year=2004|title=Invitation to Go|publisher=Dover Publications|location=United States|edition=2nd|isbn=0-486-43356-0|url=https://books.google.com/books?id=ndsoAwAAQBAJ}} | |||
*{{Citation | last1 = Fairbairn | first1 = John | last2 = Hall | first2 = T. Mark | title = The GoGoD Encyclopaedia | publisher = Games of Go on Disc (GoGoD) | year = 2007|url=https://gogodonline.co.uk/}} | |||
*{{cite book|last=Ishigure|first=Ikuro|year=2006|title=In the Beginning: the Opening in the game of Go|series=Elementary Go Series|volume=1|publisher=Kiseido Publishing Company|location=Japan|edition=8th|isbn=4-906574-10-6}} | |||
* {{cite book|author-link=Kaoru Iwamoto|last=Iwamoto|first=Kaoru|title=Go for Beginners|publisher=Pantheon|location=New York|year=1977|isbn=978-0-394-73331-9}} | |||
*{{cite book|last=Kageyama|first=Toshiro|author-link=Toshiro Kageyama|year=2007|title=Lessons in the Fundamentals of Go|publisher=Kiseido Publishing Company|location=Japan|edition=3rd|isbn=978-4-906574-28-5}} | |||
*{{cite book|last1=Kim|first1=Janice|author-link=Janice Kim|last2=Jeong|first2=Soo-hyun|title=Learn to Play Go|series=Five volumes|isbn=978-0-9644796-1-6|year=1997|edition=2nd|publisher=Good Move Press|location=New York, NY}} | |||
*{{cite book|last=Lasker|first=Edward|author-link=Edward Lasker|year=1960|title=Go and Go-Moku: the Oriental Board Games|url=https://archive.org/details/gogomokuoriental00lask|url-access=registration|publisher=Dover Publications, Inc.|location=New York|edition=2nd|isbn=0486-20613-0|lccn=60050074}} | |||
* {{Citation | last = Masayoshi | first = Shirakawa | publisher = Yutopian Enterprises | title =A Journey In Search of the Origins of Go | year = 2005 | isbn = 978-1-889554-98-3}} | |||
* {{Citation | url = http://nrich.maths.org/public/viewer.php?obj_id=1452 | first = Charles | last = Matthews | title = Sufficient but Not Necessary: Two Eyes and Seki in Go | publisher = University of Cambridge |date = September 2002 | access-date = 2007-12-31}} | |||
* {{cite book|last=Matthews|first=Charles|title=Teach Yourself Go|publisher=]|year=2004|isbn=978-0-07-142977-1}} | |||
*{{Citation | last = Moews | first = David | title = Games of No Chance | series = MRSI Publications | volume = 29 | year = 1996 | chapter = Loopy Games and Go | chapter-url = http://library.msri.org/books/Book29/files/moloopy.pdf | pages = 259–272 | url = http://library.msri.org/books/Book29/contents.html | archive-url = https://web.archive.org/web/20110410143450/http://library.msri.org/books/Book29/files/moloopy.pdf | archive-date = April 10, 2011 | url-status = live}} | |||
* {{Citation | last = Moskowitz| first = Marc L.| editor-last = Lent| editor-first = John| editor2-last = Fitzsimmons| editor2-first = Lorna| year = 2013| title = Asian Popular Culture | chapter = ''Weiqi'' Legends, then and now: Cultural Paradigms in the Game of Go| publisher = Lexington Books| place = United Kingdom| isbn = 978-0-7391-7961-1| url = https://books.google.com/books?id=OixuQqUWHbIC| access-date = May 9, 2014}} | |||
* {{citation|last1=Müller |first1=Martin |last2=Gasser |first2=Ralph |year=1996|name-list-style=amp |title=Games of No Chance: Combinatorial Games at MSRI, 1994 |editor-last=Nowakowski |editor-first=Richard J. |publisher=Cambridge University Press |isbn=0-521-64652-9 |pages=273–284 |chapter=Experiments in Computer Go Endgames |chapter-url=http://library.msri.org/books/Book29/files/muller.pdf |archive-url=https://web.archive.org/web/20110410143455/http://library.msri.org/books/Book29/files/muller.pdf |archive-date=April 10, 2011 |url-status=live}} | |||
*{{cite book|last=Nihon Kiin|author-link=Nihon Ki-in|year=1973|title=Go: the World's most Fascinating Game|publisher=Nihon Kiin|location=Tokyo, Japan|edition=1st}} | |||
**Vol. 1: Introduction {{OCLC|926865835}} | |||
**Vol. 2: Basic techniques {{OCLC|59692609}} | |||
*{{cite book|last=Otake|first=Hideo|author-link=Hideo Otake|year=2002|title=Opening Theory Made Easy: Twenty Strategic Principles to Improve Your Opening Game|publisher=Kiseido Publishing Company|location=Tokyo|edition=6th|isbn=978-4-906574-36-0}} | |||
* {{cite magazine|last1=Peng|first1=Mike|last2=Hall|first2=Mark|title=One Giant Leap For Go, or Astronauts Find Life In Space|url= http://homepage.mac.com/bjornwendsjo/go/2-96.pdf|archive-url= https://web.archive.org/web/20120304121705/http://homepage.mac.com/bjornwendsjo/go/2-96.pdf|archive-date=2012-03-04|magazine=Svenks Go Tidning|volume=96|issue=2|year=1996|pages=7–8|access-date=2007-11-12}} | |||
* {{Citation | last = Shotwell | first = Peter | title = Go! More Than a Game | publisher = Tuttle Publishing |edition=1st| year = 2003 | isbn = 978-0-8048-3475-9}} | |||
{{refend}} | |||
== Further reading == | |||
=== Introductory books === | |||
{{refbegin|30em}} | |||
* Bradley, Milton N. ''Go for Kids'', Yutopian Enterprises, Santa Monica, 2001 {{ISBN|978-1-889554-74-7}}. | |||
* {{cite book|ref=none|last1=Ogawa|first1=Tomoko|last2=Davies|first2=James|year=2000|title=The Endgame|series=Elementary Go Series|volume=6|publisher=Kiseido Publishing Company|location=Tokyo|edition=2nd|isbn=4-906574-15-7}} | |||
* Seckiner, Sancar. ''Chinese Go Players'', 6th article of the main book ''Budaha'', Efil Yayinevi, Ankara, Feb. 2016, {{ISBN|978-605-4160-62-4}}. | |||
* Shotwell, Peter. ''Go! More than a Game'', ], 4th ed. 2014, {{ISBN|978-0-8048-3475-9}}. | |||
{{refend}} | |||
=== Historical interest === | |||
{{refbegin|30em}} | |||
* {{Citation|ref=none|last=De Havilland|first=Walter Augustus|author-link=Walter Augustus de Havilland|title=The ABC of Go: The National War Game of Japan|year=1910|publisher=Yokohama, ]|oclc= 4800147}} | |||
* {{Citation|ref=none|last=Korschelt|first=Oscar|author-link=Oskar Korschelt|title=The Theory and Practice of Go|year=1966|publisher=C.E. Tuttle Co|isbn=978-0-8048-0572-8|url= https://archive.org/details/theorypracticeof0000kors}} | |||
* {{Citation|ref=none|last=Smith|first=Arthur|title=The Game of Go: The National Game of Japan|year=1956|orig-year=1908|publisher=C.E. Tuttle Co|oclc= 912228}} | |||
{{refend}} | |||
{{sister bar|auto=1|d=y|wikt=go|s=1911_Encyclopædia_Britannica/Go}} | |||
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Latest revision as of 18:12, 28 November 2024
Abstract strategy board game for two players This article is about the board game. For other uses, see Go (disambiguation).Go is played on a grid (usually 19×19). Game pieces (stones) are placed on the grid line intersections. | |
Years active | 548 BCE (earliest record) to present |
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Genres | |
Players | 2 |
Setup time | Minimal |
Playing time |
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Chance | None |
Skills | Strategy, tactics, elementary arithmetic |
Synonyms |
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Some professional games exceed 16 hours and are played in sessions spread over two days. |
Go | |||||||||||||||||||||||||||||||||||||||||
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Chinese name | |||||||||||||||||||||||||||||||||||||||||
Traditional Chinese | 圍棋 | ||||||||||||||||||||||||||||||||||||||||
Simplified Chinese | 围棋 | ||||||||||||||||||||||||||||||||||||||||
Literal meaning | 'encirclement board game' | ||||||||||||||||||||||||||||||||||||||||
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Tibetan name | |||||||||||||||||||||||||||||||||||||||||
Tibetan | མིག་མངས | ||||||||||||||||||||||||||||||||||||||||
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Vietnamese name | |||||||||||||||||||||||||||||||||||||||||
Vietnamese alphabet | cờ vây | ||||||||||||||||||||||||||||||||||||||||
Hán-Nôm | 碁圍 | ||||||||||||||||||||||||||||||||||||||||
Korean name | |||||||||||||||||||||||||||||||||||||||||
Hangul | 바둑 | ||||||||||||||||||||||||||||||||||||||||
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Japanese name | |||||||||||||||||||||||||||||||||||||||||
Kanji | 囲碁 or 碁 | ||||||||||||||||||||||||||||||||||||||||
Hiragana | いご or ご | ||||||||||||||||||||||||||||||||||||||||
Katakana | イゴ or ゴ | ||||||||||||||||||||||||||||||||||||||||
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Go is an abstract strategy board game for two players in which the aim is to fence off more territory than the opponent. The game was invented in China more than 2,500 years ago and is believed to be the oldest board game continuously played to the present day. A 2016 survey by the International Go Federation's 75 member nations found that there are over 46 million people worldwide who know how to play Go, and over 20 million current players, the majority of whom live in East Asia.
The playing pieces are called stones. One player uses the white stones and the other black. The players take turns placing their stones on the vacant intersections (points) on the board. Once placed, stones may not be moved, but captured stones are immediately removed from the board. A single stone (or connected group of stones) is captured when surrounded by the opponent's stones on all orthogonally adjacent points. The game proceeds until neither player wishes to make another move.
When a game concludes, the winner is determined by counting each player's surrounded territory along with captured stones and komi (points added to the score of the player with the white stones as compensation for playing second). Games may also end by resignation.
The standard Go board has a 19×19 grid of lines, containing 361 points. Beginners often play on smaller 9×9 or 13×13 boards, and archaeological evidence shows that the game was played in earlier centuries on a board with a 17×17 grid. Boards with a 19×19 grid had become standard, however, by the time the game reached Korea in the 5th century CE and Japan in the 7th century CE.
Go was considered one of the four essential arts of the cultured aristocratic Chinese scholars in antiquity. The earliest written reference to the game is generally recognized as the historical annal Zuo Zhuan (c. 4th century BCE).
Despite its relatively simple rules, Go is extremely complex. Compared to chess, Go has both a larger board with more scope for play and longer games and, on average, many more alternatives to consider per move. The number of legal board positions in Go has been calculated to be approximately 2.1×10, which is far greater than the number of atoms in the observable universe, which is estimated to be on the order of 10.
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Names of the game
The name Go is a short form of the Japanese word igo (囲碁; いご), which derives from earlier wigo (ゐご), in turn from Middle Chinese ɦʉi gi (圍棋, Mandarin: wéiqí, lit. 'encirclement board game' or 'board game of surrounding'). In English, the name Go when used for the game is often capitalized to differentiate it from the common word go. In events sponsored by the Ing Chang-ki Foundation, it is spelled goe.
The Korean name baduk (바둑) derives from the Middle Korean word Badok, the origin of which is controversial; the more plausible etymologies include the suffix dok added to Ba to mean 'flat and wide board', or the joining of Bat, meaning 'field', and Dok, meaning 'stone'. Less plausible etymologies include a derivation of Badukdok, referring to the playing pieces of the game, or a derivation from Chinese páizi (排子), meaning 'to arrange pieces'.
Overview
Go is an adversarial game between two players with the objective of capturing territory. That is, occupying and surrounding a larger total empty area of the board with one's stones than the opponent. As the game progresses, the players place stones on the board creating stone "formations" and enclosing spaces. Stones are never moved on the board, but when "captured" are removed from the board. Stones are linked together into a formation by being adjacent along the black lines, not on diagonals (of which there are none). Contests between opposing formations are often extremely complex and may result in the expansion, reduction, or wholesale capture and loss of formations and their enclosed empty spaces (called "eyes"). Another essential component of the game is control of the sente (that is, controlling the offense, so that one's opponent is forced into defensive moves); this usually changes several times during play.
Initially the board is bare, and players alternate turns to place one stone per turn. As the game proceeds, players try to link their stones together into "living" formations (meaning that they are permanently safe from capture), as well as threaten to capture their opponent's stones and formations. Stones have both offensive and defensive characteristics, depending on the situation.
An essential concept is that a formation of stones must have, or be capable of making, at least two enclosed open points known as eyes to preserve itself from being captured. A formation having at least two eyes cannot be captured, even after it is surrounded by the opponent on the outside, because each eye constitutes a liberty that must be filled by the opponent as the final step in capture. A formation having two or more eyes is said to be unconditionally alive, so it can evade capture indefinitely, and a group that cannot form two eyes is said to be dead and can be captured.
The general strategy is to place stones to fence-off territory, attack the opponent's weak groups (trying to kill them so they will be removed), and always stay mindful of the life status of one's own groups. The liberties of groups are countable. Situations where mutually opposing groups must capture each other or die are called capturing races, or semeai. In a capturing race, the group with more liberties will ultimately be able to capture the opponent's stones. Capturing races and the elements of life or death are the primary challenges of Go.
In the end game players may pass rather than place a stone if they think there are no further opportunities for profitable play. The game ends when both players pass or when one player resigns. In general, to score the game, each player counts the number of unoccupied points surrounded by their stones and then subtracts the number of stones that were captured by the opponent. The player with the greater score (after adjusting for handicapping called komi) wins the game.
In the opening stages of the game, players typically establish groups of stones (or bases) near the corners and around the sides of the board, usually starting on the third or fourth line in from the board edge rather than at the very edge of the board. The edges and corners make it easier to develop groups which have better options for life (self-viability for a group of stones that prevents capture) and establish formations for potential territory. Players usually start near the corners because establishing territory is easier with the aid of two edges of the board. Established corner opening sequences are called joseki and are often studied independently. However, in the mid-game, stone groups must also reach in towards the large central area of the board to capture more territory.
Dame are points that lie in between the boundary walls of black and white, and as such are considered to be of no value to either side. Seki are mutually alive pairs of white and black groups where neither has two eyes.
Ko (Chinese and Japanese: 劫) is a potentially indefinitely repeated stone-capture position. The rules do not allow a board position to be repeated. Therefore, any move which would restore the previous board position would not be allowed, and the next player would be forced to play somewhere else. If the play requires a strategic response by the first player, further changing the board, then the second player could "retake the ko," and the first player would be in the same situation of needing to change the board before trying to take the ko back. And so on. Some of these ko fights may be important and decide the life of a large group, while others may be worth just one or two points. Some ko fights are referred to as picnic kos when only one side has a lot to lose. In Japanese, it is called a hanami ko.
Playing with others usually requires a knowledge of each player's strength, indicated by the player's rank (increasing from 30 kyu to 1 kyu, then 1 dan to 7 dan, then 1 dan pro to 9 dan pro). A difference in rank may be compensated by a handicap—Black is allowed to place two or more stones on the board to compensate for White's greater strength. There are different rulesets (Korean, Japanese, Chinese, AGA, etc.), which are almost entirely equivalent, except for certain special-case positions and the method of scoring at the end.
Basic concepts
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Basic strategic aspects include the following:
- Connection: Keeping one's own stones connected means that fewer groups need to make living shape, and one has fewer groups to defend.
- Cut: Keeping opposing stones disconnected means that the opponent needs to defend and make living shape for more groups.
- Stay alive: The simplest way to stay alive is to establish a foothold in the corner or along one of the sides. At a minimum, a group must have two eyes (separate open points) to be alive. An opponent cannot fill in either eye, as any such move is suicidal and prohibited in the rules.
- Mutual life (seki) is better than dying: A situation in which neither player can play on a particular point without then allowing the other player to play at another point to capture. The most common example is that of adjacent groups that share their last few liberties—if either player plays in the shared liberties, they can reduce their own group to a single liberty (putting themselves in atari), allowing their opponent to capture it on the next move.
- Death: A group that lacks living shape is eventually removed from the board as captured.
- Invasion: Set up a new living group inside an area where the opponent has greater influence, means one reduces the opponent's score in proportion to the area one occupies.
- Reduction: Placing a stone far enough into the opponent's area of influence to reduce the amount of territory they eventually get, but not so far that it can be cut off from friendly stones outside.
- Sente: A play that forces one's opponent to respond (gote). A player who can regularly play sente has the initiative and can control the flow of the game.
- Sacrifice: Allowing a group to die in order to carry out a play, or plan, in a more important area.
The strategy involved can become very abstract and complex. High-level players spend years improving their understanding of strategy, and a novice may play many hundreds of games against opponents before being able to win regularly.
Strategy
Main article: Go strategy and tacticsStrategy deals with global influence, the interaction between distant stones, keeping the whole board in mind during local fights, and other issues that involve the overall game. It is therefore possible to allow a tactical loss when it confers a strategic advantage.
Novices often start by randomly placing stones on the board, as if it were a game of chance. An understanding of how stones connect for greater power develops, and then a few basic common opening sequences may be understood. Learning the ways of life and death helps in a fundamental way to develop one's strategic understanding of weak groups. A player who both plays aggressively and can handle adversity is said to display kiai, or fighting spirit, in the game.
Opening strategy
Main article: Go openingIn the opening of the game, players usually play and gain territory in the corners of the board first, as the presence of two edges makes it easier for them to surround territory and establish the eyes they need. From a secure position in a corner, it is possible to lay claim to more territory by extending along the side of the board. The opening is the most theoretically difficult part of the game and takes a large proportion of professional players' thinking time. The first stone played at a corner of the board is generally placed on the third or fourth line from the edge. Players tend to play on or near the 4–4 star point during the opening. Playing nearer to the edge does not produce enough territory to be efficient, and playing further from the edge does not safely secure the territory.
In the opening, players often play established sequences called joseki, which are locally balanced exchanges; however, the joseki chosen should also produce a satisfactory result on a global scale. It is generally advisable to keep a balance between territory and influence. Which of these gets precedence is often a matter of individual taste.
Middlegame and endgame
The middle phase of the game is the most combative, and usually lasts for more than 100 moves. During the middlegame, the players invade each other's territories, and attack formations that lack the necessary two eyes for viability. Such groups may be saved or sacrificed for something more significant on the board. It is possible that one player may succeed in capturing a large weak group of the opponent's, which often proves decisive and ends the game by a resignation. However, matters may be more complex yet, with major trade-offs, apparently dead groups reviving, and skillful play to attack in such a way as to construct territories rather than kill.
The end of the middlegame and transition to the endgame is marked by a few features. Near the end of a game, play becomes divided into localized fights that do not affect each other, with the exception of ko fights, where before the central area of the board related to all parts of it. No large weak groups are still in serious danger. Moves can reasonably be attributed some definite value, such as 20 points or fewer, rather than simply being necessary to compete. Both players set limited objectives in their plans, in making or destroying territory, capturing or saving stones. These changing aspects of the game usually occur at much the same time, for strong players. In brief, the middlegame switches into the endgame when the concepts of strategy and influence need reassessment in terms of concrete final results on the board.
Rules
Main article: Rules of GoAside from the order of play (alternating moves, Black moves first or takes a handicap) and scoring rules, there are essentially only two rules in Go:
- Liberty rule states that every stone remaining on the board must have at least one open point (a liberty) directly orthogonally adjacent (up, down, left, or right), or must be part of a connected group that has at least one such open point (liberty) next to it. Stones or groups of stones which lose their last liberty are removed from the board.
- Repetition Rule (the ko rule) states that a stone on the board must never immediately repeat a previous position of a captured stone, thus only a move elsewhere on the board is permitted that turn. Since without this rule such a pattern of the two players repeating their prior moves (capturing stones in same places) could continue indefinitely, this rule prevents a stalemate.
Almost all other information about how the game is played is heuristic, meaning it is learned information about how the patterns of the stones on the board function, rather than a rule. Other rules are specialized, as they come about through different rulesets, but the above two rules cover almost all of any played game.
Although there are some minor differences between rulesets used in different countries, most notably in Chinese and Japanese scoring rules, these differences do not greatly affect the tactics and strategy of the game.
Except where noted, the basic rules presented here are valid independent of the scoring rules used. The scoring rules are explained separately. Go terms for which there is no ready English equivalent are commonly called by their Japanese names.
Basic rules
The two players, Black and White, take turns placing stones of their color on the intersections of the board, one stone at a time. The usual board size is a 19×19 grid, but for beginners or for playing quick games, the smaller board sizes of 13×13 and 9×9 are also popular. The board is empty to begin with. Black plays first unless given a handicap of two or more stones, in which case White plays first. The players may choose any unoccupied intersection to play on except for those forbidden by the ko and suicide rules (see below). Once played, a stone can never be moved and can be taken off the board only if it is captured. A player may pass their turn, declining to place a stone, though this is usually only done at the end of the game when both players believe nothing more can be accomplished with further play. When both players pass consecutively, the game ends and is then scored.
Liberties and capture
Vertically and horizontally adjacent stones of the same color form a chain (also called a string or group), forming a discrete unit that cannot then be divided. Only stones connected to one another by the lines on the board create a chain; stones that are diagonally adjacent are not connected. Chains may be expanded by placing additional stones on adjacent intersections, and they can be connected together by placing a stone on an intersection that is adjacent to two or more chains of the same color.
A vacant point adjacent to a stone, along one of the grid lines of the board, is called a liberty for that stone. Stones in a chain share their liberties. A chain of stones must have at least one liberty to remain on the board. When a chain is surrounded by opposing stones so that it has no liberties, it is captured and removed from the board.
Ko rule
Main article: Ko fightAn example of a situation in which the ko rule applies
Players are not allowed to make a move that returns the game to the immediately prior position. This rule, called the ko rule, prevents unending repetition (a stalemate). As shown in the example pictured: White had a stone where the red circle was, and Black has just captured it by playing a stone at 1 (so the White stone has been removed). However, it is readily apparent that now Black's stone at 1 is immediately threatened by the three surrounding White stones. If White were allowed to play again on the red circle, it would return the situation to the original one, but the ko rule forbids that kind of endless repetition. Thus, White is forced to move elsewhere, or pass. If White wants to recapture Black's stone at 1, White must attack Black somewhere else on the board so forcefully that Black moves elsewhere to counter that, giving White that chance. If White's forcing move is successful, it is termed "gaining the sente"; if Black responds elsewhere on the board, then White can retake Black's stone at 1, and the ko continues, but this time Black must move elsewhere. A repetition of such exchanges is called a ko fight. To stop the potential for ko fights, two stones of the same color would need to be added to the group, making either a group of 5 Black or 5 White stones.
While the various rulesets agree on the ko rule prohibiting returning the board to an immediately previous position, they deal in different ways with the relatively uncommon situation in which a player might recreate a past position that is further removed. See Rules of Go § Repetition for further information.
Suicide
A player may not place a stone such that it or its group immediately has no liberties unless doing so immediately deprives an enemy group of its final liberty. In the second case, the enemy group is captured, leaving the new stone with at least one liberty, so the new stone can be placed. This rule is responsible for the all-important difference between one and two eyes: if a group with only one eye is fully surrounded on the outside, it can be killed with a stone placed in its single eye. (An eye is an empty point or group of points surrounded by a group of stones).
The Ing and New Zealand rules do not have this rule, and there a player might destroy one of its own groups (commit suicide). This play would only be useful in limited sets of situations involving a small interior space or planning. In the example at right, it may be useful as a ko threat.
Komi
Main article: Komi (Go)Because Black has the advantage of playing the first move, the idea of awarding White some compensation came into being during the 20th century. This is called komi, which gives white a 5.5-point compensation under Japanese rules, 6.5-point under Korean rules, and 15/4 stones, or 7.5-point under Chinese rules (number of points varies by rule set). Under handicap play, White receives only a 0.5-point komi, to break a possible tie (jigo).
Scoring rules
Two general types of scoring procedures are used, and players determine which to use before play. Both procedures almost always give the same winner.
- Area scoring procedure (including Chinese): counts the number of points a player's stones occupy and surround. It is associated with contemporary Chinese play and was probably established there during the Ming dynasty in the 15th or 16th century. Beginner-friendly, but takes longer to count. A player's score is the number of stones that the player has on the board, plus the number of empty intersections surrounded by that player's stones. If there is disagreement about which stones are dead, then under area scoring rules, the players simply resume play to resolve the matter. The score is computed using the position after the next time the players pass consecutively.
- Territory scoring procedure (including Japanese and Korean): counts the number of empty points a player's stones surround, together with the number of stones the player captured. In the course of the game, each player retains the stones they capture, termed prisoners. Any dead stones removed at the end of the game become prisoners. The score is the number of empty points enclosed by a player's stones, plus the number of prisoners captured by that player. Under territory scoring there can be an extra penalty for playing inside ones' territory, so if there is a disagreement extra play to resolve it would, in tournament settings, happen on a separate board, where the player claiming a group is dead would play first, and would demonstrate how to capture those stones. For further information, see Rules of Go.
Both procedures are counted after both players have passed consecutively, the stones that are still on the board but unable to avoid capture, called dead stones, are removed. Given that the number of stones a player has on the board is directly related to the number of prisoners their opponent has taken, the resulting net score, that is, the difference between Black's and White's scores is identical under both rulesets (unless the players have passed different numbers of times during the course of the game). Thus, the net result given by the two scoring systems rarely differs by more than a point.
Life and death
See also: Life and deathWhile not actually mentioned in the rules of Go (at least in simpler rule sets, such as those of New Zealand and the U.S.), the concept of a living group of stones is necessary for a practical understanding of the game.
Examples of eyes (marked). The black groups at the top of the board are alive, as they have at least two eyes. The black groups at the bottom are dead as they only have one eye. The point marked a is a false eye, thus the black group with false eye a can be killed by white in two turns.
When a group of stones is mostly surrounded and has no options to connect with friendly stones elsewhere, the status of the group is either alive, dead or unsettled. A group of stones is said to be alive if it cannot be captured, even if the opponent is allowed to move first. Conversely, a group of stones is said to be dead if it cannot avoid capture, even if the owner of the group is allowed the first move. Otherwise, the group is said to be unsettled: the defending player can make it alive or the opponent can kill it, depending on who gets to play first.
An eye is an empty point or group of points surrounded by a group of stones. If the eye is surrounded by Black stones, White cannot play there unless such a play would take Black's last liberty and capture the Black stones. (Such a move is forbidden according to the suicide rule in most rule sets, but even if not forbidden, such a move would be a useless suicide of a White stone.)
If a Black group has two eyes, White can never capture it because White cannot remove both liberties simultaneously. If Black has only one eye, White can capture the Black group by playing in the single eye, removing Black's last liberty. Such a move is not suicide because the Black stones are removed first. In the "Examples of eyes" diagram, all the circled points are eyes. The two black groups in the upper corners are alive, as both have at least two eyes. The groups in the lower corners are dead, as both have only one eye. The group in the lower left may seem to have two eyes, but the surrounded empty point marked a is not actually an eye. White can play there and take a black stone. Such a point is often called a false eye.
Seki (mutual life)
There is an exception to the requirement that a group must have two eyes to be alive, a situation called seki (or mutual life). Where different colored groups are adjacent and share liberties, the situation may reach a position when neither player wants to move first because doing so would allow the opponent to capture; in such situations therefore both players' stones remain on the board (in seki). Neither player receives any points for those groups, but at least those groups themselves remain living, as opposed to being captured.
Seki can occur in many ways. The simplest are:
- each player has a group without eyes and they share two liberties, and
- each player has a group with one eye and they share one more liberty.
In the "Example of seki (mutual life)" diagram, the two circled points are liberties shared by both a black and a white group. Both of these interior groups are at risk, and neither player wants to play on a circled point, because doing so would allow the opponent to capture their group on the next move. The outer groups in this example, both black and white, are alive. Seki can result from an attempt by one player to invade and kill a nearly settled group of the other player.
Tactics
Main article: Go strategy and tacticsTactics deal with immediate fighting between stones, capturing and saving stones, life, death and other issues localized to a specific part of the board. Larger issues which encompass the territory of the entire board and planning stone-group connections are referred to as Strategy and are covered in the Strategy section above.
Capturing tactics
There are several tactical constructs aimed at capturing stones. These are among the first things a player learns after understanding the rules. Recognizing the possibility that stones can be captured using these techniques is an important step forward.
A ladder. Black cannot escape unless the ladder connects to black stones further down the board that will intercept with the ladder or if one of white's pieces has only one liberty.
The most basic technique is the ladder. This is also sometimes called a "running attack", since it unfolds as one player trying to outrun the other's attack. To capture stones in a ladder, a player uses a constant series of capture threats (atari), giving the opponent only one place to place his stone to keep his group alive. This forces the opponent to move into a zigzag pattern (surrounding the ladder on the outside) as shown in the adjacent diagram to keep the attack coming. Unless the pattern runs into friendly stones along the way, the stones in the ladder cannot avoid capture. However, if the ladder can run into other black stones, thus saving them, then experienced players recognize the futility of continuing the attack. These stones can also be saved if a suitably strong threat can be forced elsewhere on the board, so that two Black stones can be placed here to save the group.
A net. The chain of three marked Black stones cannot escape in any direction, since each Black stone attempting to extend the chain outward (on the red circles) can be easily blocked by one White stone.
Another technique to capture stones is the so-called net, also known by its Japanese name, geta. This refers to a move that loosely surrounds some stones, preventing their escape in all directions. An example is given in the adjacent diagram. It is often better to capture stones in a net than in a ladder, because a net does not depend on the condition that there are no opposing stones in the way, nor does it allow the opponent to play a strategic ladder breaker. However, the ladder only requires one turn to kill all the opponent's stones, whereas a net requires more turns to do the same.
A snapback. Although Black can capture the white stone by playing at the circled point, the resulting shape for Black has only one liberty (at 1), thus White can then capture the three black stones by playing at 1 again (snapback).
A third technique to capture stones is the snapback. In a snapback, one player allows a single stone to be captured, then immediately plays on the point formerly occupied by that stone; by so doing, the player captures a larger group of their opponent's stones, in effect snapping back at those stones. An example can be seen on the right. As with the ladder, an experienced player does not play out such a sequence, recognizing the futility of capturing only to be captured back immediately.
Reading ahead
One of the most important skills required for strong tactical play is the ability to read ahead. Reading ahead includes considering available moves to play, the possible responses to each move, and the subsequent possibilities after each of those responses. Some of the strongest players of the game can read up to 40 moves ahead even in complicated positions.
As explained in the scoring rules, some stone formations can never be captured and are said to be alive, while other stones may be in a position where they cannot avoid being captured and are said to be dead. Much of the practice material available to players of the game comes in the form of life and death problems, also known as tsumego. In such problems, players are challenged to find the vital move sequence that kills a group of the opponent or saves a group of their own. Tsumego are considered an excellent way to train a player's ability at reading ahead, and are available for all skill levels, some posing a challenge even to top players.
Ko fighting
In situations when the Ko rule applies, a ko fight may occur. If the player who is prohibited from capture is of the opinion that the capture is important because it prevents a large group of stones from being captured for instance, the player may play a ko threat. This is a move elsewhere on the board that threatens to make a large profit if the opponent does not respond. If the opponent does respond to the ko threat, the situation on the board has changed, and the prohibition on capturing the ko no longer applies. Thus the player who made the ko threat may now recapture the ko. Their opponent is then in the same situation and can either play a ko threat as well or concede the ko by simply playing elsewhere. If a player concedes the ko, either because they do not think it important or because there are no moves left that could function as a ko threat, they have lost the ko, and their opponent may connect the ko.
Instead of responding to a ko threat, a player may also choose to ignore the threat and connect the ko. They thereby win the ko, but at a cost. The choice of when to respond to a threat and when to ignore it is a subtle one, which requires a player to consider many factors, including how much is gained by connecting, how much is lost by not responding, how many possible ko threats both players have remaining, what the optimal order of playing them is, and what the size—points lost or gained—of each of the remaining threats is.
Frequently, the winner of the ko fight does not connect the ko but instead captures one of the chains that constituted their opponent's side of the ko. In some cases, this leads to another ko fight at a neighboring location.
History
Main article: History of GoOrigin in China
The earliest written reference to the game is generally recognized as the historical annal Zuo Zhuan (c. 4th century BCE), referring to a historical event of 548 BCE. It is also mentioned in Book XVII of the Analects of Confucius and in two books written by Mencius (c. 3rd century BCE). In all of these works, the game is referred to as yì (弈). Today, in China, it is known as weiqi (simplified Chinese: 围棋; traditional Chinese: 圍棋; pinyin: wéiqí; Wade–Giles: wei ch'i), lit. 'encirclement board game'.
Go was originally played on a 17×17 line grid, but a 19×19 grid became standard by the time of the Tang dynasty (618–907 CE). Legends trace the origin of the game to the mythical Chinese emperor Yao (2337–2258 BCE), who was said to have had his counselor Shun design it for his unruly son, Danzhu, to favorably influence him. Other theories suggest that the game was derived from Chinese tribal warlords and generals, who used pieces of stone to map out attacking positions.
In China, Go had an important status among elites and was associated with ideas of self-cultivation, wisdom, and gentlemanly ideals. It was considered one of the four cultivated arts of the Chinese scholar gentleman, along with calligraphy, painting and playing the musical instrument guqin. In ancient times the rules of Go were passed on verbally, rather than being written down.
- Model of a 19×19 Go board, from a tomb of the Sui dynasty (581–618 CE)
- Painting of a woman playing Go, from the Astana Graves. Tang dynasty, c. 744 CE.
- Li Jing playing Go with his brothers. Detail from a painting by Zhou Wenju (fl. 942–961 CE), Southern Tang dynasty.
Spread to Korea and Japan
Go was introduced to Korea sometime between the 5th and 7th centuries CE, and was popular among the higher classes. In Korea, the game is called baduk (Korean: 바둑), and a variant of the game called Sunjang baduk was developed by the 16th century. Sunjang baduk became the main variant played in Korea until the end of the 19th century, when the current version was reintroduced from Japan.
The game reached Japan in the 7th century CE—where it is called go (碁) or igo (囲碁). It became popular at the Japanese imperial court in the 8th century, and among the general public by the 13th century. The game was further formalized in the 15th century. In 1603, Tokugawa Ieyasu re-established Japan's unified national government. In the same year, he assigned the then-best player in Japan, a Buddhist monk named Nikkai (né Kanō Yosaburo, 1559), to the post of Godokoro (Minister of Go).
Nikkai took the name Hon'inbō Sansa and founded the Hon'inbō Go school. Several competing schools were founded soon after. These officially recognized and subsidized Go schools greatly developed the level of play and introduced the dan/kyu style system of ranking players. Players from the four schools (Hon'inbō, Yasui, Inoue and Hayashi) competed in the annual castle games, played in the presence of the shōgun.
- Detail from a Japanese illustrated handscroll of The Tale of Genji. Heian period, 12th century CE.
- A Korean couple playing Go in traditional dress. Photographed between 1910 and 1920.
Internationalization
Despite its widespread popularity in East Asia, Go has been slow to spread to the rest of the world. Although there are some mentions of the game in western literature from the 16th century forward, Go did not start to become popular in the West until the end of the 19th century, when German scientist Oskar Korschelt wrote a treatise on the game. By the early 20th century, Go had spread throughout the German and Austro-Hungarian empires. In 1905, Edward Lasker learned the game while in Berlin. When he moved to New York, Lasker founded the New York Go Club together with (amongst others) Arthur Smith, who had learned of the game in Japan while touring the East and had published the book The Game of Go in 1908. Lasker's book Go and Go-moku (1934) helped spread the game throughout the U.S., and in 1935, the American Go Association was formed. Two years later, in 1937, the German Go Association was founded.
World War II put a stop to most Go activity, since it was a popular game in Japan, but after the war, Go continued to spread. For most of the 20th century, the Japan Go Association (Nihon Ki-in) played a leading role in spreading Go outside East Asia by publishing the English-language magazine Go Review in the 1960s, establishing Go centers in the U.S., Europe and South America, and often sending professional teachers on tour to Western nations. Internationally, the game had been commonly known since the start of the twentieth century by its shortened Japanese name, and terms for common Go concepts are derived from their Japanese pronunciation.
In 1996, NASA astronaut Daniel Barry and Japanese astronaut Koichi Wakata became the first people to play Go in space. They used a special Go set, which was named Go Space, designed by Wai-Cheung Willson Chow. Both astronauts were awarded honorary dan ranks by the Nihon Ki-in.
As of December 2015, the International Go Federation has 75 member countries, with 67 member countries outside East Asia. Chinese cultural centres across the world are promoting Go, and cooperating with local Go associations, for example the seminars held by the Chinese cultural centre in Tel Aviv, Israel, together with the Israeli Go association.
Competitive play
Ranks and ratings
Main article: Go ranks and ratingsIn Go, rank indicates a player's skill in the game. Traditionally, ranks are measured using kyu and dan grades, a system also adopted by many martial arts. More recently, mathematical rating systems similar to the Elo rating system have been introduced. Such rating systems often provide a mechanism for converting a rating to a kyu or dan grade. Kyu grades (abbreviated k) are considered student grades and decrease as playing level increases, meaning 1st kyu is the strongest available kyu grade. Dan grades (abbreviated d) are considered master grades, and increase from 1st dan to 7th dan. First dan equals a black belt in eastern martial arts using this system. The difference among each amateur rank is one handicap stone. For example, if a 5k plays a game with a 1k, the 5k would need a handicap of four stones to even the odds. Top-level amateur players sometimes defeat professionals in tournament play. Professional players have professional dan ranks (abbreviated p). These ranks are separate from amateur ranks.
The rank system comprises, from the lowest to highest ranks:
Rank Type | Range | Stage |
---|---|---|
Double-digit kyu | 30–21k | Beginner |
Double-digit kyu | 20–10k | Casual player |
Single-digit kyu | 9–1k | Intermediate/club player |
Amateur dan | 1–7d (where 8d is a special title) | Advanced player |
Professional dan | 1–9p (where 10p is a special title) | Professionals |
Tournament and match rules
See also: Go competitionsTournament and match rules deal with factors that may influence the game but are not part of the actual rules of play. Such rules may differ between events. Rules that influence the game include: the setting of compensation points (komi), handicap, and time control parameters. Rules that do not generally influence the game are the tournament system, pairing strategies, and placement criteria.
Common tournament systems used in Go include the McMahon system, Swiss system, league systems and the knockout system. Tournaments may combine multiple systems; many professional Go tournaments use a combination of the league and knockout systems.
Tournament rules may also set the following:
- compensation points, called komi, which compensate the second player for the first move advantage of their opponent; tournaments commonly use a compensation in the range of 5–8 points, generally including a half-point to prevent draws;
- handicap stones placed on the board before alternate play, allowing players of different strengths to play competitively (see Go handicap for more information); and
- superko: Although the basic ko rule described above covers more than 95% of all cycles occurring in games, there are some complex situations—triple ko, eternal life, etc.—that are not covered by it but would allow the game to cycle indefinitely. To prevent this, the ko rule is sometimes extended to forbid the repetition of any previous position. This extension is called superko.
Time control
See also: Time control and ByoyomiA game of Go may be timed using a game clock. Formal time controls were introduced into the professional game during the 1920s and were controversial. Adjournments and sealed moves began to be regulated in the 1930s. Go tournaments use a number of different time control systems. All common systems envisage a single main period of time for each player for the game, but they vary on the protocols for continuation (in overtime) after a player has finished that time allowance. The most widely used time control system is the so-called byoyomi system. The top professional Go matches have timekeepers so that the players do not have to press their own clocks.
Two widely used variants of the byoyomi system are:
- Standard byoyomi: After the main time is depleted, a player has a certain number of time periods (typically around thirty seconds). After each move, the number of full-time periods that the player took (often zero) is subtracted. For example, if a player has three thirty-second time periods and takes thirty or more (but less than sixty) seconds to make a move, they lose one time period. With 60–89 seconds, they lose two time periods, and so on. If, however, they take less than thirty seconds, the timer simply resets without subtracting any periods. Using up the last period means that the player has lost on time.
- Canadian byoyomi: After using all of their main time, a player must make a certain number of moves within a certain period of time, such as twenty moves within five minutes. If the time period expires without the required number of stones having been played, then the player has lost on time.
Notation and recording games
Main article: Go game recordGo games are recorded with a simple coordinate system. This is comparable to algebraic chess notation, except that Go stones do not move and thus require only one coordinate per turn. Coordinate systems include purely numerical (4–4 point), hybrid (K3), and purely alphabetical. The Smart Game Format uses alphabetical coordinates internally, but most editors represent the board with hybrid coordinates as this reduces confusion.
Alternatively, the game record can also be noted by writing the successive moves on a diagram, where odd numbers mean black stones, even numbers mean white stones (or conversely when playing with a handicap), and a notation like "25=22" in the margin means that the 25th stone was played at the same location as the 22nd one, which had been captured in the meantime.
The Japanese word kifu is sometimes used to refer to a game record.
In Unicode, Go stones can be represented with black and white circles from the block Geometric Shapes:
- U+25CB ○ WHITE CIRCLE (○)
- U+25CF ● BLACK CIRCLE
The block Miscellaneous Symbols includes "Go markers" that were likely meant for mathematical research of Go:
- U+2686 ⚆ WHITE CIRCLE WITH DOT RIGHT
- U+2687 ⚇ WHITE CIRCLE WITH TWO DOTS
- U+2688 ⚈ BLACK CIRCLE WITH WHITE DOT RIGHT
- U+2689 ⚉ BLACK CIRCLE WITH TWO WHITE DOTS
Top players and professional Go
See also: List of top title holders in Go, Go players, Female Go players, Go professional, and List of professional Go tournamentsA Go professional is a professional player of the game of Go. There are six areas with professional go associations, these are: China (Chinese Weiqi Association), Japan (Nihon Ki-in, Kansai Ki-in), South Korea (Korea Baduk Association), Taiwan (Taiwan Chi Yuan Culture Foundation), the United States (AGA Professional System) and Europe (European Professional System).
Although the game was developed in China, the establishment of the Four Go houses by Tokugawa Ieyasu at the start of the 17th century shifted the focus of the Go world to Japan. State sponsorship, allowing players to dedicate themselves full-time to study of the game, and fierce competition between individual houses resulted in a significant increase in the level of play. During this period, the best player of his generation was given the prestigious title Meijin (master) and the post of Godokoro (minister of Go). Of special note are the players who were dubbed Kisei (Go Sage). The only three players to receive this honor were Dōsaku, Jōwa and Shūsaku, all of the house Hon'inbō.
After the end of the Tokugawa shogunate and the Meiji Restoration period, the Go houses slowly disappeared, and in 1924, the Nihon Ki-in (Japanese Go Association) was formed. Top players from this period often played newspaper-sponsored matches of 2–10 games. Of special note are the (Chinese-born) player Go Seigen (Chinese: Wu Qingyuan), who scored 80% in these matches and beat down most of his opponents to inferior handicaps, and Minoru Kitani, who dominated matches in the early 1930s. These two players are also recognized for their groundbreaking work on new opening theory (Shinfuseki).
For much of the 20th century, Go continued to be dominated by players trained in Japan. Notable names included Eio Sakata, Rin Kaiho (born in Taiwan), Masao Kato, Koichi Kobayashi and Cho Chikun (born Cho Ch'i-hun, from South Korea). Top Chinese and Korean talents often moved to Japan, because the level of play there was high and funding was more lavish. One of the first Korean players to do so was Cho Namchul, who studied in the Kitani Dojo 1937–1944. After his return to Korea, the Hanguk Kiwon (Korea Baduk Association) was formed and caused the level of play in South Korea to rise significantly in the second half of the 20th century. In China, the game declined during the Cultural Revolution (1966–1976) but quickly recovered in the last quarter of the 20th century, bringing Chinese players, such as Nie Weiping and Ma Xiaochun, on par with their Japanese and South Korean counterparts. The Chinese Weiqi Association (today part of the China Qiyuan) was established in 1962, and professional dan grades started being issued in 1982. Western professional Go began in 2012 with the American Go Association's Professional System. In 2014, the European Go Federation followed suit and started their professional system.
With the advent of major international titles from 1989 onward, it became possible to compare the level of players from different countries more accurately. Cho Hunhyun of South Korea won the first edition of the Quadrennial Ing Cup in 1989. His disciple Lee Chang-ho was the dominant player in international Go competitions for more than a decade spanning much of 1990s and early 2000s; he is also credited with groundbreaking works on the endgame. Cho, Lee and other South Korean players such as Seo Bong-soo, Yoo Changhyuk and Lee Sedol between them won the majority of international titles in this period. Several Chinese players also rose to the top in international Go from 2000s, most notably Ma Xiaochun, Chang Hao, Gu Li and Ke Jie. As of 2016, Japan lags behind in the international Go scene.
Historically, more men than women have played Go. Special tournaments for women exist, but until recently, men and women did not compete together at the highest levels; however, the creation of new, open tournaments and the rise of strong female players, most notably Rui Naiwei, have in recent years highlighted the strength and competitiveness of emerging female players.
The level in other countries has traditionally been much lower, except for some players who had preparatory professional training in East Asia. Knowledge of the game has been scant elsewhere up until the 20th century. A famous player of the 1920s was Edward Lasker. It was not until the 1950s that more than a few Western players took up the game as other than a passing interest. In 1978, Manfred Wimmer became the first Westerner to receive a professional player's certificate from an East Asian professional Go association. In 2000, American Michael Redmond became the first Western player to achieve a 9 dan rank.
Equipment
Main article: Go equipmentIt is possible to play Go with a simple paper board and coins, plastic tokens, or white beans and coffee beans for the stones; or even by drawing the stones on the board and erasing them when captured. More popular midrange equipment includes cardstock, a laminated particle board, or wood boards with stones of plastic or glass. More expensive traditional materials are still used by many players. The most expensive Go sets have black stones carved from slate and white stones carved from translucent white shells (traditionally Meretrix lamarckii), played on boards carved in a single piece from the trunk of a tree.
Traditional equipment
Boards
The Go board (generally referred to by its Japanese name goban 碁盤) typically measures between 45 and 48 cm (18 and 19 in) in length (from one player's side to the other) and 42 to 44 cm (16+1⁄2 to 17+1⁄4 in) in width. Chinese boards are slightly larger, as a traditional Chinese Go stone is slightly larger to match. The board is not square; there is a 15:14 ratio in length to width, because with a perfectly square board, from the player's viewing angle the perspective creates a foreshortening of the board. The added length compensates for this. There are two main types of boards: a table board similar in most respects to other gameboards like that used for chess, and a floor board, which is its own free-standing table and at which the players sit.
The traditional Japanese goban is between 10 and 18 cm (3.9 and 7.1 in) thick and has legs; it sits on the floor (see picture). It is preferably made from the rare golden-tinged Kaya tree (Torreya nucifera), with the very best made from Kaya trees up to 700 years old. More recently, the related California Torreya (Torreya californica) has been prized for its light color and pale rings as well as its reduced expense and more readily available stock. The natural resources of Japan have been unable to keep up with the enormous demand for the slow-growing Kaya trees; both T. nucifera and T. californica take many hundreds of years to grow to the necessary size, and they are now extremely rare, raising the price of such equipment tremendously. As Kaya trees are a protected species in Japan, they cannot be harvested until they have died. Thus, an old-growth, floor-standing Kaya goban can easily cost in excess of $10,000 with the highest-quality examples costing more than $60,000.
Other, less expensive woods often used to make quality table boards in both Chinese and Japanese dimensions include Hiba (Thujopsis dolabrata), Katsura (Cercidiphyllum japonicum), Kauri (Agathis), and Shin Kaya (various varieties of spruce, commonly from Alaska, Siberia and China's Yunnan Province). So-called Shin Kaya is a potentially confusing merchant's term: shin means 'new', and thus shin kaya is best translated 'faux kaya', because the woods so described are biologically unrelated to Kaya.
Stones
A full set of Go stones (goishi) usually contains 181 black stones and 180 white ones; a 19×19 grid has 361 points, so there are enough stones to cover the board, and Black gets the extra odd stone because that player goes first. However it may happen, especially in beginners' games, that many back-and-forth captures empty the bowls before the end of the game: in that case an exchange of prisoners allows the game to continue.
Traditional Japanese stones are double-convex, and made of clamshell (white) and slate (black). The classic slate is nachiguro stone mined in Wakayama Prefecture and the clamshell from the Hamaguri clam (Meretrix lusoria) or the Korean hard clam; however, due to a scarcity in the Japanese supply of these clams, the stones are most often made of shells harvested from Mexico. Historically, the most prized stones were made of jade, often given to the reigning emperor as a gift.
In China, the game is traditionally played with single-convex stones made of a composite called Yunzi. The material comes from Yunnan Province and is made by sintering a proprietary and trade-secret mixture of mineral compounds derived from the local stone. This process dates to the Tang dynasty and, after the knowledge was lost in the 1920s during the Chinese Civil War, was rediscovered in the 1960s by the now state-run Yunzi company. The material is praised for its colors, its pleasing sound as compared to glass or to synthetics such as melamine, and its lower cost as opposed to other materials such as slate/shell. The term yunzi can also refer to a single-convex stone made of any material; however, most English-language Go suppliers specify Yunzi as a material and single-convex as a shape to avoid confusion, as stones made of Yunzi are also available in double-convex while synthetic stones can be either shape.
Traditional stones are made so that black stones are slightly larger in diameter than white; this is to compensate for the optical illusion created by contrasting colors that would make equal-sized white stones appear larger on the board than black stones.
Bowls
The bowls for the stones are shaped like a flattened sphere with a level underside. The lid is loose fitting and upturned before play to receive stones captured during the game. Chinese bowls are slightly larger, and a little more rounded, a style known generally as Go Seigen; Japanese Kitani bowls tend to have a shape closer to that of the bowl of a snifter glass, such as for brandy. The bowls are usually made of turned wood. Mulberry is the traditional material for Japanese bowls, but is very expensive; wood from the Chinese jujube date tree, which has a lighter color (it is often stained) and slightly more visible grain pattern, is a common substitute for rosewood, and traditional for Go Seigen-style bowls. Other traditional materials used for making Chinese bowls include lacquered wood, ceramics, stone and woven straw or rattan. The names of the bowl shapes, Go Seigen and Kitani, were introduced in the last quarter of the 20th century by the professional player Janice Kim as homage to two 20th-century professional Go players by the same names, of Chinese and Japanese nationality, respectively, who are referred to as the "Fathers of modern Go".
Playing technique and etiquette
The traditional way to place a Go stone is to first take one from the bowl, gripping it between the index and middle fingers, with the middle finger on top, and then placing it directly on the desired intersection. One can also place a stone on the board and then slide it into position under appropriate circumstances (where it does not move any other stones). It is considered respectful towards White for Black to place the first stone of the game in the upper right-hand corner. (Because of symmetry, this has no effect on the game's outcome.)
It is considered poor manners to run one's fingers through one's bowl of unplayed stones, as the sound, however soothing to the player doing this, can be disturbing to one's opponent. Similarly, clacking a stone against another stone, the board, or the table or floor is also discouraged. However, it is permissible to emphasize select moves by striking the board more firmly than normal, thus producing a sharp clack. Additionally, hovering one's arm over the board (usually when deciding where to play) is also considered rude as it obstructs the opponent's view of the board.
Manners and etiquette are extensively discussed in 'The Classic of WeiQi in Thirteen Chapters', a Song dynasty manual to the game. Apart from the points above it also points to the need to remain calm and honorable, in maintaining posture, and knowing the key specialised terms, such as titles of common formations. Generally speaking, much attention is paid to the etiquette of playing, as much as to winning or actual game technique.
Computers and Go
Main article: Computer GoSoftware players
Go long posed a daunting challenge to computer programmers, putting forward "difficult decision-making tasks, an intractable search space, and an optimal solution so complex it appears infeasible to directly approximate using a policy or value function". Prior to 2015, the best Go programs only managed to reach amateur dan level. On smaller 9×9 and 13x13 boards, computer programs fared better, and were able to compare to professional players. Many in the field of artificial intelligence consider Go to require more elements that mimic human thought than chess.
The reasons why computer programs had not played Go at the professional dan level prior to 2016 include:
- The number of spaces on the board is much larger (over five times the number of spaces on a chess board—361 vs. 64). On most turns there are many more possible moves in Go than in chess. Throughout most of the game, the number of legal moves stays at around 150–250 per turn, and rarely falls below 100 (in chess, the average number of moves is 37). Because an exhaustive computer program for Go must calculate and compare every possible legal move in each ply (player turn), its ability to calculate the best plays is sharply reduced when there are a large number of possible moves. Most computer game algorithms, such as those for chess, compute several moves in advance. Given an average of 200 available moves through most of the game, for a computer to calculate its next move by exhaustively anticipating the next four moves of each possible play (two of its own and two of its opponent's), it would have to consider more than 320 billion (3.2×10) possible combinations. To exhaustively calculate the next eight moves, would require computing 512 quintillion (5.12×10) possible combinations. As of March 2014, the most powerful supercomputer in the world, NUDT's "Tianhe-2", can sustain 33.86 petaflops. At this rate, even given an exceedingly low estimate of 10 operations required to assess the value of one play of a stone, Tianhe-2 would require four hours to assess all possible combinations of the next eight moves in order to make a single play.
- The placement of a single stone in the initial phase can affect the play of the game a hundred or more moves later. A computer would have to predict this influence, and it would be unworkable to attempt to exhaustively analyze the next hundred moves.
- In capture-based games (such as chess), a position can often be evaluated relatively easily, such as by calculating who has a material advantage or more active pieces. In Go, there is often no easy way to evaluate a position. However a 6-kyu human can evaluate a position at a glance, to see which player has more territory, and even beginners can estimate the score within 10 points, given time to count it. The number of stones on the board (material advantage) is only a weak indicator of the strength of a position, and a territorial advantage (more empty points surrounded) for one player might be compensated by the opponent's strong positions and influence all over the board. Normally a 3-dan can easily judge most of these positions.
It was not until August 2008 that a computer won a game against a professional level player at a handicap of 9 stones, the greatest handicap normally given to a weaker opponent. It was the Mogo program, which scored this first victory in an exhibition game played during the US Go Congress. By 2013, a win at the professional level of play was accomplished with a four-stone advantage. In October 2015, Google DeepMind's program AlphaGo beat Fan Hui, the European Go champion and a 2 dan (out of 9 dan possible) professional, five times out of five with no handicap on a full size 19×19 board. AlphaGo used a fundamentally different paradigm than earlier Go programs; it included very little direct instruction, and mostly used deep learning where AlphaGo played itself in hundreds of millions of games such that it could measure positions more intuitively. In March 2016, Google next challenged Lee Sedol, a 9 dan considered the top player in the world in the early 21st century, to a five-game match. Leading up to the game, Lee Sedol and other top professionals were confident that he would win; however, AlphaGo defeated Lee in four of the five games. After having already lost the series by the third game, Lee won the fourth game, describing his win as "invaluable". In May 2017, AlphaGo beat Ke Jie, who at the time continuously held the world No. 1 ranking for two years, winning each game in a three-game match during the Future of Go Summit. In October 2017, DeepMind announced a significantly stronger version called AlphaGo Zero which beat the previous version by 100 games to 0.
In February 2023, Kellin Pelrine, an amateur American Go player, won 14 out of 15 games against a top-ranked AI system in a significant victory over artificial intelligence. Pelrine took advantage of a previously unknown flaw in the Go computer program, which had been identified by another computer. He exploited this weakness by slowly encircling the opponent's stones and distracting the AI with moves in other parts of the board. The tactics used by Pelrine have highlighted a fundamental flaw in the deep learning systems that underpin many of today's advanced AI. Although the AI systems can "understand" specific situations, they lack the ability to generalize in a way that humans find easy.
Software assistance
Main article: Go softwareAn abundance of software is available to support players of the game. This includes programs that can be used to view or edit game records and diagrams, programs that allow the user to search for patterns in the games of strong players, and programs that allow users to play against each other over the Internet.
Some web servers provide graphical aids like maps, to aid learning during play. These graphical aids may suggest possible next moves, indicate areas of influence, highlight vital stones under attack and mark stones in atari or about to be captured.
There are several file formats used to store game records, the most popular of which is SGF, short for Smart Game Format. Programs used for editing game records allow the user to record not only the moves, but also variations, commentary and further information on the game.
Electronic databases can be used to study life and death situations, joseki, fuseki and games by a particular player. Programs are available that give players pattern searching options, which allow players to research positions by searching for high-level games in which similar situations occur. Such software generally lists common follow-up moves that have been played by professionals and gives statistics on win–loss ratio in opening situations.
Internet-based Go servers allow access to competition with players all over the world, for real-time and turn-based games. Such servers also allow easy access to professional teaching, with both teaching games and interactive game review being possible.
In popular culture
Apart from technical literature and study material, Go and its strategies have been the subject of several works of fiction, such as The Master of Go by Nobel prize-winning author Yasunari Kawabata and The Girl Who Played Go by Shan Sa. Other books have used Go as a theme or minor plot device. For example, the novel Shibumi by Trevanian centers around the game and uses Go metaphors. Go features prominently in the Chung Kuo series of novels by David Wingrove, being the favourite game of the main villain.
The manga series Hikaru no Go and its anime adaptation, first released in Japan in 1998 and 2001 respectively, had a large impact in popularizing Go among young players, both in Japan and—as translations were released—abroad.
Similarly, Go has been used as a subject or plot device in film, such as Pi (π), A Beautiful Mind, Tron: Legacy, Knives Out, and The Go Master (a biopic of Go professional Go Seigen). 2013's Tôkyô ni kita bakari or Tokyo Newcomer portrays a Chinese foreigner Go player moving to Tokyo. In King Hu's wuxia film The Valiant Ones, the characters are color-coded as Go stones (black or other dark shades for the Chinese, white for the Japanese invaders), Go boards and stones are used by the characters to keep track of soldiers prior to battle, and the battles themselves are structured like a game of Go.
Go has also been featured as a plot device in a number of television series. Examples include Starz's science fiction thriller Counterpart, which is rich in references (the opening itself featuring developments on a Go board), and includes Go matches, accurately played, relevant to the plot. Also, in 2024 Netflix released the historical-fictional Korean series Captivating the King.
The corporation and brand Atari was named after the Go term.
Hedge fund manager Mark Spitznagel used Go as his main investing metaphor in his investing book The Dao of Capital. The Way of Go: 8 Ancient Strategy Secrets for Success in Business and Life by Troy Anderson applies Go strategy to business. GO: An Asian Paradigm for Business Strategy by Miura Yasuyuki, a manager with Japan Airlines, uses Go to describe the thinking and behavior of business men.
Psychological perspectives
A 2004 review of literature by Fernand Gobet, de Voogt and Jean Retschitzki shows that relatively little scientific research has been carried out on the psychology of Go, compared with other traditional board games such as chess. Computer Go research has shown that given the large search tree, knowledge and pattern recognition are more important in Go than in other strategy games, such as chess. A study of the effects of age on Go-playing has shown that mental decline is milder with strong players than with weaker players. According to the review of Gobet and colleagues, the pattern of brain activity observed with techniques such as PET and fMRI does not show large differences between Go and chess. On the other hand, a study by Xiangchuan Chen et al. showed greater activation in the right hemisphere among Go players than among chess players, but the research was inconclusive because strong players from Go were hired while very weak chess players were hired in the original study. There is some evidence to suggest a correlation between playing board games and reduced risk of Alzheimer's disease and dementia.
Arthur Mary, a French researcher in clinical psychopathology, reports on his psychotherapeutic approaches using the game of Go with patients in private practice and in a psychiatric ward. Drawing on neuroscience research and employing a psychoanalytic (Lacanian) and phenomenological approach, he demonstrates how drives are expressed on the goban. He offers some suggestions to therapists for defining ways of playing go that lead to therapeutic effects.
Analyses of the game
See also: Go and mathematicsIn formal game theory terms, Go is a non-chance, combinatorial game with perfect information. Informally that means there are no dice used (and decisions or moves create discrete outcome vectors rather than probability distributions), the underlying math is combinatorial, and all moves (via single vertex analysis) are visible to both players (unlike some card games where some information is hidden). Perfect information also implies sequence—players can theoretically know about all past moves.
Other game theoretical taxonomy elements include the facts
- Go is bounded by a finite number of moves and every game must end with a victor or a tie (although ties are very rare);
- the strategy is associative because every strategy is a function of board position;
- the format is non-cooperative (that is, it's not a team sport);
- positions are extensible, and so can be represented by board position trees;
- the game is zero-sum because player choices do not increase resources available, the rewards in the game are fixed and if one player wins, the other loses, and the utility function is restricted (in the sense of win/lose);
- however, ratings, monetary rewards, national and personal pride and other factors can extend utility functions, but generally not to the extent of removing the win/lose restriction, although Affine transformations can theoretically add non-zero and complex utility aspects even to two player games.
In the endgame, it can often happen that the state of the board consists of several subpositions that do not interact with the others. The whole board position can then be considered as a mathematical sum, or composition, of the individual subpositions. It is this property of Go endgames that led John Horton Conway to the discovery of surreal numbers.
In combinatorial game theory terms, Go is a zero-sum, perfect-information, partisan, deterministic strategy game, putting it in the same class as chess, draughts (checkers), and Reversi (Othello).
The game emphasizes the importance of balance on multiple levels: to secure an area of the board, it is good to play moves close together; however, to cover the largest area, one needs to spread out, perhaps leaving weaknesses that can be exploited. Playing too low (close to the edge) secures insufficient territory and influence, yet playing too high (far from the edge) allows the opponent to invade. Decisions in one part of the board may be influenced by an apparently unrelated situation in a distant part of the board (for example, ladders can be broken by stones at an arbitrary distance away). Plays made early in the game can shape the nature of conflict a hundred moves later.
The game complexity of Go is such that describing even elementary strategy fills many introductory books. In fact, numerical estimates show that the number of possible games of Go far exceeds the number of atoms in the observable universe.
Go also contributed to the development of combinatorial game theory (with Go infinitesimals being a specific example of its use in Go).
Comparisons to other games
Go begins with an empty board. It is focused on building from the ground up (nothing to something) with multiple, simultaneous battles leading to a point-based win. Chess is tactical rather than strategic, as the predetermined strategy is to trap one individual piece (the king). This comparison has also been applied to military and political history, with Scott Boorman's book The Protracted Game (1969) and, more recently, Robert Greene's book The 48 Laws of Power (1998) exploring the strategy of the Chinese Communist Party in the Chinese Civil War through the lens of Go.
A similar comparison has been drawn among Go, chess and backgammon, perhaps the three oldest games that enjoy worldwide popularity. Backgammon is a "man vs. fate" contest, with chance playing a strong role in determining the outcome. Chess, with rows of soldiers marching forward to capture each other, embodies the conflict of "man vs. man". Because the handicap system tells Go players where they stand relative to other players, an honestly ranked player can expect to lose about half of their games; therefore, Go can be seen as embodying the quest for self-improvement, "man vs. self".
See also
- Games played with Go equipment
- List of books about Go
- List of top title holders in Go
- Sensei's Library
Notes
- Game complexity can be difficult to estimate. The number of legal positions (state-space complexity) for chess has been estimated at anywhere between 10 and 10; in 2016 the number of legal positions for 19x19 Go was calculated by Tromp and Farneback at ~2.08×10. Alternately, a measure of all the alternatives to be considered at each stage of the game (game-tree complexity) can be estimated with b, where b is the game's breadth (number of legal moves per position) and d is its depth (number of moves or plies per game). For chess and Go the comparison is very rough, ~35 ≪ ~250, or ~10 ≪ ~10
- Eyes and other complications may need to be considered when counting liberties
- Whether or not a group is weak or strong refers to the ease with which it can be killed or made to live. See this article by Benjamin Teuber, amateur 6 dan, for some views on how important this is felt to be.
- Exceptionally, in Japanese and Korean rules, empty points, even those surrounded by stones of a single color, may count as neutral territory if some of them are alive by seki. See the section below on seki.
- In game theoretical terms, seki positions are an example of a Nash equilibrium.
- A full explanation of the eternal life position can be found on Sensei's Library, it also appears in the official text for Japanese Rules, see translation.
- Roughly, one has the time to play the game and then a little time to finish it off. Time-wasting tactics are possible in Go, so that sudden death systems, in which time runs out at a predetermined point however many plays are in the game, are relatively unpopular (in the West).
- Literally in Japanese byōyomi means 'reading of seconds'.
- Typically, players stop the clock, and the player in overtime sets his/her clock for the desired interval, counts out the required number of stones and sets the remaining stones out of reach, so as not to become confused. If twenty moves are made in time, the timer is reset to five minutes again.
- In other words, Canadian byoyomi is essentially a standard chess-style time control, based on N moves in a time period T, imposed after a main period is used up. It is possible to decrease T, or increase N, as each overtime period expires; but systems with constant T and N, for example 20 plays in 5 minutes, are widely used.
- Kaku Takagawa toured Europe around 1970, and reported (Go Review) a general standard of amateur 4 dan. This is a good amateur level but no more than might be found in ordinary East Asian clubs. Published current European ratings would suggest around 100 players stronger than that, with very few European 7 dans.
- European Go has been documented by Franco Pratesi, Eurogo (Florence 2003) in three volumes, up to 1920, 1920–1950, and 1950 and later.
- See Overshoot in Western typography for similar subtle adjustment to create a uniform appearance.
- While chess position evaluation is simpler than Go position evaluation, it is still more complicated than simply calculating material advantage or piece activity; pawn structure and king safety matter, as do the possibilities in further play. The complexity of the algorithm differs per engine.
- Lists of such programs may be found at Sensei's Library or GoBase.
- Lists of Go servers are kept at Sensei's Library and the AGA website
- The British Go Association provides a list of teaching services
- A list of books can be found at Sensei's Library
- A list of films can be found at the EGF Internet Go Filmography
- It has been said that the number of board positions is at most 3 (about 10) since each position can be white, black, or vacant. Ignoring (illegal) suicide moves, there are at least 361! games (about 10) since every permutation of the 361 points corresponds to a game. See Go and mathematics for more details, which includes much larger estimates.
This estimate, however, is inexact for two reasons: first, both contestants usually agree to end the game long before every point has been played; second, after a capture it may happen that an already played point is played again, even repetitively so in the case of a kō-battle.
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Further reading
Introductory books
- Bradley, Milton N. Go for Kids, Yutopian Enterprises, Santa Monica, 2001 ISBN 978-1-889554-74-7.
- Ogawa, Tomoko; Davies, James (2000). The Endgame. Elementary Go Series. Vol. 6 (2nd ed.). Tokyo: Kiseido Publishing Company. ISBN 4-906574-15-7.
- Seckiner, Sancar. Chinese Go Players, 6th article of the main book Budaha, Efil Yayinevi, Ankara, Feb. 2016, ISBN 978-605-4160-62-4.
- Shotwell, Peter. Go! More than a Game, Tuttle Publishing, 4th ed. 2014, ISBN 978-0-8048-3475-9.
Historical interest
- De Havilland, Walter Augustus (1910), The ABC of Go: The National War Game of Japan, Yokohama, Kelly & Walsh, OCLC 4800147
- Korschelt, Oscar (1966), The Theory and Practice of Go, C.E. Tuttle Co, ISBN 978-0-8048-0572-8
- Smith, Arthur (1956) , The Game of Go: The National Game of Japan, C.E. Tuttle Co, OCLC 912228
- Definitions from Wiktionary
- Media from Commons
- Quotations from Wikiquote
- Texts from Wikisource
- Textbooks from Wikibooks
- Travel guides from Wikivoyage
- Data from Wikidata