Article snapshot taken from Wikipedia with creative commons attribution-sharealike license.
Give it a read and then ask your questions in the chat.
We can research this topic together.
Japanese Thirtieth Army
Kwantung Army HQ in Xinjing, which also housed the IJA 30th Army HQ
The Japanese 30th Army was initially raised on July 30, 1945 in the Manchukuo capital of Xinjing. As the war situation on the Pacific front grew increasingly desperate for Japan, the Imperial Japanese Army transferred more and more experienced divisions out of Manchukuo to other fronts. By early 1945, the vaunted Kwantung Army was largely hollowed out, and indications of a buildup of SovietRed Army forces on the borders on Mengjiang and Manchukuo were alarming. The Japanese 30th Army was assigned to the Japanese Third Area Army, and based in southern Manchukuo, but it was raised only days before the beginning of the Soviet invasion of Manchuria, and its force of under-armed and untrained raw recruits, reservists and civilian militia were absolutely no match for the experienced battle-hardened Soviet armored divisions. After a brief struggle at Xinjing (during which time the remnants of the Manchukuo Imperial Guard also defected to the Soviet side, the Japanese 30th Army surrendered. Most of its survivors became Japanese POWs in the Soviet Union, many of whom died under harsh conditions in Siberia and other parts of the Soviet Union.
Frank, Richard B (1999). Downfall: The End of the Imperial Japanese Empire. New York: Random House. ISBN0-679-41424-X.
Jowett, Bernard (1999). The Japanese Army 1931-45 (Volume 2, 1942-45). Osprey Publishing. ISBN1-84176-354-3.
Madej, Victor (1981). Japanese Armed Forces Order of Battle, 1937-1945. Game Publishing Company. ASIN: B000L4CYWW.
Marston, Daniel (2005). The Pacific War Companion: From Pearl Harbor to Hiroshima. Osprey Publishing. ISBN1-84176-882-0.
Glantz, David (2003). The Soviet Strategic Offensive in Manchuria, 1945 (Cass Series on Soviet (Russian) Military Experience, 7). Routledge. ISBN0-7146-5279-2.