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.
Drea, Edward J. (1998). "Japanese Preparations for the Defense of the Homeland & Intelligence Forecasting for the Invasion of Japan". In the Service of the Emperor: Essays on the Imperial Japanese Army. University of Nebraska Press. ISBN0-8032-1708-0.
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.
Skates, John Ray (1994). The Invasion of Japan: Alternative to the Bomb Downfall. New York: University of South Carolina Press. ISBN0-87249-972-3.
Zaloga, Steven L (2010). Defense of Japan. Oxford, U.K.: Osprey Publishing. ISBN1-58545-044-8.