251,270 Pages

Thirty-First Army (Japan)
Japanese Prisoners of War at Guam - 15 August 1945
Japanese POWs at Guam at time of the surrender of Japan
Country Empire of Japan
Branch Imperial Japanese Army
Service history
Active February 18, 1944 - August 15, 1945
Role Corps
Battles Operation Hailstone
Battle of Saipan
Battle of Guam

The Japanese 31st Army (第31軍 Dai-sanjyū-ichi gun?) was an army of the Imperial Japanese Army during World War II.


The Japanese 31st Army was formed on February 18, 1944 under the Imperial General Headquarters as a garrison force to contest landings by Allied forces in the Japanese South Seas Mandate island-by-island, and to inflict such losses in a war of attrition that it would deter an American invasion of the Japanese home islands. The South Seas Mandate was divided into three sections (Northern Mariana Islands, southern Mariana Islands, and Truk). The 80,000 man Japanese 31st Army was initially headquartered on Truk.

After Operation Hailstone, the Japanese garrison on Truk was isolated as American forces continued their advance towards Japan by invading other Pacific islands. Cut off, the Japanese forces on Truk and other central Pacific islands ran low on food and faced starvation before Japan surrendered in August 1945. (Stewart, 1986)

The garrisons in the Marianas were largely annihilated at the Battle of Saipan and Battle of Guam.

List of commandersEdit

Commanding officerEdit

Name From To
1 General Hideyoshi Obata 25 February 1944 11 August 1944
2 Major General Yoshitomo Tamura 11 August 1944 22 August 1944
3 Lieutenant General Toshisaburo Mugikura 22 August 1944 1 September 1945

Chief of StaffEdit

Name From To
1 Major General Keiji Igeta 25 February 1944 6 July 1944
2 Major General Yoshitomo Tamura 14 July 1944 11 August 1944


  • Frank, Richard B (1999). Downfall: The End of the Imperial Japanese Empire. New York: Random House. ISBN 0-679-41424-X. 
  • Jowett, Bernard (1999). The Japanese Army 1931-45 (Volume 2, 1942-45). Osprey Publishing. ISBN 1-84176-354-3. 
  • 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. ISBN 1-84176-882-0. 
  • Denfeld, D. Colt (1997). Hold the Marianas: The Japanese Defense of the Mariana Islands. White Mane Pub. ISBN 1-57249-014-4. 
  • Goldberg, Harold J. (2007). D-day in the Pacific: The Battle of Saipan. Indiana University Press. ISBN 0-253-34869-2. 
  • Jones, Don (1986). Oba, The Last Samurai. Presidio Press. ISBN 0-89141-245-X. 

External linksEdit

This page uses Creative Commons Licensed content from Wikipedia (view authors).
Community content is available under CC-BY-SA unless otherwise noted.