Japanese Eighteenth Army
Hatazo Adachi signed surrender
General Adachi surrendering
Active 1942-11-09 - 1945-08-15
Country Empire of Japan
Branch Imperial Japanese Army
Type Infantry
Role Corps
Garrison/HQ New Guinea
Nickname ( Fierce?)
Engagements New Guinea campaign

The Japanese 18th Army (第18軍 Dai-jyūhachi gun?) was an army of the Imperial Japanese Army during the World War II.


The Japanese 18th Army was formed on 9 November 1942 under the Japanese Eighth Area Army of the Southern Expeditionary Army Group for the specific task of opposing landings by Allied forces in Japanese-occupied New Guinea.

New Guinea campaignEdit

Main article: New Guinea campaign

The 18th Army contained the IJA 20th Division and IJA 41st Division, both of which arrived in New Guinea safely. However, the IJA 51st Division, including Adachi and his senior staff, came under Allied air attack while en route from their supply base at Rabaul to Lae, in the Battle of the Bismarck Sea. All eight transport ships and four destroyers were sunk with the loss of 3,664 men, and only 2,427 men of the Division were rescued.

Operation Cartwheel, an Allied master plan implemented from mid-1943, progressively severed the supply lines between Rabaul and frontline Japanese forces. Key defeats included the withdrawal of the Imperial Japanese Navy from the Solomon Islands campaign, followed by landings on New Britain, as well as Aitape and Hollandia, in April 1944.

Adachi's forces were badly affected by tropical diseases like malaria, heat exhaustion and malnutrition for the remainder of the war, despite Adachi's efforts to achieve some form of self-sufficiency by planting crops and giving priority in rations to the sick. As ammunition began to run low, many of Japanese field commanders resorted to banzai charges, rather than surrender.

By the end of the war in September 1945, most of his forces had been annihilated. Of Adachi's original 140,000 men, barely 13,000 were still alive when the war ended. The remnants of the Japanese 18th Army surrendered to the Australian 6th Division at Wewak, New Guinea.

List of CommandersEdit

Name From To
Commanding officer General Hatazō Adachi 9 November 1942 15 August 1945
Chief of StaffLt. General Kane Yoshihara 9 November 1942 15 August 1945



  • Hayashi, Saburo (1959). Kogun: The Japanese Army in the Pacific War. Marine Corps. Association. ASIN B000ID3YRK. 
  • Drea, Edward J. (2003). "Adachi Hatazo: A Soldier of His Emperor". In the Service of the Emperor: Essays on the Imperial Japanese Army. Bison Books. ISBN 978-0803266384. 
  • Fuller, Richard (1992). "Adachi Hatazo". Shōkan: Hirohito's Samurai. London: Arms and Armour Press. ISBN 1-85409-151-4. 

External linksEdit

zh:第18軍 (日本陸軍)