Hitoshi Imamura
At the opening of the Allied offensives, their estimates of Japanese strength on Bougainville varied widely, ranging between 45,000 and 65,000 Army, Navy, and labour personnel. These forces constituted the Japanese 17th Army, commanded by General Harukichi Hyakutake. Hyukatake reported to General Hitoshi Imamura, commander of the Japanese Eighth Area Army, headquartered at Rabaul on New Britain Island. Naval command at Rabaul was the responsibility of Vice Admiral Jinichi Kusaka, commander Southeast Area Fleet. The level of cooperation between these two officers was greater than that usually found between the branches of the Japanese armed forces. On Bougainville, the Japanese forces consisted of the following formations: the 17th Infantry Group – consisting of the 81st Infantry Regiment and the III Battalion, 53rd Infantry Regiment under Major General Kesao Kijima, and elements of the 6th Division. The 17th Infantry occupied northern Bougainville, while the 6th had responsibility for the island south of Tarina.