Formed 6 December 1917 by retired engineer (ex-Imperial Navy Lt.) Chikuhei Nakajima and Seibei Kawanishi as Nihon Hikoki Seisakusho KK (Japanese Aeroplane Manufacturing Work Co. Ltd). Partners split December 1919, Kawanishi forming own company; Nakajima obtained backing of mighty Mitsui in forming Nakajima Hikoki KK (Nakajima Aeroplane Co. Ltd). Continued unchanged during massive growth to become No. 1 producer in Second World War with 4 airframe plants (Ota, Koizumi, Handa and Utsonomiya) and 4 engine plants, but on 1 April 1945 transferred to state control as 1st Munitions Arsenal. In 1920-39 Nakajima built more than 6,000 aircraft, almost all for Imperial Army and Navy and including several licensed designs (Bre 14, Avro 504, NiD 29, W33, Gambet, etc.). Deliveries 1920-45 totalled 29,760. Major programmes for Second World War included Ki-27, Ki-43 Hayabusa, Ki-44 Shoki and Ki-84 Hayate fighters, B5N and B6N Tenzan torpedo bombers, C6N Saiun reconnaissance aircraft, Ki-49 Donryu heavy bomber, J1N Gekko escort and night fighter and E8N reconnaissance seaplane. Nakajima also made large numbers of aircraft designed by others, notably A6M, Ki-21, G3M, P1Y and L2D, handling entire programme for A6M2-N fighter seaplane. Post-war, major assets were managed by Fuji.