This city gave popular name to Imperial Navy’s Dai-Ichi Kaigun Koku Gijitsusho (1st Technical Air Arsenal), whose designs were usually assigned to established manufacturers for series production, though some were also built by Dai-Juichi (11th) naval air arsenal at Hiro. Produced 6 prototype seaplanes 1916-18, 1 (Rogo-Ko) 2-seat recon (220-hp HS8b) being built by Aichi/Nakajima (219) 1918-20. In 1920-40 about 1,500 built of 10 designs of biplane trainer, mostly seaplanes, and K5Y (December 1933) was mass-produced, 5,770 by late 1944. Smaller numbers of recon aircraft included 126 E14Y monoplane seaplanes foldable for service aboard submarines. Small numbers built of bombers and flying-boats. B4Y biplane carrier-based torpedo bomber (late 1935) built mainly by Mitsubishi (135 of 205 total). D4Y Suisei (Comet) carrier-based dive-bomber (December 1940) was major type, 2,038 built, mainly by Aichi, 1942-5. Potentially one of best Japanese wartime aircraft, P1Y flown August 1943, 1,098 built, 996 by Nakajima. D3Y Myojo and R2Y Keiun never reached production, but MXY-7 suicide aircraft did (852, all by naval air arsenals).