Japanese Naval Air Force Imperial Japanese Navy Air Service - IJANS for short, jap. Dai-Nippon Teikoku Kaigun Koku-tai) were formed as early as 1910, but their very intensive development took place mainly in the 1920s and 1930s, and the main advocate of their development was Admiral Isoroku Yamamoto. At the outbreak of the Pacific War IJANS were able to deploy approx. 1,830 airplanes in the first line, including approx. 660 fighters, approx. 330 on-board bombers and torpedo planes, approx. 240 bomber planes operating from land bases and approx. 520 seaplanes. The basic types of machines include the famous Mitsubishi A6M Zeke fighters, but also the Aichi D3A dive bomber, the Nakajima B5N on-board torpedo plane and the Mitsubishi G4M sea bomber. The basic organizational unit of in-flight aviation was the air group (Japanese kouktai, later Koku-sentai), which numbered up to 80-90 aircraft. The lower-level unit was a hikotai (the equivalent of a squadron) with 9 to 16 machines. When the war in the Pacific began, the Japanese naval aviators were highly trained and often clearly superior to the Allied pilots in this matter. However, the wrong training system meant that, along with the increasing losses during the war, there was no one to replace these great airmen. As a result, in the years 1944-1945 Japanese naval pilots were clearly inferior to their American opponents in terms of skills.