In 1940, the Imperial Japanese Navy began development of the Kawanishi N1K1 Kyofu. Also known as 'Mighty Wind' or 'Rex' by the Allied forces, the Kyofu was a close air support floatplane fighter that was designed for amphibious landings in areas where land-based fighters could not. However, by the time trials were complete and production commenced, the tide of war had changed and the need for such aircraft had diminished. By 1944, only 97 had been built and were used primarily in a defensive role. The 'Rex' weighed 6,067 pounds empty and could reach a maximum speed of 304 mph.