Kawasaki Ki-100

The Kawasaki Ki-100 (キ100) is a single-seat single-engine monoplane fighter aircraft used by the Imperial Japanese Army Air Service (IJAAS) during World War II. The Japanese Army designation was "Type 5 Fighter" (五式戦闘機, Go-shiki sentouki; or abbreviated as Goshikisen). It did not have an Allied code name.

In early 1945, 275 Ki-100s were modified from Ki-61s as an emergency measure to accept a 14-cylinder Mitsubishi Ha-112-II radial engine in place of the original Kawasaki Ha-40 inverted V-12 inline engine, resulting in one of the best interceptors used by the Army during the war. It combined excellent power and maneuverability, and from the first operational missions in March 1945 until the end of the war, it performed better than most IJAAS fighters against both United States Army Air Forces B-29 Superfortress bombers and P-51 Mustang fighters, as well as U.S. Navy F6F Hellcat carrier fighters.

A newly built variant, the Ki-100-Ib, was produced with a cut down rear fuselage during the last months of the war which equipped five home defence sentai. High-altitude performance was further improved with the final variant, the Ki-100-II, however only three of these were produced before the war ended and this final variant never saw operational service.