Derived from the Ki-61 Hein “Tony” the Ki-100 flew for the first time in February 1945 and without the need for the heavy coolant radiator and other fittings required for a liquid-cooled engine, was lighter than the Ki-61-II thus reducing the wing loading. This had an immediate positive effect on the flight characteristics, enhancing landing and takeoff qualities as well as imparting increased maneuverability, including a tighter turning circle. Pleased by the flight characteristics of the plane the model was ordered to be put in production and the first 271 of the airframes were remanufactured from Ki-61-II Kai and Ki-61-III airframes. Later 118 of the Ki-100 II with an ‘all around view’ canopy were produced. The Ki-100 was the Imperial Japanese Army’s last fighter and in the hands of a skilled pilot was more than a match for allied fighters.