April 15, 1945, 11 Hayates attacked US airfields on Okinawa, destroying many aircraft on the ground. In the final year of the war the Ki-84, the Ki-100 (essentially a radial-engined version of the inline-powered Kawasaki Ki-61) and Kawanishi's N1K2-J were the three Japanese fighters best suited to combat the newer Allied fighters. Variants Ki-84-a: Prototype. Ki-84-b: Evaluation model. Ki-84-c: Pre-production model. Ki-84-I Ko: Armed with 2 × 12.7 mm Ho-103 machine guns and 2 × 20mm Ho-5 cannons in wings (most widely produced version). Ki-84-I Otsu: Armed with 4 × 20 mm [[Ho-5 cannon. (Limited production run, may not have equipped a full Sentai) Ki-84-I Hei: Armed with 2 × 20 mm Ho-5 cannon and 2 × 30 mm Ho-155 cannon in wings. Ki-84-I Tei: Night fighter variant of Ki-84 Otsu. Equipped with an additional Ho-5 20mm cannon (300 shells) placed at 45 degree angle behind the cockpit in Schräge Musik configuration. Rare variant, 2 built. Ki-84-I Ko - Manshu Type: Manufactured in Manchukuo for Manshūkoku Hikōki Seizo KK by Nakajima License. Ki-84-II: Sometimes known as the 'Hayate-Kai', the Ki-84-II had certain duralumin components replaced with ones made of wood and plywood, mainly concerning the rear fuselage, tail unit elements, wing tips, push-pull rods and other, minor components. This model was produced with the designations Ko, Otsu and Hei depending on the armament. Ki-84-III: A planned conversion of the Ki-84 into a high-attitude interceptor after development of the Ki-87 prototype was delayed. Replaced the Homare engine with a 2450 hp Nakajima Ha-44 12 Ru air cooled radial engine with a turbo-supercharger mounted under the fuselage. The airframe remained unchanged, aside from the engine mountings to support the larger diameter engine. The airplane did not progress beyond the design stage. Ki-84 Sa Go: Oxygen injection system replacing the traditional water-methanol injection system to improve high attitude performance. No prototypes were built. Ki-84-N: 1st high-altitude interceptor variant of the Ki-84, with a 2500 hp Nakajima Ha-219 air cooled radial engine and with wing area increased to 249.19 square feet. The Ki-84-N production model was assigned to the Kitai 'Ki-117'. Neither aircraft left the design stage before the war's end. Ki-84-P: 2nd high-altitude interceptor variant of the Ki-84, with a 2500 hp Nakajima Ha-219 air cooled radial engine and with wing area increased to 263.4 square feet. Cancelled in favor of further development of the Ki-84-R, which was proving to be a less