TYPE: Float seaplane fighter
ACCOMMODATION: Pilot only
POWER PLANT: One Mitsubishi MK4E “Kasi 14” radial engine, rated at 1,400 hp
PERFORMANCE: 304 mph at 18,700 ft
COMMENT: Satisfied with the results of the flight trial progamme of the prototypes of the Kawanashi N1K1 the Imperial Japanese Navy ordered the aircraft into quantity production as the Navy Fighter Seaplane “Kyofu Model 11”, and deliveries of production aircraft began in spring of 1943 following the completion of eight prototypes and service trials aircraft. But production was slow in gaining tempo and by December 1943, when the delivery rate had reached fifteen aircraft per month, the decision was taken to cease manufacture of the “Kyofu” and the last N1K1 was delivered in March 1944. This decision did not indicate any misgiving on the aircraft’s capability but merely reflected the fact that the war had taken an unfavourable turn for Japan which no longer needed a fighter to support offensive operations.
The war situation was also reflected in the operational use of the aircraft in a defensive role and N1K1s (Allied code name “Rex”) were assigned as interceptors in the Borneo Area of Action. Late in the war the “Kyofu” was assigned to similar duties with the Otsu Kokutai operating from Lake Biwa as an air defence unit (Ref.: 1).