The Kawanishi J6K1 Jinpu was a purpose-built land based interceptor designed for the Japanese navy, but that didn't enter production because of the success of the same company's N1K2-J.
The J6K1 was developed from the J3K1 of 1942. This was to have been powered by the Mitsubishi MK9A radial engine, and would have been a fairly standard looking radial engined fighter, but it didn't progress beyond the early design stage.
Work on the J6K1 began in 1943. This time the aircraft was to use the Homare 42 engine, the design progressed far enough to receive a popular name, the Jinpu (Squall). The new interceptor would have been very heavily armed, with two 30mm cannon and two 13.2mm machine guns, and with a good top speed of 426mph.
The J6K1 never entered production. Kawanishi had also produced the N1K float plane fighter, which was followed by a normal landed based version, the N1K1-J. This was then superseded by the N1K2-J Shiden, a smaller aircraft than the J6K, armed with four 20mm cannon and with sufficiently impressive performance to meet the Navy's requirements. The N1K2-J was produced in large numbers, while the J6K1 was cancelled.
Engine: Homare 42
Wing span: 41ft 0 1/8in
Length: 33ft 22 11/32in
Loaded Weight: 9,634lb
Max Speed: 426mph at 32,810ft
Armament: Two 30mm cannon and two 13.2mm machine guns