The N1K2-J was a complete redesign begun only four days after the “Shindens” first test flight, to address the N1KI-J’s major defects, primarily the mid-mounted wing and long landing gear. The wings were moved to a lower position, which permitted the use of conventional landing gear legs. The fuselage was lengthened, the tail redesigned, and the whole aircrft was made much simpler to produce and to use fewer critical materials in short supply at the time. The Homare engine was retained, since there was no alternative, even though it’s reliability problems had not been fully corrected. A prototype flew on 1 January 1944 and was rushed into production after Navy trials in April. The aircraft was named the “Shinden-Kai”, Kai standing for “modified”.
The aircraft entered service in early 1944 and proved highly effective against American fighters, though mechanically unreliable. The engine was difficult to maintain and, like the complicated undercarriage, plagued by frequent failures. N1K1-J aircraft were used effectively over Formosa, the Philippines and later, Okinawa. Before production was switched to the improved N1K2-J, 1,007 aircraft were produced, including prototypes.
Problems resulted in very few aircraft being produced, but the Shinden-Kai proved to be one of the best dogfighters fielded by either side. Along with high speed, the fighters were very agile, with a roll rate of 82 deg/sec @ 240 mph (390 km/h). Their weaponry was very effective, comprising of four 20 mm cannons in the wings and a pair of machine-guns in the nose. As a bomber interceptor, it was less successful, because of a poor rate of climb and reduced engine performance at high altitude.
Because of production difficulties, and damage caused by B-29 Superfortress raids on Japanese factories, only 415 fighters were produced. Consequently, N1K-J fighters were mainly used by units like the elite IJN 343rd Air Group (343 Kokutai) commanded by Minoru Genda. The new Shinden was principally involved in the battles fought in the last year of the war. The 343 Kokutai (343rd Naval Fighter Group) was constituted on 25 December 1944 by Captain Minoru Genda, the veteral naval aviator who had previously masterminded the attack on Pearl Harbor. Another unit bearing the 343 number had previously existed, but was disbanded in July 1944. The new 343rd Kokutai consisted of the best pilots and the best fighters available. One of the more prominent 343rd Kokutai pilots was Kaneyoshi Muto, reputed to have single-handedly shot down four Hellcats. The unit was also equipped with the new C6N Saiun “Myrt” long-range reconnaisance aircraft.
