Kawanishi N1K2-J Shiden-Kai (George)
Technical Information

Background
The Kawanishi N1K2-J Shiden-Kai meaning "Violet Lightning, Improved" was a derivative of the N1K1 Kyofu (Rex) floatplane fighter and N1K1-J Shiden fighter. Produced for the Imperial Japanese Navy (IJN) between December 1943 until July 1945. The Shiden-Kai proved to be one of the best all-round fighter aircraft of the Pacific War. Allied code name "George". The initial land based fighter version was designated N1K1-J Model 11 Shiden.

A unique design feature was wing flaps which operated automatically to increase lift when necessary during extreme maneuvers. The device, operated with electricity and oil pressure using a U-shaped tube containing mercury, was an important factor in the aircraft's maneuverability in combat. The N1K1-J Shiden and N1K2-J had a single large drop tank under the fuselage.

Wartime History
The N1K2-J Shiden-Kai were deployed in Japan for homeland defense operated by 343 Kōkūtai (343 Air Group) and Yokosuka Kōkūtai (Yokosuka Air Group) until the end of the Pacific War. In combat, the Shiden-Kai did not have sufficient high altitude performance effectively intercept B-29 Superfortress formations at high altitude, primarily due to engine difficulties.

N1K2-J Model 21 (George 21) Shiden-Kai
The modified and improved version that followed was designated Shiden-Kai meaning "Violet Lightning" Model 21 or Shiden 21 Gata or N1K2-J Shiden-Kai (Violet Lightning, Improved). Allied code name "George". Later, designated "George 21" to differentiate it from the N1K1-J Shiden code named "George 11". The first 100 planes assembled at Naruo could be armed with two 30 kg bombs or 60 kg bombs or two 250 kg bombs on external wing mounts.

N1K2-J Model 21 Kou / N1K2-J Kou / N1K2-Ja Shiden-Kai (George 21)
Starting with the 101st plane built at Naruo, modified to permit carrying four 30kg or 60 kg bombs or two 250 kg bombs on external wing mounts. This model was designated the Shiden Model 21 Kou (N1K2-J Kou or N1K2-Ja in English). Allied code name "George". Later, designated "George 21" to differentiate it from the N1K1-J Shiden code named "George 11". No specific Allied code name was created for the N1K2-Ja variant.

N1K2-Ja and Shiden Model 21 Kou are more detailed and specific terms for those models. These detailed terms probably did not appear on the plane's dataplates and may not have appeared in log books. The use of terms like N1K2-Ja and Shiden Model 21 Kou were more often used in technical, training and maintenance reports. There is a possibility that these detailed designations are of postwar origin and were never used during the Pacific War by the Japanese.

Production
A total of 400 Sinden-Kai were built before the end of the Pacific War. Production was slow due to production problems and parts shortages due to U.S. bombing raids. Factories that were to build the N1K2-J, included Kawasaki at Naruo, Aichi, Mitsubishi, Hiro Naval Depot, Omura Naval Depot. Also, Showa Aircraft Co., Ltd planned production and built a single Showa N1K2-J Model 21 by early August 1945.

The N1K2-J was produced in December 1943 until July 1945, with deliveries to the navy as follows:
December 1943 = 1 plane
January 1944 to December 1944 = 67 planes
January 1945 to July 1945 = 332 planes
Total = 400

Thanks to Jim Long for additional information

Technical Details (N1K2-J Shiden-Kai)
Crew  One (pilot)
Engine  Nakajima Homare 21, Ha 45 Model 21 18-cylinder air-cooled radial engine (1,820 hp) with a four bladed propeller
Span  12 m (39' 4.5")
Length  9.35m (30' 8")
Height  3.96m (13')
Maximum Speed  370 mph
Range  805 km
Armament  4 x 20mm Type 99 Mark 2 machine guns with 225 rounds per gun in the wings
Bombload  2 x 250 kg / 550 lb bombs on under wing hard points or centerline 323 L (85 gal) drop tank