Hitachi Kokuki KK formed May 1939 to operate factories at Omori, Tachikawa and Tokyo-Haneda acquired by merger of parent Hitachi Seisakusho KK with Tokyo Gasu Denki Kogyo KK. New plant built at Chiba became principal aircraft assembly centre. Aircraft built under licence included K2Y2, K5Y1, K9W1 and A6M2-K, and Hitachi was No. 3 among wartime engine producers. Original designs included TR.l twin-engined light transport (Tokyo Gasu design) and T.2 biplane trainer.