The Mitsubishi Ki-46 Dinah was the most important Japanese reconnaissance aircraft of the Second Wold War and was aerodynamically one of the cleanest and most efficient piston-engine aircraft ever built. The Ki 46-II was the major operational variant of the Dinah series, first flown in March 1941, with deliveries to the Japanese Army Air Force commencing in July 1941.  It remained in production until late 1944.