In 1966, the JASDF transport fleet was composed primarily of Curtiss C-46 Commandos, a retired midwar American design built in large numbers before the end of World War II. While relatively capable for its time, the C-46 did not fare well in comparison to newer aircraft such as the Lockheed C-130 Hercules, and the JASDF therefore elected to replace it with a domestically-designed and -manufactured transport aircraft.