The Mitsubishi F-15J/DJ Eagle is a twin-engine, all-weather air superiority fighter based on the McDonnell Douglas F-15 Eagle in use by the Japan Air Self-Defense Force (JASDF). The F-15J was produced under license by Mitsubishi Heavy Industries. The subsequent F-15DJ and F-15J Kai variants were also produced. Japan is the largest customer of the F-15 Eagle outside the United States. In addition to combat, F-15DJ roles include training. The F-15J Kai is a modernized version of the F-15J.
In June–July 1975, the Japan Defense Agency (JDA, now Ministry of Defense) examined the McDonnell Douglas F-15 Eagle as one of the 13 candidates for the replacement of the F-104J/DJ Starfighter and F-4EJ Phantom II. A single-seat F-15C and a twin-seat F-15D were evaluated at Edwards Air Force Base, and in December 1975, the F-15 was announced the winner, with the government intending to purchase 187 F-15J/DJs. By April 1978, Mitsubishi Heavy Industries was designated as the primary contractor and licensing for the F-15C/D was achieved.