The McDonnell Douglas - 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 along with McDonnell Douglas. The subsequent F-15DJ and F-15J J-MSIP (MSIP Configuration II Aircraft)[2][3][4][5] variants were also produced. Japan is the largest customer of the F-15 Eagle outside the United States.[6] In addition to combat, F-15DJ roles include training. The F-15J Kai is a modernized version of the F-15J.[7][8] Kai was an early designation that has gradually subdivided; nowadays, Japan no longer uses 'kai' to refer to newly upgraded F-15Js. Instead, Japanese predominantly use J-MSIP or F-15MJ.