I know but I am a bit surprised they didn't keep the aero engine tech in house. The Japanese fighters are all American. Japan has the technical know how necessary to produce any jet engine and any advanced fighter jet, yet they did not. To the very least Japan should have kept an indigenous passenger airliner industry, no doubt if they wanted it would rival anything the Rolls Royce, Pratt&Whitney, GE, Boeing and Airbus can produce. The Boeing-Airbus duopoly could easily be a trio poly.
Not strictly true with aero-engine tech.
Their P1 Maritime Patrol Aircraft has indigenous engines and they are developing a 5th generation fighter engine for their new-gen fighter.
Their next-gen fighter F-X is due for service in 2031 and they have already run the XF9 engine that will power it.
The Japanese have always retained the option to break away from the USA. They have the missile tech and can produce nuclear bombs in 12-18 months in an emergency situation.
PS - The F-2 is really a Japanese fighter with a US engine, although based on F-16 airframe. The USA even borrowed the airframe technology that Japan developed for it.