the kawasaki t-4 is a japanese subsonic intermediate jet trainer aircraft developed and manufactured by the commercial conglomerate kawasaki heavy industries. its sole operator is the japan air self-defense force (jasdf), in part due to historic restrictions on the exporting of military hardware. in addition to its primary training mission, the t-4 has been used by the jasdf's blue impulse aerobatic team as well as liaison duties with most fighter units. the first xt-4 prototype flew on 29 july 1985, while the first production aircraft was delivered during september 1988.