Yoshimitsu accomplished the unification of the Southern and Northern Courts in 1392, and then defeated Yoshihiro OUCHI in the Oei War in 1399 who had individually carried on private trade.
義満は1392年に南北朝合一を行い、1399年（応永6）には独自に私貿易を行っていた大内義弘を応永の乱で討つ。