In 1404, he started Japan-Ming trade that took the form of tribute to the Ming emperor. He also was able to suppress Japanese pirates (however, before the Ming's government could dispatch an envoy to convey the emperor's gratitude to the Japanese government, the Seinan War broke out in Ming, Emperor Jianwen abdicated, and Emperor Yongle took the throne).
明の皇帝に朝貢する形式をとった勘合貿易を1404年（応永11年）から始め、また明に要請されて倭寇を鎮圧した（なお、返礼の使者を送るまでに靖難の変が起き、建文帝から永楽帝に皇帝が変わっていた）。