Kango trade started in 1401 when Yoshimitsu ASHIKAGA proposed to start the trade with Ming by dispatching a Buddhist monk Soa and a merchant in Hakata Koitomi and received 'Eiraku kangofu' from the envoy of Ming.
足利義満は、応永8年（1401年）に僧の祖阿と博多商人の肥富を派遣し、明との交易を申し入れ、明の使者から「永楽の勘合符」を得て、勘合貿易が始まる。