Expedition to Tsushima
To strike the pirates at their base, Yi Jong-mu attacked Tsushima with some 200 ships; trade was later allowed under the 1443 treaty.
申叔舟 [撰] · Public domain · Source
In the fifth month of 1419 Japanese pirates raided Biin in Chungcheong and Haeju in Hwanghae. Sejong had been on the throne only a year, and military command still lay with the retired king Taejong, who led the decision to attack. It is also called the Gihae Eastern Expedition, after the year’s name.
Yi Jong-mu, as supreme field commander, sailed from Geoje in the sixth month with 227 warships and over 17,000 men. On Tsushima he burned or captured some 120 pirate ships and burned about 2,000 houses, but lost a good many men to an ambush during a landing. When the lord of Tsushima sued for peace, the fleet withdrew in early July.
Joseon then combined firmness with conciliation. It opened three ports — Busanpo, Jepo and Yeompo — to Japanese trade, and the Gyehae Treaty of 1443 limited Tsushima to 50 trading ships and 200 seok of rice a year. The growing Japanese communities in the three ports later led to the Revolt of the Three Ports.
