Japan–Korea Diplomacy

Timeline

1. 1551–1555Tsushima Island · Tsushima IslandJoseon used the So clan as its diplomatic channel to Japan; the So held the title 'Joseon-tongguksa' (envoy to Korea), relaying state letters and arranging receptions. Though Japan was divided in the 1550s, daimyo in Kyushu and the Kinai still maintained contact with Joseon through the So, continuing the exchange framework of the Muromachi period.
2. 1555–1560Busan Wae trading post · BusanJoseon established a Wae trading post at Busan, confining Japanese merchants to trade there; annual gift ships sailed regularly to Japan carrying silk, books, and medicines, returning with sulfur, copper, blades, and ceramics. Envoy exchanges continued throughout the 1550s, with both sides confirming investiture relations through state letters and also negotiating issues such as wakō pirates and castaways.
3. 1558–1560Kyushu, Japan · KyushuAs the fortunes of Japan's Sengoku daimyo rose and fell, competition among powers like Ōtomo and Shimazu over Japan–Korea trade interests intensified. Joseon closely watched Japanese political changes, gathering intelligence ahead of Toyotomi Hideyoshi's rise and pre-Imjin War diplomatic assessments. Diplomacy in this phase was largely peaceful, but latent risks were already emerging.