Sō clan
The Sō clan was one of few "daimyō" clans during the Edo period which continued to control the same fiefs it controlled previously. Although it fought against Tokugawa Ieyasu at the battle of Sekigahara, the Sō clan was allowed by the shogunate to continue to rule Tsushima and entrusted it to diplomatic negotiations and trade with Joseon Korea. Its services included receptions of Korean missions to Japan. The Fuchū domain sold imports and bought exports in Osaka and Kyoto. It negotiated trade and diplomacy with the Nagasaki Commissioner in Nagasaki. It had an office in Busan where daily trade and diplomatic service were conducted.