upon themselves to repair relations with Korea, sending a number of envoys under the guise of being official shogunal envoys. In doing this, the clan sought to improve their position with both the shogunate and Korea. There is evidence that they altered official documents from both to make themselves look better to the other The Sō did not participate in the Battle of Sekigahara in 1600. The tozama Sō clan were allowed to continue to rule Tsushima. Tsushima and the area around Tashiro in Hizen Province were included in the clan's fief (han), rated as worth 100,000 koku for its diplomatic and economic importance, though its agricultural production was actually under 30,000 koku per year. After the clan managed to resume diplomatic relations with Korea, the Tokugawa shogunate entrusted it with diplomatic negotiations and trade with Joseon. After the abolition of the han system in 1871, the last known head of the clan, Sō Shigemasa (Yoshiaki), was made Governor of Izuhara Prefecture (Tsushima, renamed). Clan lords Sō Shigehisa (重尚)(1245–1262) - fought against the Abiru/Ahiru clan (阿比留在庁) and became Governor of Tsushima Sō Sukekuni (助國) (1262–1274) - fought Mongolian invasion force and died in 1274 Sō Moriakira (盛明) (1274–1302) Sō Morikuni (盛國) (1302–1349) Sō Tsuneshige(經茂) (1349–1366) Sō Sumishige (澄茂) (1366–1370) Sō Yorishige (頼茂) (1370–1402) Sō Sadashige (貞茂) (1402–1419) Sō Sadamori (貞盛) (1419–1452) - fought the Korean army led by Yi Jong Mu during the Oei Invasion and entered into relations with the Joseon Dynasty Sō Shigemoto (成職) (1452–1468) - granted "Governor of Tsushima" title by the Joseon Court in 1461. Sō Sadakuni (貞國) (1468–1492) Sō Kimori (材盛) (1492–1505) Sō Yoshimori (義盛) (1505–1520) - The Sō Clan supported a Japanese traders' uprising, against Joseon's policies, known as "Three-Ports incident". Sō Morinaga (盛長) (1520–1526) Sō Masamori (将盛) (1526–1539) Sō Haruyasu (晴康) (1539–1553) Sō Yoshishige (義調) (1553–1566) Sō Shigehisa (茂尚) (1566–1569) Sō Yoshizumi (義純) (1569–1579) So Terukage (昭景)(1579–1589) - he submitted himself to Toyotomi Hideyoshi in 1587. So Yoshishige (義調) (1589–1592) Sō Yoshitoshi (義智) (1592–1615) - he was a daimyō under the commander of Konishi Yukinaga during the Imjin War (1592–1598). Sō Yoshinari (義成) (1615–1657) Sō Yoshizane (義真) (1657–1692) Sō Yoshitsugu (義倫) (1692–1694) Sō Yoshimichi (義方) (1694–1718) Sō Yoshinobu (義誠) (1718–1730) Sō Michihiro (方熙) (1730–1732) Sō Yoshiyuki (義如) (1732–1752) Sō Yoshishige (義蕃) (1752–1762) Sō Yoshinaga (義暢) (1762–1778) Sō Yoshikatsu (義功) (1778–1785) Sō Yoshikatsu (義功) (1785–1812) Sō Yoshitada (義質) (1812–1838) Sō Yoshiaya (義章) (1838–1842) Sō