Sō clan

Sō
The emblem (mon) of the Sō clan
Home province	Tsushima Province
Parent house	Koremune clan
Founder	Taira no Tomomune
Founding year	11th century
Ruled until	1871

Sō clan (宗氏, Sō-shi^?) were a Japanese clan claiming descent from Taira Tomomori. The clan governed and held Tsushima Island from the 13th-century through the late 19th-century, from the Kamakura period until the end of the Edo period and the Meiji restoration.

In 1587, Toyotomi Hideyoshi confirmed the clan's possession of Tsushima. In the struggles which followed Hideyoshi's death, the clan sided with the Tokugawa; however, they did not participate in the decisive battles which preceded the establishment of the Tokugawa shogunate. The descendants of tozama Sō Yoshitoshi (1568–1615) remained at Tsushima-Fuchū Domain (100,000 koku) in Tsushima Province until the abolition of the han system . The head of this clan line was ennobled as a "Count" in 1884.

Historians consider the Sō clan to have been an offshoot of the Koremune clan (惟宗氏), who served as local officials of Dazaifu and Tsushima Province. The earliest evidence of Sō clan cohesion arises in the 11th century. The Koremune had their start as governors of Tsushima following an incident in 1246, when the Abiru clan, local district officials (zaichōkanjin) on Tsushima, rebelled against the Chinzei Bugyō and the Dazaifu government which governed all of Kyūshū and the surrounding regions on behalf of the Kamakura shogunate. Dazaifu ordered Koremune Shigehisa to stop the rebellion and to destroy the Abiru clan. He was rewarded for his victory with the post of Jito (local land steward), by the Shōni clan, shugo (governors) of Tsushima.