Sōma clan

The Sōma clan (相馬氏, Sōma-shi) was a Japanese samurai clan that ruled the northern Hamadōri region of southern Mutsu Province in the Tōhoku region of northern Japan for over 700 years, from the Kamakura period through the Meiji Restoration of 1868. The Sōma claimed descent from the Taira clan via the Chiba clan and took their name from the Chiba clan territories in Sōma District of northern Shimōsa Province. The clan moved its seat from Shimōsa to Mutsu Province in the early Kamakura period, and were confirmed as daimyō of Sōma Nakamura Domain under the Edo-period Tokugawa shogunate.

During the Boshin War of 1868–69, the Sōma clan fought on the side of the Ōuetsu Reppan Dōmei, supporting the Tokugawa regime. After the Meiji Restoration, the head of the Sōma clan became part of the kazoku peerage, with Sōma Aritane receiving the title of shishaku (Viscount).