徳川家重
was the 13th and final "daimyō" of Sōma-Nakamura Domain and the 29th hereditary chieftain of the Sōma clan. He was the younger brother of Sōma Michitane. He had the courtesy title of "Inaba-no-kami" under the Tokugawa shogunate, and his court rank was elevated the Fourth Rank with the "kazoku" peerage title of viscount under the Meiji government. His wife was the daughter of Toda Mitsuhisa of Matsumoto Domain. Toshitane was the second son of Sōma Masutane, and was appointed heir to Michitane in 1858. He was presented in formal audience to "shōgun" Tokugawa Ieshige in March 1865, and became "daimyō" when his brother retired a few months later. During the Bakumatsu period, he initially attempted to remain neutral in the Boshin War, as the domain had negligible military forces. However, after the defeat of the Tokugawa forces at the Battle of Toba–Fushimi in February 1868, he was pressured by his more powerful neighbors (including Iwakitaira Domain and Sendai Domain into joining the Ōuetsu Reppan Dōmei. The Satchō Alliance forced advanced through the Hamadōri region and captured Sōma Nakamura Castle with only token resistance a few months later. Under the new Meiji government, he was appointed Domain governor in June 1868, and was advanced to Fifth Court Rank. In 1871, with the abolition of the han system, he was relieved of his post.