Ōuetsu Reppan Dōmei
As a youth, Ōtsuki was employed as an advisor to Sendai Domain, and fought at the Battle of Toba–Fushimi in the Boshin War of the Meiji Restoration on the losing Tokugawa Bakufu side. He later assisted in the formation of the Ōuetsu Reppan Dōmei.