Asonuma

The Asonuma were a warrior family whose Tōno branch held lands in Mutsu Province. Asonuma Hirotsuna gained the stewardship of Tōno after the Ōshū campaign of 1189, and his descendants ruled from Yokota Castle. In 1334 Kitabatake Akiie confirmed Asonuma Tomotsuna's possession of Tōno.

The family came under Nanbu authority after failing to join Toyotomi Hideyoshi's Odawara campaign in 1590. In 1600, while Asonuma Hironaga was away on campaign, relatives seized his castle; he failed to recover Tōno and died in exile in Date territory.