Asonuma Tomotsuna

Asonuma Tomotsuna was lord of the Tōno Asonuma, a warrior house of Fujiwara-descended Ashikaga stock, seated at Yokota Castle in Hei district, Mutsu province. In 1334 his title to the Tōno estate was confirmed by Kitabatake Akiie, the Southern Court's governor of Mutsu.

His second son Jirō went to Ōtsuchi to keep order on the eastern coast of Hei district and built Ōtsuchi Castle as his seat, becoming the founder of the Ōtsuchi house.