Kasai

The Kasai were a warrior house of the Chichibu Taira line, founded by Kasai Kiyoshige, son of Toshima Kiyomoto, whose family held the Kasai shrine-estate in Shimōsa. Kiyoshige and his father joined Minamoto no Yoritomo's rising against the Taira in 1180. After the Northern Fujiwara were destroyed in 1189, Kiyoshige received wide lands in Mutsu and built his seat at Hiyoriyama in Ishinomaki.

The clan moved its headquarters to Teraike and emerged during the Nanboku-chō wars as a major regional power. In the Sengoku age it ruled several districts of central Mutsu.

Kasai Harunobu failed to join Toyotomi Hideyoshi's Odawara campaign in 1590 and was attainted. With his death in 1597 the house ceased to be daimyō, though a surviving line later served the Tokugawa as hereditary sewer cleaners of Edo Castle.