Hiraga no Koreyasu

Hiraga no Koreyasu, also called Matsuba no Koreyasu, was the son of Sukemune, founder of the Aki Hiraga clan. In his generation the family settled on its estate in Hiraka district of Dewa Province and took the place name as its family name, styling itself Hiraka, later written Hiraga.

He came of age at the Kamakura mansion of Hojo Yasutoki, the shogunal regent. Yasutoki gave him the character yasu from his own name.