酒井氏
The Sakai daimyō clan originated in Mikawa Province. They claim descent from Minamoto no Arichika. Arichika had two sons: one of them, Yasuchika, took the name of Matsudaira; and the other son, Chikauji, took the name of Sakai, and this is the ancestor of the Sakai clan. Sakai Hirochika, the son of Chikauji, had two sons as well; and the descendants of these two sons gave rise to the two principal branches of the clan.