The Yamaoka clan was the powerful retainer of the Shugo (provincial military governor) Rokkaku clan and was in charge of the military affairs of the Rokkaku army together with the Aochi clan and other clans.
山岡氏は守護六角氏の有力家臣で、青地氏らとともに六角軍の軍事の中枢を担っていた。