The Hirayama clan was a family belonging to the west party of Musashi Province, with its ancestor Muneyori HIMATSURI, who was assigned to present Musashifuchu City (Tokyo Prefecture), from Kyoto as Kokushi (provincial governor).
平山氏は日奉宗頼を始祖とする武蔵国西党の一族であり、宗頼は京都から武蔵府中市_(東京都)に国司として赴任。