According to "Kocho-Ki" (Records of Kocho era), it has been reported that he was a descendant of Chikasato OOBA who was samurai in Izu Province and given Aoto-so (manor) in Kazusa Province after the Jokyu war.
『弘長記』によれば伊豆の武士で承久の乱で上総国青砥荘を領した大場近郷の子孫と伝えられる。