The Ando clan as from Tadasue's generation, was engaged in the management of Ezogashima under the name of Hiyama Yakata, while constructing the Hiyama-jo Castle and temples.
忠季以降の安東氏は、檜山築城や寺院建立を行う一方で蝦夷島の経営にも努め檜山屋形と称した。