Hachiho-ji (Hoshogusou) was excavated from 1989 to 1991 to elucidate the history of the Hachiji shrine. Although it was not possible to clarify the whole picture, relics of the Yayoi period, bricks of the 11th - 13th century, celadon / white porcelain, and southern weapons were excavated. It seems that the establishment of Hachiomiya was probably established around the 13th century.