According to documents such as the "Shito Gobusho" (a five-volume apologia of Shinto), the word 'Hachiyo' is written on the mirror that was enshrined in the Inner Shrine of Ise.
伊勢神宮の内宮に奉安されている鏡は、神道五部書等によれば「八葉」と書かれている。