A small irregular circle shaped stone chamber 1 meter in diameter was set up where Ogata bosei naiko kamon-kyo (a large bronze mirror manufactured in Japan with patterns like a flower-petal) with 39.7 centimeters in diameter was placed.
直径1メートルの不正円形の小石室が設けられ、径39.7センチの大型仿製内行花文鏡が納められていた。