A flat jade disc with a small hole in the center, made in ancient China for ceremonial purposes, possibly symbolizing Heaven. Bi disks have also been described in ancient Chinese texts as a symbol of rank. Jade disks and disklike axes have been found in 4th- and 3rd-millennium BC graves at east-coast Neolithic sites such as Beiyinyangying. Polished stone disk segments are known still earlier at Banpo.