Disk (<em>bi</em> 璧) with incised glyph and decorated edge

Perforated disk of the type pi [bi] 璧; bored from both sides, leaving rough median ridge; darkly mottled green and golden brown; bluish-gray frosting and veins of incipient disintegration; scattered granular pittings; decoration: lightly incised, a device on obverse, birds, arrows and geometric pattern around outer rim.