A large jade disc, bi, Mid-Warring States Period-Han Dynasty, 4th century B.C.-3rd century A.D. Carved on both sides with raised bosses in the form of comma spirals enclosing the central aperture within raised borders. The stone of yellowish celadon tone with brown and opaque white inclusions. ', 15.6 cm diameter. Provenance: collection of the jade expert Zeng Tujin, acquired in the 90s.