66 mm，69 g
A collection of 11 astronomical instruments and sun watches
A rare pre-Christian Chinese Pi disc from jade, 66 mm, 69 g
A bi is a flat Jade disc with a circular hole in the centre which was used for ceremonial purposes in ancient China. Their usual size is between 25-30 cm, but discs of only 1 cm as well as some as large as 50 cm have been found. In old Chinese texts the bi are described as symbols of rank and were used as ritual artefacts during the Neolithic Liangzhu period (3300-2300 B.C.) . Most bi were found together with cong tubes in the tombs of high-ranking people. Is is assumed that these objects symbolise heaven and earth, but the exact significance of these artefacts varies from dynasty to dynasty and only a few details are truly known today. So the bi were left in the tombs to show the deceased the way to heaven, but the privilege remained reserved to the highborn. According to other sources the bi were also for example handed over to the winner after a fight.
In later periods bi were often misinterpreted as sundials.