The "Bi" disc (also called "pi" disc) was a kind of circular jade artifact, dating from the Ancient China. The first bi discs were manufactured during the Neolithic period, more precisely under Liangzhu’s culture (3400-2250 BC). Some late samples were dated from the Shan, Zhou and Han dynasties. Some of these discs were also made of glass.
Most of the time, the bi disc looks like a jade plate with a centered hole. The bi discs of the Neolithic period were not decorated, but the following ones, such as Zhou dynasties’, were adorned with relief sculptures which patterns represented the celestial divinities, as well as some qualities and powers that the carrier of the disc would like to invoke or incarnate. Some objects, laboriously manufactured, showed the focusing of the power and abilities of a few elite groups.
Later on, the traditions associated the "bi" to the heaven and the "cong" (tubular shaped) to the earth. Afterwards, more and more bi discs came out, with images reflecting the earth and heaven; the circular shape of the disc may also have a symbolic or esoteric connotation as can be linked to the astronomic knowledge of that period. These objects were handled by Shamans who were spiritual leaders of the Liangzhu society and they were also the transmitters of cosmologic knowledge.
As a matter of fact, the original signification of the "bi" is unknown as the Neolithic civilization had not left any written story. Long time ago, the bi disc was also buried with the dead, because it was assumed that this celestial symbol will accompany him to the after-life or the "heaven", and a "cong" was connecting the body to the earth. These objects were placed according to the rituals inside the tomb, just above the corpse of the eminent and distinguished persons.
In other words, the jade was used throughout the Chinese history for demonstrating the integrity of a person as well as his or her social ranking. Nowadays, the jade "bi" discs are used as amulet, jewelry or decorating material.