James C. Y. Watt, 'Neolithic Jade Carving in China' in TOCS 53 (1988-1989), pp.11-26, pl. 17, 17 a.
Teng Shu-p'ing, 'Mysterious Symbols on Neolithic Chinese Jade' in National Palace Museum Research Quarterly, vol.10 nr.3, Spring 1993.
for discussion on neolithic jades with patterns
Ming Wilson, 'Liangzhu Jades Rediscovered' in Oriental Art, Winter 1995/96, pp.2-8.
Ming Wilson, Chinese Jades, 2004, no.3
Purchased with the assistance of The Art Fund, the Vallentin Bequest, Sir Percival David and the Universities China Committee
ca. 2500 BC (made)
Liangzhu disc (bi) with bird pattern, Nephrite jade, circa 2500 BC
Diameter: 32.5 cm whole piece, Diameter: 3.8 cm hole, Thickness: 1.5 cm
John Ayers and Jessica Rawson, Chinese Jade throughout the Ages (Victoria & Albert Museum 01/01/1975-31/12/1975)
China, room 44
About 2500 BC
Round discs with a central hole are found in many graves. Their significance in prehistorical China is not clear but they may have been ritual objects.
Carved nephrite jade
Liangzhu culture, south China
Museum no. A.42-1936 
Variegated dark green and brown. Pattern consists of four groups of spirals, four in each group. Between every alternate group of spirals is a small bird with spread wings and short bifurcated tail flying in clockwise direction. One of the birds is clearly discernible but the other one is obscured by encrustations on the stone. Each spiral measures a regular 5cm, and the space between each group is evenly laid out - an indication that the pattern was very carefully executed. No ridge in the hole.
An important piece for its size and pattern. It is slightly larger than the bi in the Freer Gallery with similar pattern (nr.17.79) which measures 31.8cm. The pattern is found along the slightly concave outer rims, made up of short, repeated incised lines.
James Watt opinon 11/6/1987: Neolithic, one of the largest known. N.B. Carved fret pattern and single bird round the outside edge; this is only third with decoration, two more are in the Freer Gallery. Stone is typical of jade from Liangzhu culture, comes from near Shanghai; impure, contains bits of nephrite.
Thomas Lawton opinion 11/7/90: Concave surface of outer rim is typical, variegated nature of stone also.
A ‘bi’ is a flat circular slab of jade with a central hole. An ancient Chinese text entitled the ‘Zhouli’ (‘Rituals of Zhou’) describes the ‘bi’ as a ceremonial object to sacrifice to Heaven. However the ‘bi’ was made at least a thousand years before the ‘Zhouli’ was written. Its function in prehistoric times remains unknown.