This is the largest Jade(Nephrite) Bi in collection of Liangzhu Culture Jades. The dia:37.0cm(14 1/2") is among the top ten largest in worldwide public collections. More important is the beautiful greenish uniform texture when light is shine through it. Always is asked,what it was used for,but since it is in the prehistorical period any answer is just an opinion. Saying that, it is mentioned in the Book of Rites in the Han Dynasty that the BI is to worship Heaven and the CONG is to worship the Earth, but that book is a lapse of 2000 years after Bi and Cong was first produced in 2000 B.C.!!! Posted this as it complements the CONG that was recently also added.

Visit Friends of Jade website - several excellent articles on fake and real Liangzhu and also the best  'faker' currently around and the price is not cheap. Look it up in the archives.