A mottled jade 'bird' bi disc, Western Han dynasty 西漢 瑞鳥蒲紋玉璧

For a closely related bi disc with similar tones of larger size from the C. F. Wu Collection, see Art of China, January 1988, frontispiece and pl. 28; another of similar design and tone is illustrated in Thomas Fok, The Splendour of Jade: The Songzhutang Collection of Jade, Hong Kong, 2011, pl. 72. A dark green disc with a similar design dated Eastern Zhou or Han dynasty in Jessica Rawson, Chinese Jade: From the Neolithic to the Qing, London, 1995, pl. 15:4. Compare also an example illustrated in Fang Gu, The Complete Collection of Jades Unearthed in China: Shaanxi, vol. 14, Beijing, 2005, p. 130.