Lot Essay
Compare the plain bi of larger size (32.1 cm. diam.) with similar small central aperture and opaque ivory-coloured alteration at the outer edge, Qijia culture, found at Houliugoucun, Jingning, Gansu province, illustrated in The Complete Collection of Jades Unearthed in China, vol. 15, Beijing, 2005, p. 5 (fig. 1).