One of the outstanding achievements of the potters at the Imperial kilns, after their restoration in the early years of the Kangxi reign, was the introduction of new kinds of glaze colors, incorporating new technology and new minerals. This rich ruby enamel is one of these innovations. These new enamels included an opacifier to give previously translucent glazes an opaque body. A similar ruby enamel can be seen on a bowl of smaller size and different shape included in An Exhibition of Important Chinese Ceramics from the Robert Chang Collection, Christie's, London, June 1993, no. 40.
For a bowl of this rare shape see the Yongzheng-marked example of smaller size (14 cm. diam.), covered on the exterior with a yellowish-green enamel, illustrated by J. Ayers, The Baur Collection Geneva, Chinese Ceramics, vol. III, Geneva, 1972, no. A 501. See, also, a bowl of the same shape and size as the present bowl in pink enamel sold at Sotheby's, London, 13 November 2002, lot 147.