Turquoise-enameled bowls of this shape and size with Yongzheng mark are illustrated by J. Ayers, The Baur Collection Geneva, Chinese Ceramics, vol. III, Geneva, 1972, no. A 478; by S. Valenstein, A Handbook of Chinese Ceramics, The Metropolitan Museum of Art, New York, 1989 (rev. ed.), p. 252, no. 257; in the Zhuyuetang Collection, Shimmering Colours: Monochromes of the Yuan to Qing Periods, Art Museum, The Chinese University of Hong Kong, 2005, p. 179, no. 106; in Chinese Ceramics from the Hakuto-ro Collection, The Museum of Oriental Ceramics, Osaka, 2003, p. 38, no. 100; one included in the exhibition, Imperial Porcelain of Kangxi, Yongzheng & Qianlong, S. Marchant & Son, June 1996, no. 19, where this particular form is called a Yongzheng invention. See, also, the pair sold in our Hong Kong rooms, 1 November 1994, and a single bowl also sold in our Hong Kong rooms, 30 April 2000, lot 594.