Prototypes of this form and design are known. A pair of bowls of this pattern with Yongzheng marks was included in the exhibition, Ch'ing Porcelain from the Wah Kwong Collection, Hong Kong, 1973, no. 59, and another is illustrated in the Powell-Cotton Collection of Chinese Ceramics, Powell-Cotton Museum, Birchington, Kent, 1988, no. 87. A Qianlong bowl of this pattern in the Ohlmer Collection, Roemer Museum, Hildesheim, is illustrated by U. Wiesner in Chinesisches Porzellan, Mainz am Rhein, 1981, no. 47. A pair of similar Jiaqing marked bowls was sold in our Hong Kong rooms, 1 June 2011, lot 3924.