YONGZHENG SIX-CHARACTER MARK IN UNDERGLAZE BLUE WITHIN A DOUBLE CIRCLE AND OF THE PERIOD (1723-1735)

A dish with the same motif and also painted in the Ming style, but of slightly smaller size (27.8 cm.), is illustrated in Treasures in the Royalty: The Official Kiln Porcelain of the Chinese Qing Dynasty, Shanghai, 2003, p. 122.
Compare, also, another Yongzheng-marked dish sold at Christie's New York, 1 June 1990, lot 248.