A RARE CHINESE IMPERIAL BLUE-GROUND ZHADOUSIX CHARACTER YONGZHENG MARK AND OF THE PERIOD 1723-35With a wide flared rim, decorated with an even dark blue glaze, the interior white, all raised on a short flared foot, 12.5cm.Provenance: from the collection of Professor J Norman Collie, FRS (1859-1942) and thence by descent.Cf. The Complete Collection of Treasures of the Palace Museum, Monochrome Porcelain, p.81, no.74 for another example of a blue-ground zhadou also from the Yongzheng period.