QIANLONG SIX-CHARACTER SEAL MARK IN UNDERGLAZE BLUE AND OF THE PERIOD (1736-1795)

A Ming prototype of this design bearing a Xuande mark and of the period, housed in the Palace Museum, Beijing, published in The Complete Collection of Treasures of the Palace Museum, Blue and White Porcelain with Underglaze-Red (I), Hong Kong, 2000, pp.98, no.92 (fig. 1). Compare with a nearly identical Qianlong mark and period vase in the National Palace Museum, Taipei, illustrated in Blue and White Ware of the Ch'ing Dynasty, Vol II, Hong Kong, 1968, pl.7 (fig. 2).