QIANLONG FOUR-CHARACTER MARK WITHIN A SQUARE AND OF THE PERIOD (1736-1795)

This rare design, reminiscent of the pattern found on 'yuzhi' bowls, compares well to that found on two dishes sold at Sotheby's Hong Kong, 29th November 1978, lot 436 and again at Sotheby's London, 17 December 1996, lots 192 and 193.