The style and treatment of the decoration follows a group of official imperial ivory seals inscribed Tai Shang Huang Di Zhi Bao, the title assumed by the Emperor Qianlong following his abdication on 9th February 1795. Cf. Soame Jenyns, Chinese Art, The Minor Arts, vol.II, p.168, fig.127, from the Collection of Mr E.H. North, London. A second was sold in London, 15 July 1980, lot 210. Cf. also the Kangxi example sold in London, 7 April 1981, lot 89