Note: The mottled glaze on this vase was first developed in the Yongzheng reign by the talented Superintendent of the imperial kilns in Jingdezhen, Tang Ying (1682-1756). In order to recreate the celebrated Jun glazes of the Song and Ming dynasties, Tang sent his trusted assistant to the Jun region in Henan province to learn from the local potters. Among the many types of glazes derived from those efforts are mottled purple ones, such as the flambé variety, and mottled turquoise ones such as 'robin's egg', which Tang Ying termed lu Jun or Oven Jun. This glaze is mentioned in Tang’s Taocheng jishi bei ji (Commemorative stele on ceramic production) from 1735. The colour of 'Robin's Egg' glaze is described as intermediate between the glazes of the Shiwan kilns of Foshan, Guangdong province, and those used by the Yixing kilns in Jiangsu province, but having a more beautiful mottled effect.