YONGZHENG IMPRESSED SEAL MARK AND OF THE PERIOD (1723-1735)

Opaque crystalline green glazes, like the ‘eel skin’ glaze on the present vase, which belong to the tea-dust group, seem to have their origins in the Tang dynasty at kilns making black wares, but reached their peak of popularity on imperial porcelains of the 18th century. Their unique appearance is due to slight under firing of a glaze with significant iron and magnesium oxide content, which results in the development of fine pyroxene crystals during cooling. These give the glaze the attractive brown, greenish or yellowish micro-crystalline appearance, which was so prized at the Qing court. The perfection of this glaze on porcelain seems to have been achieved in the Yongzheng reign, when the imperial kilns were at pains to produce elegant new glazes for the emperor's appreciation. These glazes are sometimes called Changguan you or 'Imperial Factory glazes' in Chinese, and indeed they are mentioned in Tang Ying's famous Taocheng jishi bei ji (Commemorative Stele on Ceramic Production) of 1735, where three types are noted - eel-skin yellow, snake-skin green, and spotted yellow. In particular, the Emperors Yongzheng and Qianlong seem to have admired the 'antique' quality that these tea-dust and eel-skin glazes imparted to the porcelains on which they were used.

Yongzheng-period ‘eel skin’ glazed vases of this size are somewhat unusual, perhaps because of the difficulty in firing the glaze to perfection. A smaller (27.9 cm.) vase with 'eel skin' glaze modeled after a bronze form was sold in Important Chinese Art Including Jades from the De An Tang Collection and Gardens of Pleasure – Erotic Art from the Bertholet Collection, was sold at Sotheby’s Hong Kong, 29 April 2022, lot 3614. The more standard, smaller (18.4 cm. high) shape found with the ‘eel skin’ glaze is the bottle form with bulbous lower section, such as an example with an impressed Qianlong seal mark sold at Christie’s Hong Kong, 28 November 2012, lot 2314.