The brilliant, jewel-like sapphire-blue glaze on this vase serves to emphasize the elegance of the form and the generosity of the proportions of the vessel. The rich cobalt-blue glaze is sometimes referred to as 'sacrificial blue', deriving from the use of vessels bearing this color glaze during sacrifices at the Imperial Temple of Heaven. In 1369 the first Ming dynasty emperor Hongwu issued an edict declaring that the vessels used on the Imperial altars should henceforth be made of porcelain. Each temples was associated with a specific color of porcelain, and in addition to blue being used in the Temple of Heaven, red was used in the Temple of the Sun, yellow in the Temple of Earth, and white in the Temple of the Moon. During the Qing dynasty, however, these massive monochrome vases were made as part of decorative furnishings for the Palace.
The potters at the Imperial kilns in the eighteenth century were highly skilled and the technology used to produce porcelains was highly developed. By the eighteenth century, refining techniques were also quite sophisticated and the additional elements in the cobalt ore to be used in coloring rich cobalt-blue glazes, like the glaze on the present vase, could largely be controlled. Elements such as iron and manganese, for example, had considerable effect on the color of the fired glaze. In addition, pigments that were high in alumina tended to develop cobalt aluminates in firing, resulting in cooler blue tones, while pigments which contained more silica produced cobalt silicates, resulting in warmer, more purplish, blues.
It is rare to find a cobalt blue-glazed vase of this form and of such large size with a Yongzheng mark. Another rare example of similar size from the Xulong Collection was exhibited at the Zhejiang Museum and published in A Collection of Porcelain, Beijing, 2006, pp. 118-119. A larger vase of slightly different proportions, also bearing a Yongzheng seal mark, was sold at Sotheby's Hong Kong, 20 November 1984, lot 486, entered the Wang Xing Lou Collection, and is illustrated in Imperial Perfection - The Palace Porcelain of Three Chinese Emperors, Hong Kong, 2004, pp. 224-225, no. 87. More recently, a smaller (13 in.) cobalt-blue-glazed bottle vase with Yongzheng mark from the E.T. Chow Collection was sold at Sotheby’s Hong Kong, 3 April 2019, lot 3658.
Monochrome blue-glazed vases of this shape and glaze are more commonly found with Qianlong marks. One was included in the exhibition The Wonders of the Potter's Palette, Hong Kong, 1984, no. 85. Another example of slightly different shape is in the Baur Collection, Geneva, illustrated by J. Ayers and M. Sato in Sekai Toji Zenshu, Volume 15, Qing Dynasty, Tokyo, 1983, p. 199, no. 272. A third example from the Nanjing Museum Collection was included in the exhibition, Qing Imperial Porcelain, Hong Kong, 1995, and illustrated in the Catalogue, no. 66.