This rare and exquisite jar reflects both the exceptional quality of porcelains made for the Yongle emperor, and the successful innovation that was undertaken at the Imperial kilns during his reign. It was in this period, in the first quarter of the 15th century, that skilled ceramic craftsmen experimented with a range of different glazes and decorative techniques, achieving results that would inspire potters for centuries. Among the experiments was the development of glazes, which looked back to classic Song dynasty wares, but which were reformulated for use on pure white porcelain.
As early as the Tang dynasty (618-907) celadon-green glazes were refined to the extent that they appealed to the court and to scholars. Lauded by poets, these Yue wares were among the first ceramics to be appreciated for their own beauty, as opposed to being less expensive substitutes for other materials. Celadons developed further in the Song dynasty (960-1279), establishing a special place among court ceramics. It is little wonder that the early 15th century potters working at the Imperial kilns should seek to develop an even more refined celadon glaze. However, the early celadon glazes were applied to stoneware bodies, which were grey in tone, and the overall effect was usually quite muted. In the early Ming dynasty the potters at the Imperial kilns at Jingdezhen were working with a highly refined, pure white porcelain body, which required a different type of celadon glaze. While the blue-green color of the new glaze still owed its color to small amounts of reduced iron, the clarity of tone and the purity of color gave this Yongle glaze, as seen on this jar, a much greater delicacy. Perhaps even more than the mise Yue wares, to which he was referring, the late Tang poet Xu Yin's description "like a full moon dyed with spring water" would be appropriate for this glaze.
Few Yongle porcelains with this delicate, clear, bluish-green glaze have survived. There are, however, two Yongle jars of the same form, and with the same glaze in the palace collections. These are of different sizes. The jar in the Palace Museum, Beijing, which measures 14.1 cm. across its base is illustrated in The Complete Collection of Treasures of the Palace Museum - 37 - Monochrome Porcelain, Hong Kong, 1999, p. 134-5, no. 123, where the glaze color is described as cuiqing, bluish-green or jade green. (Fig. 1) The example from the National Palace Museum, Taipei, which measures 12.3 cm., is illustrated in Porcelain of the National Palace Museum, Monochrome Ware of the Ming, Book I, Hong Kong, 1968, p. 50, pls. 10, 10a and 10b, where the color of the glaze is described as dongqing, 'winter green'. Interestingly, these latter jars have three loop handles rising from a quatrefoil base on the shoulder. The current jar would also have had similar handles, but we may assume that at sometime in the jar's history one or more of the handles was broken. However, three flower heads have been carved from the remaining porcelain on the shoulder. It must have required considerable skill on the part of the craftsman who undertook this work, since carving fired porcelain without damaging the surrounding glaze would have been very challenging. The fact that such work was commissioned indicates the high regard in which the jar was held by its owner.
A small number of additional surviving Yongle porcelain vessels have pale celadon glazes. There are, for example, both a stem cup and a bowl in the collection of the Palace Museum, which have fine glazes, and are illustrated in The Complete Collection of Treasures of the Palace Museum - 37 - Monochrome Porcelain, op. cit., pp. 136-7, nos. 124 and 125, but neither quite attains the perfection of glaze color and clarity seen on the current vessel and the two other jars.
A Yongle jar of the same form as the current vessel, but with three handles remaining on the shoulders, and a tianbai, 'sweet white' over incised anhua, 'secret decoration', was illustrated by B. Gyllensvärd, when the jar was in the Carl Kempe Collection, Chinese Ceramics in the Carl Kempe Collection, Stockholm, 1964, p. 198, no. 664. A jar of similar shape and color to the current jar, but without handles or traces of handles, was sold, Sotheby's, Hong Kong, 8 October 2009, lot 1624. On the current jar, the unglazed white flowers on the shoulders enhance the delicacy of the vessel, and complement the refined pale celadon glaze.