This Ming jar has a beautiful blue Jun glaze. Careful control of the firing has enabled the potter to achieve the attractive opalescence that has traditionally been admired in blue Jun glazes. This jar is an important link between Yuan dynasty Jun ware jars, like that excavated from a tomb near Datong in 1958, and now in the collection of Datong City Museum, Shanxi Province, illustrated in Zhongguo taoci quanji, Junyao, Shanghai renmin meishu chubanshe Bi-no-bi, Shanghai/Tokyo, 1983, no. 54, and Qing dynasty vessels with imitation Jun ware glazes produced at several kilns, including Guangdong and Yixing.
These latter kilns were not able to produce a true Jun glaze, which relied on complex optical effects within the glaze structure to obtain the opalescent blue colour. These required precise control of temperature and length of firing, as well as a long cooling time, in order to achieve the desired glaze colour and translucency. When the Qing potters copied Jun glazes at the Yixing, Guangdong or even Jingdezhen kilns, they usually had to add cobalt to the glaze mixture in order to obtain the blue colour. The beautiful colour of the current jar has been achieved without recourse to such additions, showing that it is a direct continuation of the classic Jun tradition.