In addition to the common wucai palette of red, green, yellow, purple, brown, and turquoise, another noteworthy color in Chongzhen wucai is blue - a hue that merits further discussion and study. A few representative examples can be cited based on existing publications and extant pieces: The “Blue Enamel Dish with Mandarin Ducks” from the Butler Family Collection in the UK (published in Seventeenth Century Chinese Porcelain from the Butler Family Collection), The “Wucai Dish with Two Tigers” in the Sidney Moss Collection, London (Fig. 24), The “Wucai Dish with Insects” (Fig. 25) and “Wucai Lobed Dish with Twin Rabbits in Relief” (Fig. 26), both in the Yanshan Art Museum.
Upon close examination, the “Wucai Dish with Tigers” and the “Wucai Dish with Insects” appear to be part of the same series, characterized by the use of yellow, green, purple, turquoise, and, notably, blue enamel. These two pieces stand out not only for incorporating the exceptionally rare blue enamel but also for their lack of red, resulting in a color scheme reminiscent of sancai (three-color ware). This restrained palette creates a refined, understated visual effect, which is particularly unusual in late Ming wucai.
The blue enamel used in these pieces is derived from cobalt oxide. However, natural cobalt ores in the Ming period often contained impurities such as manganese, copper, and iron. Without advanced refining processes, these mixed metal compounds produced a blue that was less saturated and more muted than the deep, intense cobalt blue seen in later periods. This distinctive blue enamel, with its slightly softer tone, contributes to the unique aesthetic character of Chongzhen wucai.
A close examination of the blue enamel in the aforementioned five examples reveals that most of the blue tones are closer to turquoise or peacock blue, a shade obtained by adding cobalt to the base of peacock green. Both turquoise and peacock green originate from the lead-potash glaze technology of the Yuan dynasty, particularly from the northern fahua wares.
(Peacock green and peacock blue are often confused and generally both referred to as turquoise. However, they differ in chemical composition, resulting in distinct colors. Peacock Green (孔雀绿): Primarily a copper-based enamel. The green hue is achieved through the use of copper oxide as the main colorant in a lead-based glaze. Peacock Blue (孔雀蓝): A cobalt-based enamel. Cobalt oxide serves as the main colorant, but the presence of copper can alter the shade toward a bluish-green.)
The use of peacock green and turquoise in overglaze enamels at Jingdezhen began in the Hongzhi period and became especially popular during the Jiajing and Wanli reigns. However, the depth and purity of blue seen in these Chongzhen-period examples have no precedents in earlier wares.
A particularly noteworthy instance is the blue coloration on the body of the rabbits in the “Wucai Lobed Dish with Twin Rabbits in Relief” (Fig. 26). The blue on the rabbits is noticeably more intense and purer than the turquoise seen on other pieces. This stark difference suggests a higher cobalt content in the pigment.
To confirm this observation, an X-ray fluorescence (XRF) spectrometric analysis was conducted on the blue enamel of the rabbits. The results indicate that the base glaze consists mainly of silica and lead, with cobalt as the sole colorant. This finding aligns with the visual assessment, highlighting the unusually high cobalt purity in the blue enamel - a significant technical advancement during the Chongzhen period.
For a long period during the Ming dynasty, low-temperature overglaze decoration at Jingdezhen lacked blue enamel, a deficiency closely related to the limitations in cobalt ore refining techniques. The emergence of several blue-enamelled pieces from the late Ming period, as exemplified by the aforementioned examples, marks a pivotal moment in the development of overglaze blue at Jingdezhen.
Sample analyses further reveal the separation of high-purity blue enamel from the previously mixed turquoise blue, highlighting the significant advancements in cobalt ore refinement achieved by late Ming artisans. This technical breakthrough laid the groundwork for the widespread use of blue enamel in the Qing dynasty.
The overall development of wucai during the late Ming period can be described as a phenomenon that thrived abroad while receiving relatively little domestic attention. Japan, in particular, was a key market for Jingdezhen’s finest wucai, with numerous masterful pieces commissioned specifically for export. These exquisite works help fill a critical gap in the historical narrative of Jingdezhen wucai, serving as a vital link between Ming and Qing ceramic production.
After three centuries of evolution, wucai reached its peak in just three short decades during the late Ming period, ultimately achieving a level of technical and artistic maturity that would become a defining chapter in the legacy of Chinese polychrome porcelain.
This blog article series is based on a paper written by Mr. Li Yanxun of the Yanshan Art Museum in Jingdezhen for the 2018 special exhibition Eastern Brilliance: Special Exhibition of Japanese-Commissioned Porcelain from Late Ming China, organized by the Tang Ying Society. The paper was published in the exhibition catalogue released in 2021.