Underglaze red refers to porcelain decorated with copper-red pigment designs on the body, covered with a transparent glaze, and fired in a high-temperature reducing atmosphere, resulting in red patterns beneath the glaze. Underglaze red porcelain from the Xuande period of the Ming Dynasty and the Kangxi and Yongzheng periods of the Qing Dynasty holds great historical renown, but their achievements were built upon the foundation laid during the Yuan Dynasty.
Underglaze red was one of the important innovations by the porcelain artisans of Jingdezhen during the Yuan Dynasty, sharing a production process largely similar to that of Yuan blue-and-white porcelain. Both are underglaze decorations, differing only in their red and blue hues. Both involve painting designs on the body with a brush, but they use different materials—copper for red and cobalt for blue. Both require high-temperature firing, but their atmospheric demands differ. Underglaze red imposes strict requirements on the kiln atmosphere, as copper only turns red in a reducing flame, whereas blue-and-white is more tolerant of kiln atmosphere variations, with little impact on the cobalt’s blue hue. As a result, blue-and-white porcelain was easier to fire, and a relatively large number of Yuan blue-and-white pieces have been excavated or preserved as heirlooms.
Due to the difficulty of firing, underglaze red had an even lower production yield, and few Yuan underglaze red pieces have survived or been unearthed. Particularly rare are scientifically significant excavated examples. Overseas, only a batch of Yuan underglaze red porcelain has been discovered in the Philippines. Domestically, examples include an underglaze red Yuhuchun vase unearthed in Fengtai, Beijing; a pair of blue-and-white underglaze red lidded jars from the Baoding hoard; and a small number of fragments from the Yuan capital Dadu and the Hutian kiln site in Jingdezhen. Additionally, the Wu County Museum in Jiangsu Province houses an underglaze red lidded jar decorated with dragon patterns. The jar’s body is carved with three sets of designs, and the belly features a vibrant red underglaze ground that contrasts with a white dragon—an exceptionally rare masterpiece.
