The fine white glaze of the Chenghua reign is perhaps the most successful in imitating white jade. It is assumed by many scholars that the famous tianbai sweet white glaze, first seen in the reign of the Yongle Emperor, was inspired by jade, which was a material particularly admired by Yongle. Indeed, excavations of the Yongle strata at the Imperial kiln site comprised well over 90 white porcelains. The tianbai glaze was prized for its soft unctuous feel, and the way that light travelled through it. However, further developments took place in the making of imperial white porcelains in the Chenghua reign (1465-87) achieving, as can be seen from the current bowl, an even greater purity of color and unctuousness of glaze. Compared to earlier glazes, the Chenghua glaze has been described as: ...more softly luminous and more jade-like in appearance (see The Tsui Museum of Art, A Legacy of Chenghua - Imperial Porcelain of the Chenghua Reign Excavated from Zhushan, Jingdezhen, Hong Kong, 1993, p. 72).
The particular whiteness of the Chenghua porcelain was achieved by very careful preparation of the raw materials, resulting in minimal levels of iron oxide, which would have discolored the glaze, and slightly higher levels of aluminium oxide, allowing firing at a slightly higher temperature, which resulted in a denser and whiter body. Recent scientific analysis has shown that the porcelains of the Chenghua reign contain less iron oxide than any of their predecessors. The very white Chenghua body material is complemented by a glaze, which also contained very little iron oxide, as well as less calcium oxide, resulting in a clearer glaze with a finer texture. This jade-like texture is enhanced by the very small, evenly and densely dispersed bubbles in the glaze, which give a softer, smoother appearance when reflecting light. The current bowl is also very finely potted, which enhances its translucency.
Although a number of Chenghua white cups are known, and a significant number of sherds of white cups were found in the later Chenghua stratum at the Imperial kiln site at Jingdezhen (see The Tsui Museum of Art, A Legacy of Chenghua - Imperial Porcelain of the Chenghua Reign Excavated from Zhushan, Jingdezhen, op. cit., p. 66, pl. 14b), very few bowls have survived. Thus, the current bowl is very rare. An example of a very similar Chenghua white bowl may be found, however, in the collection of the National Palace Museum, Taipei, and is illustrated in Catalogue of the Special Exhibition of Cheng-hua Porcelain Ware, Taipei, 2003, pl. 104. (Fig.1).
Pure white bowls of this type would have been suitable for ritual use. White was an appropriate color for Buddhist ritual, and was also the color designated for the Xiyuetan, the Altar of the Moon, as well as for offerings made at the altar to the Imperial Ancestors. In considering why so few white bowls have survived, compared to the number of white cups, one is lead to the conclusion that fewer were made. It seems probable that these white Imperial Chenghua bowls were reserved for ritual purposes, but may not have been in daily use, hence their rarity.