Rehuo (惹火) and Yaobian (窑变)

In this chapter we turn to a partial flaw, now an accepted and occasionally desired flaw; Yixing teapots with kiln marks, including uneven coloration, deposits of ash, and the formation of glaze, were originally considered flawed and called yaobian (窑变, “kiln transmutation”)[1] and later rehuo (惹火, “fire provoked”). As a flaw linked to kiln firing, yaobian predates the development of zisha teapots in Yixing and exists as either a flaw or desirable property in other ceramic arts of China. While the term yaobian was in regular use for glazed wares colored by natural variations in kiln-atmosphere as early as the 1300s CE (predating the term rehuo), in contemporary usage yaobian refers to the desirable form of rehuo in Yixing wares.

The earliest rehuo zisha wares can be traced to the mid-to-late Ming, when zisha wares were in their infancy and the methods of firing had yet to mature. During this time, some Yixing wares were fired in mixed kilns with Yixing Jun wares (“宜兴均陶”)[2]; the glaze on Jun wares would occasionally vaporize and deposit onto nearby wares, including adjacent (unglazed) zisha wares, forming a sub-category of the rehuo flaw termed Fei You (飞釉, “Flying Glaze") by certain collectors[3].

Until the Ming dynasty, in many ceramic centers, yaobian firings were considered a bad omen, a sign of supernatural forces interfering with the successful firing of the kiln:

“A kiln transmutation took place during the Daguan period [大观, 1107– 1110 CE][4]. The red was like vermillion. . . . Such occurrences were seen as a type of witchcraft, and thus the potters would immediately destroy them into fragments.”

- Zhou Hui (周煇, l. 1126–1198 CE, Southern Song dynasty)

Many yaobian wares were thus immediately destroyed, with only singular prized examples left intact. In other ceramic centers, yaobian wares were an expected outcome, with the kiln controlled to produce such effects. Jian (建) wares (oil spot wares[5]) and Jun (均) wares of the Song dynasty, with their telltale sign of yaobian, were not considered flawed.