Yue stoneware or porcelain bowl?

The French text of Lu Yu's Cha Jing made a specific distinction between Yue stoneware and Xing porcelain. In the note 47 on page 20, the translator even explains that the same character Ci (瓷) designates both porcelain and stoneware. So, even though Lu Yu used the same character about Yue and Xing bowls, the translator thought it necessary to translate Ci of the Yue bowl as stoneware and the Ci of the Xing bowl as porcelain.

Was it the correct translation? 

The first thing we have to ask ourselves is what is the difference between porcelain and stoneware? So, let's remember that porcelain has 3 characteristics:

1. Its body contains a large amount of kaolin (a white clay)

2. It is fired above 1200 degrees Celsius.

3. It is glazed to make it impermeable

Stoneware, on the other hand, is also fired at a high temperature, but its clay contains less kaolin and, while its color is more opaque. Stoneware is much harder than pottery, because it's fired at a higher temperature, but the glaze and the body aren't as refined and white and transparent as porcelain. Stoneware is like a step in the direction of porcelain, but it falls short of the perfection of porcelain.

So, while the very white Xing is easy to qualify as porcelain, the Yue celadon color bowl have caused the Catherine Despeux, the translator, a headache. The fact that its color isn't pure white, but green-blue celadon, the translator thought is better to qualify it as stoneware. And it's true that some Yue wares could still be quite coarse during the Tang dynasty and for which the term stoneware is a better description than porcelain. However, these are not the bowls that Lu Yu had in mind! When he writes that the Yue bowls were better than Xing porcelain bowls, he writes that their surface was like ice when Xing bowls are more like snow! This means that the glazing is of high quality. And the body of the Yue bowls Lu Yu described must have had a large amount of kaolin, white clay, because otherwise the celadon color would have had a darker hue. Indeed, the secret color bowl from the Famen temple (see below) is quite light in color and supposes a light color clay containing kaolin.

It's actually quite ironic that the translator didn't quite catch the profound meaning of Lu Yu's words about Yue bowls. Lu Yu thought that people were mistaking in regarding Xing bowls as superior to Yue bowls. From this perspective alone, it didn't make sense to qualify the Xing bowls as the most accomplished level of ceramics, porcelain, and the Yue bowls as the inferior stoneware. No, he felt that Yue and Xing were both porcelain, but that Yue bowls had the nicer color, which is also the more suitable to the tea drunk during the Tang dynasty.

Book: "Imperial treasures: Relics from the Famen temple underground palace"

This also reminds us that porcelain in China is often summarized with 4 characters: South celadon, north white. Indeed, most 'white porcelain' kilns were located north of the Jiang river, while most celadon kilns were located south!