Origin & Production
Through generations of trial and error, the perfect tea bowl was formulated and it was called Jian Zhan. Jian zhan is a type of Chinese pottery originally made in Jianyang, a district in the northern part of Fujian province in China. The local clay is naturally rich in iron ions (approximately 8-10%).
The formation of the clay body is created in two ways; machine pulled or manually hand-pulled.
Whether the clay body is made by machine or by hand, the shape and formation are entirely dependent on the master’s skill.
Before the clay body is fired in the kiln, it is set to dry (aging process). When it is ready, the clay body is placed in an oxidizing atmosphere at temperatures in the region of 1,300 °C. During the firing process, the clay body decreases 30% in size. Every piece has a different balance of these elements depending on the temperature it was exposed to during the firing process.
After firing, the finished pieces are carefully dipped into naturally blended glazes made from similar clay used for forming the body.
Once the Jian glaze has been thoroughly melted, crystals are separated from the molted glaze and the remaining glaze becomes high in iron oxide. During the burning process, some of the glazes will drip down the side, creating pooling of the liquid glaze. This is retained after firing as some of the finished product will have small beads of glaze at the base.
The firing of the Jian clay must be between 1300 °C to 1370 °C in order to separate the molten glaze to produce a pattern called “hare’s fur”. This phase separation of the iron-rich glaze was also used to produce the well-known “oil-spot” (油滴), “teadust” and “partridge-feather” (鷓鴣斑) glaze effects. Tea oils are slowly absorbed into the cup, altering the way the crystals refract light by magnifying the view. This effect grows through constant use of a Jian Zhan tea bowl, making it more beautiful over time.
The Jian dragon kilns were used in the Song Dynasty and were among the longest in China. Modern technology is used today with environmentally-friendly electric heating as the Jian clay needs to burn for 24 hours or so. After almost 20 years of research and experimentation, there is a 90% fail rate of creating Jian Zhan.