This is a Song dynasty (12-13th century) Jian teabowl. The term Jian (zhan) is actually a japanese word, meaning; small bowl during ancient time.
It is made from a dark brown, coarse pottery. It measures 12,3 cm across and weighs about 285 grams. Bowls like these were copied many times, as fakes or as later made teabowls. They are very hard to determine as of the period. On my example I rely on the knowledge of two experts, a fellow collector and of course my own. Saying that, it is not an exact science.
There are a few things to look for;
- shape of the whole piece, footrim, proportions.
- clay, color, should be rough to the touch
- glaze, lustrous, running down the bowl. Thickening downwards, into drops. Slightly pooling to one side on the bottom.
- wear, irregular scratches from use, possible degrading of glaze, possible chips or cracks
- crazing, a unusual spiderweb irregular crazing under the surface.weight, this one 285 grams.
But these are not always applicable, and there is no knowledge than from an expert who handles these regularly.
These bowls are also called Temmoku or Tenmoku after a mountain in the Zhejiang area.These bowls were made in different kilnsites in Fujian province.
The shapes of Jian tea bowls and their glazes were designed for drinking Fujian white teas, showing off the tea and the beaten tea froth. The glaze is a combination of iron rich clay, with a glaze made from the same clay mixed with wood-ash.During the melting of the glaze the iron rich glaze separated and came to the surface as drops, wich ran down the bowl forming the typical streaks.