China has a long history of pottery making. Shouzhou porcelain has been known for its yellow-glazed wares since the fifth century, that's almost 2000 years ago.
In Anhui province, there are remains of six major porcelain-making sites around the Shangyao township. Among them, the Guanju site is best known. In the wilderness outside the town are scattered the remains of numerous kilns, the first of which were built in the fifth century. Before falling into disuse, they had produced the famed Shouzhou porcelain. With its exquisite yellow glazing, the Shouzhou porcelain was at its height in the Tang Dynasty around the seventh and eighth centuries.
After examining the porcelain shards unearthed around the kiln remains, experts concluded that Shouzhou porcelain wasn't made from the best of raw materials. The clay lacked purification and washing. Some pieces even contain foreign matters like small pebbles and sand. The beautiful glazing was a result of technological superiority.
In the making of Shouzhou porcelain, there is another advanced technology. Before going into kilns for firing or baking, delicate wares were put into stone boxes. Besides providing even heating, this method also keep the clay wares from being damaged by dust in the kilns.
(CCTV February 27, 2004)