This elegant jar is a rare descendant of wares developed in the Yao-chou area of Shansi province during the T'ang period (618-907). Although the Yao-chou kilns are most famous for celadons produced during Northern Sung (960-1127) and Chin (1115-1234), the region had a longer and more ancient history in the production of black and related wares. Northern "tea-dust" glazes of this period are extremely rare and take their name from later porcelains in which a lighter glaze is peppered with specks of matte glaze blown onto the surface giving an appearance of powdered tea. The earlier glazes, like the one here, were achieved by slightly under firing the iron-rich glaze material.