Tortoiseshell Tea Bowl, Southern Song dynasty (1127–1279), Cizhou ware. Stoneware with dark-brown and splashed-amber glazes. H.2-1/16 x Dia.6 in. Gift of Ruth and Bruce Dayton, 99.180.2 © Minneapolis Institute of Art 

The Cizhou region located in central Kiangsi province produced its best known wares during Southern Sung (1127-1279). This was a technically creative period when Chi-chou kilns introduced and pioneered new techniques of decoration including tortoiseshell glazes as well as paper cut, glaze resist and naturalistic leaf designs. Called tai mei wen in Sung literature, tortoiseshell refers to the shell of the hawksbill sea turtle from which the Chinese made a variety of decorative items. The glaze was apparently made by splashing wood or bamboo ash, probably as an admixture of slip, on the surface of the dark glaze before firing. Light-toned splashes formed in those areas receiving the ash.