By the Jin dynasty, the mass production of ceramics resulted in simpler shapes and more spontaneous and freer decorative styles. Cizhou ware, which derives its name from Ci County in Hebei province, was produced for a popular domestic market at a number of kilns in northern China, mostly in Hebei but also in Henan and Shanxi provinces, from the late Tang period onwards. Cizhou kilns specialized in painted decoration, including the first overglaze enamels ever made in China. The early shapes and glazes were influenced by the white wares of the Tang dynasty (618-907 C.E.). This unusually large octagonal pillow captures the spirit of the Jin era. The grey stoneware biscuit is covered with white slip under a transparent glaze. The surface, painted in underglaze iron black, shows a bird perched on a bamboo stalk. The sides are painted with stylized palmette scrolls, while the base is stamped with a three-character mark reading Zhang jia zhen (pillow by the Zhang family). This family of potters in Hebei was known for its production of Cizhou ceramic pillows. Established at the end of the eleventh century, the family workshop was active for the next three hundred years.