Jian ware tea bowl with metal rim

Dark-glazed, dark-bodied bowls from the Jian-ware kilns in northern Fujian Province first entered Japan in the early 13th century, brought back by Japanese Zen monks who had learned the custom of drinking whipped powdered tea during their years of study at Chinese monasteries. Fujian was a center for tea plantations, and the dark, deep-sided, thick-walled bowls from the local kilns were considered without equal for keeping the tea warm after it was prepared directly in the bowl, by whipping a spoonful of powder in boiling water using a bamboo whisk, and for accentuating the fresh green color of the beverage. Japanese called the bowls Temmoku after one of the major monasteries that trained Japanese monks, Tianmushan, in Zhejiang Province. 

The beautiful feathery texture that sometimes developed in the glaze of Temmoku bowls was known as "hare's fur."  Since the iron-rich glaze tended to run, leaving the rim bare, owners often had the rough edge covered with a band of gold, silver, brass, or copper.