The Art of the East Asian Potter
Cakes of tea leaves were first imported to Japan from China in the Tempyo period (710-794 CE). The plant itself was brought to Japan by a priest named Eisai (1141-1215), who wrote "A Treatise on Life Preservation by Tea Drinking" in 1214. By this time the Chinese had developed specialized tea equipment and tea-tasting games, but it was the Japanese who linked Zen Buddhism, art appreciation, and tea tasting togetehr in an aesthetic ceremony. Spiritualized through the influence of Zen and enhanced by the forms and textures of calligraphy, painting, and pottery, the tea ceremony and all of its components became a major outlet for Japanese aesthetics in the 15th century.
Raku, Bizen, Karatsu, and oribe wares are central to the tea ceremony in Japan. From a Western perspective tea wares sometimes appear to be crudely executed, but they are purposely created with irregularities which emphasize the natural properties of clay and directly reflect the forming and firing processes that produce them. For example, tea bowls are never perfectly round, reflecting the belief that nature is never perfect. The sense of touch also is important: the undulations of the body and the rim are designed to feel pleasant to the hand and mouth when drinking, and the teabowls are always thick-walled so that they can be held without the risk of burning.