Tenmoku

Jian ware tea bowl shapes are conical in form with a slight indent below the rim.

[2] The emphasis is on the ceramic glaze, where a number of distinct effects can be produced, some including an element of randomness that has a philosophical appeal to the Japanese.

Tenmoku takes its name from the Tianmu Mountain (天目 Mandarin: tiān mù; Japanese: ten moku; English: Heaven's Eye) temple in China where iron-glazed bowls were used for tea.

[5][6] According to chronicles in 1406, the Yongle Emperor (1360–1424) of the Ming dynasty sent ten Jian ware bowls to the shōgun Ashikaga Yoshimitsu (1358–1408), who ruled during the Muromachi period.

Three of these vessels from the southern Song dynasty are so highly valued that they were included by the government in the list of National Treasures of Japan (crafts: others).

To fire down a kiln, the potter continues to add a limited amount of fuel after the maximum temperature is reached to slow the cooling process and keep the glazes molten for as long as possible.

Tenmoku glazes can range in color from dark plum (persimmon), to yellow, to brown, to black.