The Yōhen Tenmoku Tea Bowl: A Chinese Bowl Long Treasured in Japan

Yōhen Tenmoku Tea Bowl

Look into this bowl and the black glaze seems to open onto a field of stars. It is a yōhen tenmoku (曜変天目) tea bowl, and the one discussed here, a National Treasure since 1953, is held by the Fujita Museum in Osaka. The photograph is an old one, said to date from 1954.

The bowl is Chinese. It was made at the Jian kiln (建窯) in Fujian province during the Southern Song dynasty, in the 12th or 13th century, and its maker is unknown. It has long been treasured in Japan, but it is not Japanese work.

Tenmoku (天目) is the name Japan gave to bowls like this. In the Kamakura period, Japanese Zen monks trained at temples around Mount Tianmu (天目山) in China and brought bowls home that took the mountain's name. The bowls themselves are Jian ware. When this one arrived is not known. The earliest owner on record is Tokugawa Ieyasu (徳川家康).

It has the classic tenmoku shape and a jet-black glaze. Across that glaze are the spots that give it its name: lapis blue, green and iridescent, like stars against a night sky. Of the three National Treasure yōhen bowls, this is the only one with spots on the outside as well.

The word yōhen (曜変) is often explained as "kiln transformation", but that is a different word. 曜 means shining or star, so the name describes how the bowl looks. "Kiln transformation" is 窯変, which is pronounced the same way.

How the spots came about is still debated. Some see a chance effect of firing, others a deliberate technique.

In Japan it was prized as a Chinese import (唐物), and the museum notes that such bowls are used for matcha.

Imagine holding it, tilting it slightly and watching the light move across those blue spots.

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