Yohen Tenmoku Maeda family
Important Cultural Property
Height: 7.0–7.3 cm
Mouth diameter: 12.3 cm
Foot diameter: 3.7 cm
Foot height: 0.7 cm
This is a Yōhen Tenmoku that has been passed down through the Maeda family of Kaga. It is said that there have been only six Yōhen pieces since ancient times, but today we know of only four: the Inaba Tenmoku (National Treasure, Seikadō Museum), which was passed down through the Inaba family of Yodo; the Yōhen (National Treasure, Fujita Art Museum), which was passed down through the Tokugawa family of Mito; the Yōhen (National Treasure) passed down to Ryūkō-in Temple in Kyoto; and this bowl. However, it is a precious object found nowhere else in the world outside of Japan, and it should be called a treasure of Chinese ceramics.
Unlike Yuteki, the mystery of why Yōhen occurs has not yet been solved. It is undoubtedly the result of chance and the precise control of the firing temperature, but we do not yet know exactly what conditions of the fire produce this effect. However, according to the research of Dr. Kazuo Yamazaki, we do know that an extremely thin film—one ten-thousandth of a millimeter thick—forms on the glaze surface, and it is this thin film that disperses light rays, emitting a mysterious iridescent glow of seven colors. When a thin film forms on the glaze surface, a phenomenon similar to that seen on the wings of a jewel beetle, a soap bubble, or oil dropped onto water occurs: the thin film acts as a prism, dispersing light rays and emitting a rainbow-colored radiance. When strong light hits it, the radiance shines vividly; when the light is dim, the yo-hen appears dull and subdued.
This yo-hen passed down in the Maeda family does not exhibit as vivid a radiance as the yo-hen at Seikado, the Fujita Museum, or Ryuko-in; however, when light is shone on its interior, blue, green, pink, and purple yo-hen patterns emerge on the glaze surface as shown in the illustration, emitting a mysterious radiance from the jet-black glaze. The grains on the outer surface resemble those of a “mushi-yuteki” (insect-drop) ware; while some emit a glow similar to the inner surface, they are not as vivid as those inside.
Furthermore, upon close inspection, the glaze surface is slightly indented only at the points where the yohen grains appear. Just like in Yuteki, this is likely a crystal formed where iron rust gathered in the indentations created when the glaze boiled, bubbles formed, and the moisture evaporated; a thin film then formed over it, resulting in the yohen pattern. The nature of this film and the cause of its formation are the mysteries of yohen.
This Yohen Tenmoku tea bowl, passed down in the Maeda family, is made of a coarse clay containing a small amount of iron. Due to the kiln conditions, the clay has taken on a black-purple, iron-like hue. However, this coloration is the result of the clay being carbonized or soiled, so the actual iron content within the clay itself is not as high as it appears.
Although the body is thick, the turned-up rim is relatively thin, giving the bowl a crisp, defined shape. It has a low, small foot, with a shallow groove carved into the foot’s interior. The jet-black glaze is applied thickly down to the waist of the bowl, and where it has run down and broken, it has pooled particularly thickly.
There is a pinhole in the center of the interior, and two chips of varying sizes on the rim; these have been repaired with lacquer, but no rim band has been applied.
Inner box: Gold-powdered pear-skin ground with silver-powdered characters reading “Yōhen” by Kobori Enshū
Outer box: Untreated paulownia wood with “Yōhen” inscribed on the lid
According to the Ganka Meibutsu Ki and Kokon Meibutsu Ruiju, this piece was once owned by Matsudaira Hizen-no-kami and later passed down to the Maeda family.
(Fujio Koyama)
