Yōhen Tenmoku, Ryūkō-in
Masterpiece
National Treasure
Collection: Ryūkō-in
Height: 6.5–6.6 cm
Mouth diameter: 12.0–12.1 cm
Foot diameter: 3.8 cm
Foot height: 0.4 cm
Along with the Inaba Tenmoku and the Yōhen from the Fujita Art Museum, this is a masterpiece designated as a National Treasure that has been passed down as a “Great Treasure.” Together with calligraphy by Mikan, it was treasured as a temple treasure of Daitoku-ji’s ancient sub-temple, Daitō-an (the family temple of Tsuda Sōyuki). The fact that Priest Kōgetsu inscribed the inner box lid also attests to the bowl’s distinguished lineage.
The clay is nearly identical to that of the other two National Treasure bowls, but compared to the one in the Fujita Museum of Art, it has a slightly stronger bluish-black hue and, perhaps due to the trimming, exhibits a dull, metallic sheen. It appears to have been thrown on a heavy, fast wheel; the shape of the bowl is clean and well-proportioned, and the trimming marks around the footring are superb. The outer rim of the footring forms two distinct tiers due to the trimming, giving it an appearance reminiscent of a bamboo-joint footring—a feature rarely seen in other Tenmoku bowls.
The application of the glaze and the manifestation of the yo-hen patterns closely resemble those of the piece in the Fujita Museum of Art. Specifically, the glaze is a deep black vitreous glaze; in areas where the glaze layer is thick, the lower and upper glazes blend well, forming yo-hen and rabbit-hair patterns on the surface. A kind of oil droplet, perceived as a silver grain, interferes with the iridescent film on the surface; when oblique light is shone on it, this grain sinks, and the glaze surface around it shines in a ring-like pattern.
However, at the rim, where the glaze layer inevitably becomes thinner, the glaze color is pale and no yohen phenomenon occurs, so the color of the underlying clay shows through, appearing iron-colored. In contrast to the various yohen effects on the interior, the exterior shows none at all. Although the glaze texture is nearly identical, the yohen effect likely does not occur easily due to differences in firing conditions. Instead, a network of silver-colored, mesh-like craquelure runs across the surface, subtly intertwining with the iridescent film to emit a dull blue glow. What this craquelure-like pattern is and how it came to be remains a mystery for now.
Furthermore, around the stepped band at the outer rim, fine rabbit-hair-like cracks run, which appear to shimmer silver in the light. Aside from a single lacquer repair on the rim, the piece is in perfect condition.
It is often suggested that Yo-hen Tenmoku may have been produced in a different kiln than standard Ken-zan, but this remains unclear at present. According to Dr. Plummer’s survey of the Ken-zan kiln site, not a single fragment of Yo-hen was found; however, since such Yo-hen Tenmoku are the product of an extremely rare, accidental phenomenon, it is difficult to definitively conclude that they were not produced at the Ken-zan kiln.
(Masahiko Sato)
