Traditional Raku white clay, Cobalt oxide (blue), Chrome oxide (green), Copper oxide (light brown, red), Black Raku glaze (Kamo River stone), natural wood ash glaze, Fired in Black Raku kiln

This yakinuki-type Black Raku tea bowl, titled Hekikai Mugen (碧海無限, Infinite Profound Blue), was made in 2003 by Raku Jikinyū XV and represents a mature exploration of form, color, and firing within the Raku tradition. Formed from traditional Raku white clay, the bowl is globular yet deliberately distorted into what Jikinyū has described as a “boat-type” shape, an association based purely on physical resemblance rather than symbolism. The form balances a deeply enclosed interior with the outward tension of its stretched contour, animated by subtle undulations that Jikinyū likened to musical rhythm.

The interior is coated with a traditional Black Raku glaze made from Kamo River stone, while the exterior surface is articulated with brush-applied colorants including cobalt blue, chrome green, and traces of copper red. Fine vertical lines in black and natural ash glaze contrast with the bowl’s horizontal movement, creating layered visual depth. Unsealed and numbered on the bottom of the box as the 116th work in a series of unsealed bowls, Hekikai Mugen marks a systematic exploration of a form that Jikinyū would continue to develop in varied iterations in the years that followed.