Tenmoku is a family of glossy, dark iron glazes, usually deep brown to black, that break to rusty brown where the glaze thins over edges and texture. They contain a high proportion of iron oxide.
What Is Tenmoku?
The name comes from Tianmu mountain in China, associated with dark-glazed tea bowls that Japanese monks brought home and prized. Classic tenmokus are high-fire glazes with roughly 8 to 12% iron oxide, fired in reduction, and they show beautiful variation from glossy black to amber and rust.
Because the colour depends on thickness, tenmokus reward texture, throwing lines and carving. Thick areas pool black, while rims and ridges break to warm brown. Some variations develop oil-spot or hare’s-fur effects under the right firing conditions.
Many tenmoku recipes and commercial glazes are now made for cone 6 oxidation, and they give a similar look in electric kilns. They are often used as the base in layering, because many glazes over tenmoku develop interesting colours.
As with any glaze, fire a test tile on your own clay first, since iron in a dark clay body can shift the colour noticeably. A thin and a thick coat side by side on one tile show the full range.
This pottery glossary entry from Le Studio Art Space is general educational content. Always follow the clay, glaze and kiln makers’ data for your own materials and equipment.