ForMatter/Finishes/glaze/Tenmoku (iron-saturated black glaze)
finish_glaze_tenmoku

Tenmoku (iron-saturated black glaze)

glaze · patinated · tenmoku, 天目, Jian temmoku, iron-saturated black

A high-iron glaze that fires deep glossy black, breaking to rust-brown where the glaze runs thin over edges or relief. Tea bowls from the Jian kilns (Fujian, China, 12th-13th century) defined the look; Japanese tea masters imported them through the temple at Tianmu (whence 'tenmoku') and made them the most prized chawan. Reads as deep, oily, ancient.

Feldspathic glaze with 8–14% iron oxide as colorant, fired to cone 9–11 (~1280–1300 °C) in oxidation or light reduction. The high iron saturates beyond solution limit; on cool-down iron crystals precipitate at the surface giving the characteristic 'oily' reflection. Glaze surface fluid at peak temperature, runs to thin on edges where Fe³⁺ is preserved as rust-brown bare surface. Variants: oilspot tenmoku (iron crystals visible as silver-gray spots), hare's-fur tenmoku (iron streaks running with the glaze flow), partridge-feather tenmoku (mottled spots) — all the same chemistry, different cooling regimes.

character — deep oily black with rust-brown rim breaks, fluid running glaze, ancient register.

Finish properties

  • levelpatinated
  • subcategoryiron-saturated feldspathic
  • applies toceramic
Pairs with materials

Second life

reversibilityzero — fired ceramic glaze cannot be unfired; the glassy layer is permanent. Damaged or chipped glaze can be re-glazed and re-fired with chemistry-compatibility planning.
blocks substrate recyclingno
renewabilitymoderate — re-glazing and re-firing is a studio-renewability path for damaged ceramic; the constraint is the original-firing temperature (the re-glaze must fire below the original).

Robin Hopper *The Ceramic Spectrum* (Krause, 2nd ed.); Daniel Rhodes *Clay and Glazes for the Potter*.