An original piece from Morioka, Iwate Prefecture, Japan.
Nanbu tekki (Jap: 南部鉄器), or Nambu ironware, were first made in the 17th century, when master craftsmen from Kyoto were invited to Morioka in Iwate Prefecture. Ever since, Nanbu tekki have been considered Japan's finest ironware. The masters' knowledge and techniques are heavily guarded and only passed on from generation to generation.
Cast iron (鋳鉄, chūtetsu), which is normally susceptible to rusting, is baked at 800°C using the special Kamayaki technique. In the process, the iron is specifically oxidised and activated and thus receives a natural rust protection.
The elaborate manual production requires more than 3 weeks. The mould, including the design on the outside surface, is formed by hand and can only be used for casting about five kettles. Japanese tetsubins are made much thinner and more delicately than Chinese copies. Usually, Chinese cast iron has considerably more manganese and therefore has to be cast thicker. The training for producing high-end Japanese tetsubins takes 15 years and has only been achieved by a handful of masters in Japan.
Coated only with Ohaguro (jap. お歯黒, engl. "tooth blackening"), a natural mixture of green tea, vinegar and iron sand.