Daily Care for Nambu Tekki Ironware


Native & Co Cast Iron Kettle S

History of Nambu Tekki Ironware

Nambu Tekki Cast Ironware is said to have started in the 17th century by the Nambu family who were ruling the northern part of the Iwate prefecture. In 1975, Nambu Tekki Cast Ironware was officially certified as a Traditional Craftwork of Japan. Boiling water in cast iron mellows the flavour, making it the perfect kettle for bringing out the subtleties in delicate teas as well as removing the bitterness in stronger, harsher teas.


Introduction to Nambu Tekki Ironware 

The steps to creating require patience and precision, each involving meticulous hands-on work. First, the molten iron is poured into sand molds and left to set. Then the craftsmen remove burrs, which are the raised rough edges made by excess iron from individual casts before applying a rustproof coating to finish.

This casting process gives a strong presence to Nambu tekki ironware, earning its widespread popularity. The traditional craftsmen make iron kettles by firing them in a furnace to oxide the metal, then apply black urushi lacquer to finish. The iron kettle are fired to give the inside a layer of protective film to prevent rust and limescale from building up inside. As the kettle is only meant for boiling water, remove excess moisture with a clean, dry cloth. There is no need to use soap or any other cleaning utensils.

Instructions for Care

Before first use:

  1. Rinse the inside of the kettle with lukewarm water.

  2. Fill the kettle with water and place over medium heat to bring to a boil.

  3. Discard the water and repeat the steps above three times to season the kettle.

 Daily care:

  1. When boiling water, leave the lid ajar to prevent from spilling over.

  2. After each use, pour out the contents and rinse with water only. 

  3. Remove any excess moisture with a dry cloth.

  4. Turn the lid upside down to air dry.


  1. Do not leave water inside for long periods of time, as it will cause the iron to rust. 

  2. Gently scrub the rust with a tawashi or a soft scrubbing brush and rinse with water.

  3. Fill the kettle with used green tea leaves and water. Let it boil for 20 minutes, then turn off the heat.

  4. Leave overnight and discard the contents. 

  5. Boil water in the kettle to see if the water is clear. If not, repeat the steps above three times. 

Cast Iron Kettle

Inside most cast iron kettles, there are two urushi spots. These spots indicate where the two nails used for securing the internal mold was located. Due to the nature of urushi, these two spots tend to overheat. Therefore, it is important to allow the tetsubin to heat up slowly when boiling water. The intense heat of an induction will expand the iron, which contracts as it cools down.

The internal film can be destroyed from boiling the kettle without any water inside. The tetsubin must not be heated when it is empty, as the temperature can go above 100°C. This may give stress to the metal and burn the two urushi spots on the bottom, causing it to leak or even crack. When replenishing the tetsubin, make sure that there is some water inside and do not add cold water.

After using the tetsubin for a few days, some red spots may appear inside. Do not scrub or wash these spots away, as it is a natural reaction to minor minerals. After a couple of weeks, some white spots may appear inside. This is a layer of natural minerals that slowly builds up after each use. Do not try to remove this layer, as it enriches the flavour of water and help prevent rust from forming.