How to Care for Nambu Ironware

Nambu Ironware, or "Nambu Tekki" in Japanese, is a traditional handicraft of Japan made in Morioka City, Iwate Prefecture of the Tohoku region.

Nambu Ironware have a rough texture due to casting using sand molds, are resistant to rusting, transfer heat evenly to water, and retain heat well.

Learn how to properly care for your Nambu Ironware so that you can continue to use it for a long time.


Nambu ironware has its surface covered with natural black oxide iron rather than a coating of synthetic paint, making it pure iron and resistant to rust. Therefore once you get the hang of it, maintaining is very easy.

However, once you have your Nambu Ironware, there is preparation process that requires you to do first for sure.

For Iron Kettle

Nambu Ironware kettles may need to be prepared for a process known as “Narashi (seasoning)" before they can be used.

By going through the seasoning process, creates a mineral film of water on the inside of the kettle, preventing from rusting due to the moisture and make hot water taste mellower.

Please follow the instructions below to the process of the seasoning for your new kettle.


  • Boil mineral water
  • Change the water and repeat
  • You are ready to drink!


  • Beware of empty fires
  • Repeat until the discarded water becomes clear.
  • Do not touch the film that forms on the inside of the kettle.
  • Careful not to burn yourself!

Things You Need:

- Nambu Ironware kettle
- 1 Gallon of mineral water (hard water) or drinkable tap water.

Step 1 Boil water

Fill the kettle up to the eighth part of the way with mineral water (hard water), and continue to boil it until it is reduced to about 1/3 of its original volume, being careful not to burn it dry.

Step 2 Change the water and repeat

Change the water and repeat the above process 3 or 4 times until the boiled water becomes colorless. (Depending on the water quality, the number of times may increase.)

Step 3 You are ready to drink!

When the boiled water turns colorless, it is ready to drink.

For Iron Teapot

Nambu Ironware teapots retain heat well, much better than glass or ceramic teapots, which makes your tea time more enjoyable.

Unlike kettles, most iron teapots have an enamel coating on the inside, so there is no need the seasoning process at the beginning of use. All you need to do is rinse the inside of the teapot and the tea strainer thoroughly with warm water before use.


  • You cannot boil water with an iron teapot.
  • Do not use metal scrubbers to polish enameled inside.
  • Make sure there are no moistures on the surface.

Nambu Ironware is made of pure iron of the highest quality, and water boiled in the kettle will contain iron that is good for your health, so it is recommended for people who want to take iron supplements naturally as well.

Also, taste of water boiled in a Nambu Ironware kettle will be milder, so you can enjoy Japanese tea at its best quality. We highly recommend the kettle when enjoying matcha or green tea.

Nambu Ironware teapots also retain heat well, so they are ideal for use with tea leaves that can be used to make tea repeatedly. As well as Japanese teas, you can also enjoy herbal teas and Chinese teas.


Nambu Ironware cannot be used in microwave, harsh detergents, or dishwashers.

The kettle should only be used to boil water over an open flame or stove top (Do not use oven to boil water). The handle will get very hot, so please use oven mitt or thick towels to hold it to avoid burns.

The iron teapot must not be placed over an open fire or stove to boil water. This will cause peeling of the enamel. The iron teapot should only be used for making tea, in the same way as a ceramic or glass teapot.

Also, we recommend that you always use a coaster for your kettle or teapot, as placing them directly on the table may cause stains.


To care for your Nambu Ironware kettle 

After each use, just be sure to transfer or discard all remaining hot water inside of the kettle. There is no need to wash it with detergent, but if the kettle cools down with water still in it, it can cause rusting.

After draining the hot water, take off the lid and dry it with the residual heat of the kettle or over low heat.

In any case, do not leave any moisture on the kettle. The inside of a kettle that has been seasoned is still fine, though if the surface remains moist for several hours, it will cause of rust.

To avoid destroying the inside film created during the seasoning process, be careful not to scrub or touch the inside of the kettle. To clean the surface, wipe with a dry cloth especially lid and spout. 

To care for your Nambu Ironware teapot

After use, rinse the inside of the teapot and the tea strainer well with water or warm water, and wipe the entire surface completely dry with a dry cloth before storing.

Leaving water on the surface can cause rust, but the rust that occurs is not harmful to your health.

If you want to remove tea stains from the inside, pour boiling water inside and let it sit for a while, then clean it with dishwashing detergent and a soft sponge.

If Your Nambu Ironware Kettle Gets Rusty...

If you notice red rust on the inside of the Nambu Ironware kettle, or a metallic smell in the boiled water, it will not be harmful to your health, but if you are bothered by it, try this solution.

Rinse the inside of the kettle lightly with water, fill the kettle up to the eighth part of the way with water, add about a teaspoon of green tea or black tea, and boil the kettle for 30 minutes. Afterwards, make sure to discard the tea and tea leaves in the kettle.

This is a solution for stopping metallic tastes using a chemical reaction between Tannin (Tea Polyphenols) and iron contained in green tea, so use tea leaves that contain Tannin.


Nambu Ironware is a traditional craft that is durable and stardy, but also delicate and beautiful. They are simple to use, particularly the kettle, which is one of the best tools in Japan for boiling water for making tea.

Nambu Ironware can also be used in the kitchen to add a sense of Japanese atmosphere. We hope you find it useful in your daily life.


Nambu ironware, a representative of Japanese ironware, is a cast pure iron craft that has been continued since around the Edo period in the Morioka City area of Iwate Prefecture in the Tohoku region. The name comes from the region where it was made in the old days, known as the Nambu domain.Combining robustness and delicate design, Nambu ironware has more functional advantages than its attractive appearance.

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