Iwachu cast iron (history, products, teapot use and care)

Iwachu Castings Works foundry worker

If you are looking for a Japanese cast iron teapot or kettle, you’ll come across a company called Iwachu. Whether you want a bright and cheerful teapot or a traditional kettle, Iwachu has you covered with their wide range of cast iron hollowware. And with over 100 years of expertise, Iwachu makes some of the best cast-iron teapots, kettles, and cookware.

This article covers:

  • Company information
  • History of Iwachu
  • How teapots and kettles are produced
  • Learn about popular products
  • Helpful tips to use and maintain your Iwachu ironware
Iwachu Casting Works
Foundry worker gently removing a clay mold. Great care is taken not to damage the mold.

Table: Company information

Iwachu origins

The company has its origins in Morioka. And is located in one of the two major cast-iron regions in Iwate Japan

2 Chome-23-9 Minamisenboku,
Japan 020-0863
Google Maps


Iwachu was founded in 1902 by Sueyoshi Iwashimizu


Iwachu is owned by N & I Asia Pte Ltd. A Japanese company headquartered in Singapore.
(N & I Asia Pte Ltd website)

40 Jln Pemimpin, #04-11 Tat Ann Building,
Google Maps

Type of casting

The foundry is a big operation, and most of the products are made using the green sand-casting method.

Signature product

Iwachu is best known for its range of teapots.
But they also have a beautiful selection of brightly colored teapots and a line of cast-iron cookware.

History of Iwachu Castings

The Iwachu brand was founded in 1902 by Sueyoshi Iwashimizu, in Iwate Japan. Iwate is the largest region in Japan, producing cast-ironware called Nambu or Nanbu Tekki, depending on the translation. If you want to learn more about Nanbu Tekki and the 900-year-old industry, click the link.

History of Iwachu )photo of a festival in Morioka Japan)
Iwachu is located in Northern Japan. Here is a festival in the city of Morioka.

The founder of Iwachu Castings

At a very young age, Sueyoshi loved the charm of Nambu Ironware and became an apprentice in a local foundry. He learned all about making high-quality Nambu Ironware during his apprenticeship. And after years of study, Sueyoshi became one of the most skilled Nambu craftsmen in the region.

Sueyoshi faced many challenges when it came to making Nambu ironware. War ceased production at one time as resources were diverted to the war efforts. And sadly, many older pieces of ironware were melted down and repurposed during this time.

Nevertheless, Sueyoshi prevailed and kept the Iwachu brand alive. Eventually, Sueyoshi’s two eldest sons took over the business. The eldest son, Yukichi, who began helping the family business when he was 12 years old, inherited his father’s craftsmanship. While Sueyoshi’s second son, Takiji, had Sueyoshi’s cheerful spirit and keen business sense. The two of them worked together to keep the Iwachu brand going strong well into the future.

Today Iwachu remains is one of the most respected ironware brands in Japan, and the company produces over 1,000,000 products annually.

Iwachu cast iron teapot
A beautiful selection of Iwachu cast iron teapots. I think the yellow one is my favorite.

The current owners of Iwachu

Iwachu is owned by N & I Asia. The parent company was founded in 1993 with just three employees. And has expanded to include some of the most trusted and well-known Japanese brands, including:

  • Swiss Diamond
  • Nikko
  • Tanita
  • Zojirushi (which is the most popular rice maker brand in Japan)

N & I Asia similarly run Iwachu to the way Zwilling J. A. Henckels operates Staub. A very hands-off approach. This allows Iwachu to maintain its quality control and expertise in casting. And become more creative with their designs and colors.

Today you can purchase teapots of all shapes and sizes, and you can choose from a wide variety of colors.

Brightly colored Iwachu teapots
Iwachu has the best selection of colored cast iron teapots available. I took this photo in the Iwachu factory store in Morioka.

Iwachu cast-iron kettles

Iwachu makes beautiful Tetsubins or cast iron tea kettles. These are handmade by their in-house artisans. Tetsubins boil water for tea and are not coated inside, making them more susceptible to rust. However, a method of oxidization reduces the chance of rusting. They are traditionally used over open flames. However, today you can use a tetsubin on multiple heat sources.

Display of Iwachu Tetsubins
Iwachu makes a variety of cast-iron kettles. The pictures behind the kettles are the craftsmen who made each of them.

Iwachu cast iron teapots

Iwachu cast iron teapots are used for brewing tea and cannot be used over an open flame. But because of the enamel coating, the teapots are nonporous and easy to clean. The teapots also come with a handy removable infuser to make cleaning a breeze.

The Process Of Making Iwachu Tetsubins

Cast-iron tea kettles or tetsubins have been used for more than 400 years to boil water for tea. They are made by a master craftsman known as a kamashi. To become a full-fledged kamashi, these craftsmen study for a minimum of 15 to 40 years. There are about 65 steps needed to make one cast-iron tetsubin. Most of these steps are done manually. Here is an overview of the process in the Boonie Hicks guide to cast iron kettles.

Iwachu cast iron foundry worker
Iwachu artisan making a Tetsubin. He is coloring the Tetsubin with a plant-based lacquer called Ohaguro.

How do Iwachu make their cast iron kettles?


Process of making Tetsubins kettles

Concept Design

First, the craftsmen design the Tetsubin.


Next, the drawing is copied to an iron plate about 1.5 mm thick.
And cut out to make a grinding plate.

Clay mold is formed
to the desired shape

Sand and clay are mixed to make a mold of the Tetsubin.
The mold is cut using a tool called a cow and applied to the grinding plate.


Before the mold dries, the pattern or design for the Tetsubin is hand-pressed into the mold.

Mold is assembled

Then, the outer mold is assembled with the inner mold.

Iron is poured

Iron is melted at 1,400 ° C to 1,500 ° C in an electric furnace.
A tool called a Yugumi is used to pour the hot iron into the space between the outer mold and the inner core.

Mold is removed

The cast iron solidifies and is released from the mold.
Then, the inner core and outer molds are removed. 

Kettles smoothed

Raw edges are buffed out.


The kettle is then fired in a kiln.

Color is applied

The iron kettle is heated to about 250° C. Lacquer is then baked on the surface of the kettle.
A black patina called Ohaguro is applied to the outside, at a temperature of about 100°C to 150°C.


The kettle is finally polished with a mixture of green tea and vinegar to give a glossy finish.
Iwachu Castings Worker removing a clay mold
The Artisan is very carefully removing a clay mold. These molds can take half a day to make.

How are Iwachu cast iron teapots made?

The process of making cast iron teapots is somewhat different for Tetsubins. Cast iron tea kettles are made to boil water, whereas cast iron teapots are only used to make the tea. They are coated with enamel on the inside to prevent rust. Here is an overview of the process that Iwachu uses to make its teapots. I have also written an informative guide on cast iron teapots if you’re interested.

Sand Mold

Sand molds using special foundry sand are pressed into the desired shape.
An external mold is carefully placed into the mold. And will eventually form the hollow in the teapot.

Iron is poured

Iron is melted in a furnace at about 1,500° C.
The iron is then poured into the mold. 

The Sand mold is removed

When the iron in the mold solidifies, the mold and gate-mark are removed and checked for imperfections.
The teapots are then placed into a centrifuge to remove sand and smooth edges.


Once the sand is removed, the teapot is polished and buffed individually by skilled foundry workers until the surface is smooth and edges free of rough edges.


A feature of ironware from Japan is the oxidization process. The teapot is heated to a high temperature in a kiln, oxidizing the surface to prevent rust.


Then enamel is then baked on the inner surface at a high temperature. 


The craftsman then hand-paint the outer surface of the teapot. 

Iwachu cast iron products

Looking for a new cast-iron teapot? Check out the Iwachu traditional and brightly colored teapot?

Full display is Iwachu cast iron teapots
Wow. Great display of the range of Iwachu teapots. Iwachu teardrop teapots bottom left. Iwachu Hailstone pattern bottom right, and Hobnail Arare pattern teapots on the shelves.

Hailstone Teapot Series

This authentic Japanese handcrafted Hailstone Teapot Series features the classic Hailstone pattern. The teapots are available in a variety of sizes and shapes. The elegance and beauty of these teapots make them perfect for tea service. The 16-ounce teapot is ideal for a romantic tea service for two. And the 36-ounce teapot is suitable for a small group of friends.

Iwachu cast iron teapots (hailstone pattern).
Iwachu hailstone teapots look great, the pattern is traditional, but it looks very different than other designs.
This teapot is low and wide profile. It is a classical Japanese kettle shape, but it is very different from a standard-looking teapot.
And it had a bumpy exterior surface.


The teapot has a 16-ounce capacity. Or two standard cups.

Interior coating

This teapot is enameled on the inside.

Removable infuser

Yes, the infuser can easily be removed for easy cleaning.


The teapot is designed for brewing two cups of tea.

Where to buy

If you want to check out this cute teapot, here is an affiliate link to

All of the teapots in this series include a stainless steel infuser basket and have a rust-proof enamel coating baked on the inside. This makes them perfect for steeping tea but not suitable for use over an open flame. 

Iwachu Japanese Artisan Iron Teardrop Teapot Series 

This teardrop-shaped cast iron teapot from Iwachu is a contemporary take on a classic design. It features an elongated spout and a squat body. This design helps ensure a clean and smooth pour with no dripping. 

This particular teapot has a 23-ounce capacity and serves up to four. The Teardrop Teapot is available in classic matte black, turquoise, pink, and purple. An enamel coating on the inside helps resist rust.

Iwachu cast iron teapots (teardrop)
These modern teapots sure are stylish. This style is called teardrop.


This teapot has a modern, sleek yet timeless design.
It has a smoothmatte finish, and whether you are a traditionalist like myself.
Or, if you prefer modern designs, you will love the look and feel of the teapot.


23-ounce capacity or 2.8 full cups.

Interior coating

The interior is fully enameled.

Removable infuser

Yes, the teapot has a removable stainless steel infuser.


The teapot is designed for brewing 3-4 cups of tea.

Where to buy

You can check out this pretty neat looking teapot on Amazon
(affiliate link).

Iwachu Maple Leaf Cast Iron Teapot Series

Iwachu cast iron teapots (Maple leaf pattern)

This series features a unique maple leaf design. In Japan, maple leaves are admired for their beauty. This 22-ounce teapot is available in gold & black, bronze, green, and red. The colors are made to represent the beauty of autumn leaves. Like Iwachu’s other teapots, this one has a stainless steel infuser and baked porcelain enamel on the inside. It should not be used directly on the stove.


This design is so popular that other manufacturers copy the design.
However, if you want an authentic Japanese teapot, look to Iwachu.


This teapot holds 22-Ounces or 2.8 full cups.

Interior coating

The teapot is fully enameled.

Removable infuser

Yes, the teapot has an easy-to-clean infuser.


This teapot should hold 3-4 cups of tea, depending on the size of the teacup.

Where to buy

If you want to see this nifty teapot, click the link to Amazon
(affiliate link).

Iwachu Japanese Iron Teapot, Honeycomb Series 

This series of teapots feature an elegant honeycomb design. The Japanese have been using this hexagonal pattern as a template for samurai armor for centuries. The Honeycomb Series teapots are available in a 30-ounce capacity, which is perfect for tea service. They are all coated in enamel to resist rust. A removable stainless steel mesh infuser is included. Colors include classic black, gold & taupe, gold & cranberry, lavender & silver, gold & purple, and turquoise.

Iwachu teapot (Honeycomb pattern)
Cute little Honeycomb teapots


The surface of this Iwachu teapot is pebbly and gives teapot a real sense of individual character.


The honeycomb series comes in a variety of sizes.
However, it is also available in a larger 30-ounce capacity, which is just under 1 quart.

Interior coating

The teapot is enameled for easy cleaning.

Removable infuser

Yes, the teapot has a big wide stainless steel infuser.


With nearly a quart of tea, the teapot is ideal if you have a few friends around for tea.

Where to buy

To see this teapot, click the link which will direct you to Amazon
(Affiliate link)
Brett Standeven (Boonie Hicks) holding a Iwachu teapot
Hi guys, this is my own little Hobnail teapot

Iwachu Japanese Hobnail Arare Cast Iron Teapot Series

These teapots have a hobnail design. This is a classic Japanese teapot design preferred by tea connoisseurs for its simple beauty. The Hobnail series comes in a range of sizes from 20 ounces to 44 ounces, making them perfect for every occasion. They are available in classic black, copper, bronze, and many other color combinations.


This teapot has a traditional design.
It is the most familiar pattern many people will recognize.


This teapot has a 22-ounce capacity or around 3 cups of tea.

Interior coating

The teapot is fully enameled inside to protect it from rust and
the enamel lining makes the teapot easy to rinse out.

Removable Infuser

Yes, it has a removable stainless steel infuser.


A 22-ounce teapot is a perfect size for a couple or at work.
So you can enjoy a couple of cups of tea while you’re at your desk.

Where to buy

If you want to see a classic Iwachu teapot, Check out on Amazon
(affiliate link).
Brett Standeven at Iwachu
I had a great time visiting and learning about Iwachu cast iron. Lots of thanks to the friendly staff at Iwachu.

Iwachu Cast Iron Tea Kettles and Teapots – Use & Care  

  1. Before you use your teapot or kettle, wash it with warm water. Then, dry the inside and outside of the kettle with a cloth. 
  2. Never boil water in an Iwachu Cast Iron Teapot. These are coated on the inside with an enamel lining. Boiling water in these teapots will damage the coating.
  3. Either use an Iwachu tea kettle that is safe on the stovetop. Or boil water separately in another vessel.
  4. You might notice white marks or red spots on the bottom of the teapot after about two to three weeks after first use. This is normal and is no cause for concern. It keeps rust from forming. Plus, in Japan, this buildup is considered healthy as it contains iron. 
  5. You might notice indentations on the bottom of your Tetsubin or cast iron teapot. This is normal. They are formed during the process of making the teapot. If you want to learn how to make a great-tasting cup of tea using a cast iron teapot, click the link.

Iwachu cast iron teapot care

Follow these care steps. 

  1. After you are done using the teapot, pour out the excess water from the teapot. 
  2. Then allow the teapot to dry with the lid off. 
  3. To keep the surface of your teapot looking shiny, soak a soft cloth in tea. Then, gently polish the outside of the teapot. 


  1. Don’t leave tea standing in the teapot for long periods.
  2. Also, expose the teapot to salt or oils. 
  3. Finally, don’t use harsh cleaners or detergents. This could damage the interior lining.  

Final Thoughts

When you purchase an Iwachu teapot, you can be sure that you are getting an authentic Japanese cast iron teapot. The use of cast iron teapots dates back centuries when they were part of the traditional Japanese tea ceremonies. Iwachu has maintained a classic, timeless aesthetics in its teapot design.

Iwachu is known for having some of the finest teapot craftsmen in Japan. The company has been producing teapots for more than 100 years. Every Iwachu teapot is carefully designed by an artisan. So, no two teapots are alike.

With the proper care, an Iwachu teapot will last forever. It won’t discolor, chip, or rust. No matter which Iwachu teapot you choose for your tea service, you can be sure that you will get a high-quality, timeless piece of ironware.



  1. Hello, I’m a bit confused about the presence of inner surface called kamayaki in some tetsubins.
    It does affect the taste of water?

    • Hi Fabio

      Thanks for getting in touch.

      I’ve only seem the term “Kamayaki” in reference to Tetsubins on one website. The writer is likely referring to the taste of water from a tetsubin with a rusted surface. I’ve heard purists say using an old rusty kettle enhances the flavor of the water. Many of these enthusiasts also use natural spring water rather than regular tap water. Because of the higher mineral content and water softness.

      This level of tea expertise is beyond my knowledge. And I’m happy using a tetsubin that has undergone a second firing to prevent rust. I also use regular water from the tap. Using bottled water for a cup of tea is beyond my pay grade. But no doubt using spring water, boiled in an old rusty kettle would change the taste of the tea.

      Hope this helps.

  2. Any experience with a “Tokyo Grill”? This is a cast iron assembly of 4 main components that include a charcoal pot and 5 individual “petals” with a bowl in the center.

    • Hi Dennis

      Thanks for sending in a question, Unfortunately, I haven’t had the pleasure of using the grill as you describe. I’ve been in Japan for quite some time, and haven’t seen anything like it. I’d love to come across one. Thanks for letting me know about know about the flower inspired grill. I’m guessing the design is Sakura shaped. I’ll be sure to keep an eye out for one.

      Cheers Dennis

  3. I have one of these teapots, and I’m wondering how old it might be? I haven’t seen the style of this one on this very helpful article.

    It has lines circling the teapot and lid, with a lotus style lid handle. It doesn’t have the hobnail or hailstone or other styles I see on this article. It bears the mark of the Iwachu foundry under the spout, which is bordered by a rectangle. It has a strainer inside which appears quite old but is apparently stainless steel.

    Thanks for any help, and for this article!

    • Hi Gabe

      Thanks for getting in touch, and I’m pleased you’ve enjoyed the article.

      Unfortunately, I can’t estimate the age of your teapot. But from the description of the strainer it sounds like an older model. Iwachu strainers today are made with stainless steel mesh. Older strainers on the other hand are colander like in appearance, and have holes in the bottom to steep tea.

      The enameled teapot is a fairly new invention, so your pot is unlikely to be considered vintage, but just give it time and it will be.

      I’m not sure of your exact model, but you might want to Google search “Iwachu Tsuki” and “Iwachu Senbiki”. These teapots have lines around the circumference of the teapot and could be similar to your earlier Iwachu teapot.

      Hope this helps, and enjoy your teapot.

  4. Hello, is there a difference between iron used for Iwachu’s tetsubins without coating and iron used for their enamelled teapots? Thanks a lot, Mau.

    • Hello Mau

      Thanks for your question. There is little difference in the iron used between Iwachu enameled teapots and unlined Tetsubins.

      However, the process of manufacturing the two vessels is completely different. You probably have already noticed the price difference, Iwachu enameled teapots are produced on a large scale useing modern manufacturing techniques. Tetsubins on the other hand are made using traditional clay molds, and the process requires a great deal of expertise and steps to produce each kettle.

      Thanks Mau hope this helps.

  5. Thank you for the writings.
    I am confused at the usage of cast iron teapot between Oitomi and Iwachu brands.
    In this article, it mentions that Iwachu tetsubin is used over open flames. However, the tetsubin recommend by Oitomi is supposed not to used over the flames or just weak flames. So, what is the difference between these two brands of the tetsubin?

    • Hi P.S.

      Thanks for reaching out.

      Both Iwachu and Oitomi are well respected Japanese brands. And have a wide selection of products. But generally teapots cannot be used on any heat source because of the enamel lining.

      Tetsubins have a different purpose and that is to boil water. So you should be able to hang a traditional tetsubin kettle over flame. Unfortunately, the term tetsubin is commonly used in English to describe a Japanese teapot. However, the Japanese word for a cast iron teapot is Tetsu Kyusu. So many websites inaccurately describe their products.

      Nearly all Japanese cast iron teapots have an enamel lining. But because of this confusion Japanese manufacturers make some teapots without an enamel layer. Instead these teapots are seasoned with vegetable oil. Similar to cast iron cookware. These teapots can be used on moderate heat to low heat. I think these work well on induction heat.

      So you have three options

      1. traditional kettle to boil water (usually very expensive)
      2. enameled teapot to steep tea (durable and easy to clean)
      3. seasoned teapot to boil and steep tea. (dual purpose but harder to clean, needs to be used on lower temperatures)

      I have a few different teapots but it’s the enamel teapot I reach for first.

      I have visited both foundries and they both make great products. Go for one you think looks the best.

      Have fun


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