Tsuiki Copperware - A Traditional Japanese Craft Whose Beauty Has Reverberated Throughout History

Passing under Asakusa’s famous large red lantern with "Kaminarimon" (Thunder Gate) written on it, I made my way through the crowds of the Nakamise Shopping Street. Turning a corner and cutting through the Asakusa Hanayashiki amusement park, I arrived at Senzoku-dori Shopping Street in Oku-Asakusa, just north of Senso-ji Temple. It was then that I started to hear the rhythmic and powerful sounds of clanging metal coming from a two-story building that looked like a residential house in the middle of the busy shopping street. Peering through the glass windows, I could see that it was a shop full of shiny copperware of different shapes and sizes.

What Is Copperware?

Copperware refers to objects made from processed copper, including everything from cooking utensils to containers, musical instruments, lighting fixtures, temple statues and bells, and more. Copper has been used all throughout Japan since ancient times, and is commonly seen in temple bells that usher in the New Year or in statues of the agriculturalist Sontoku Ninomiya, which often adorn the fronts of Japanese elementary schools. The two places in Japan best known for their copperware are Takaoka City in Toyama Prefecture, known as the "City of Metal Casting," and Tsubame City in Niigata Prefecture, known as "The Land of Tsuiki Copperware.”

What Are the Characteristics of Copper Products?

Copper is both malleable and durable, making it an ideal material for a variety of objects. It’s also an excellent conductor, transferring heat 22 times faster than stainless steel when placed over an open fire. Copper’s high conductivity isn’t just efficient, it also prevents heat from concentrating in one place, which is why the bottoms of copperware pots and pans don’t burn easily. Additionally, the metal boasts excellent cold retention and antibacterial properties, which is why it’s so often used to make cookware. However, the greatest appeal of copper products is most likely their beautiful shine and color.

That being said, copperware also has its drawbacks, one of which is its tendency to rust. For this reason, Japan’s Food Sanitation Act requires that copper utensils, tableware, and cookware that come in direct contact with food must be plated with a layer of tin or silver.

Traditional Copperware Crafts: Hammering, Engraving, and Casting

In Japan, there are many traditional techniques for processing copperware. They can be broadly classified into three categories: hammering (shaping the metal by beating it), engraving (carving designs on the surface of the metal), and casting (melting the metal, placing it in a mold, and then cooling it down to harden it). "Tsuiki" hammered copperware, which was developed during the mid-Edo period (1603 – 1868) when craftsmen flowed from Sendai in the Tohoku region (north-eastern Japan) to Tsubame City in Niigata, is one of the most popular forms of processing the metal.

Tsuiki Copperware is produced via hammering by a craftsperson working with a single copper plate, hundreds of different hammers, and a "toriguchi" (also known as an "ategane": an iron tool used during hammering) to strike and shape the metal into a three-dimensional work of art. In fact, the word “tsuiki” literally means “to shape with a hammer or mallet.” The time required to make hammered copperware varies depending on the complexity of the piece, with some projects requiring up to a month of work. Since no two examples of hammered copperware are the same, it can be said that each piece is the manifestation of the craftsperson’s skill and soul.

For Quality Copperware, Visit the Dogindoki Store in Oku-Asakusa

To explore the allure of copperware, I visited Dogindoki, a long-established store with a history going back 99 years ago in the Senzoku-dori Shopping Street in Asakusa, Taito-ku, Tokyo. It was there that I talked to Tamotsu Hoshino, a third-generation copperware craftsman who started his training at the age of 18 and is now one of the few Edo-style copperware artisans in Japan.

Hoshino has always loved making things with his hands, and as the eldest son, he started thinking about taking over the family business when he was in junior high. He eventually apprenticed himself to a silverware craftsman, hearing that "silverware is more precise and more difficult to process than copper," therefore reasoning that if he first got experience working with a more difficult metal, it’d make learning about copper later on a little easier. After four years of making silverware, he returned to his parents' home and devoted himself to the art of copperware.

However, Hoshino laughed as he told me that the name of the store, which literally means "Copper and Silverworks," has nothing to do with his background in silverware manufacturing. Instead, it refers to his grandfather Ginjiro, whose name is spelled with the character for silver. "In the early days of the business, my grandfather added the character to the name of the store, and it just stuck around,” Hoshino said. The first floor of Dogindoki is the store, and the second floor is where the family lives. The store is divided into three areas: to the left of the entrance is the display area, to the right is the workshop where Hoshino hammers copperware every day, and the back is where the raw materials and furnace are located.

Hoshino’s Tsuiki Copperware-Making Process

1. Preparing the base metal: Using a special cutter, a sheet of copper "base metal" about 1 centimeter thick is cut into a circle or other shapes according to the size of the final product.

2. Annealing: Copper plates are very hard and must first be heat-treated in a furnace. After the material's properties are changed by the high temperatures, the base metal is softened by plunging it into cold water. Once the copper is cool enough for the artisan to be able to touch it by hand, the "bottom plate" is made.

3. Acid cleaning: After the copper plates are heated, an oxide film forms on their surfaces, turning them black. Most of the oxide film can be washed off with cold water, but to remove all of it, the plates need to be soaked in a 10% solution of dilute sulfuric acid.

4. Striking: The treated copper plate (or part of it) is placed on a special wooden block and struck along the border between the bottom and sides of the product, using the irregular shape of the block to shape the copper. Through this, the edges of the flat plate are raised and the product becomes three-dimensional.

As copper becomes denser and harder the more times you strike it, it might be necessary to anneal (soften) it a few times during this process.

5. Shaping: As we mentioned before, “tsuiki” means “to shape with a hammer or mallet.” This is that step. A half-finished copper plate is placed on the toriguchi (or ategane) shaping iron and then struck with a mallet at a steady rhythm while being slowly turned with the other hand.

6. Final finishes: The above steps use a wooden mallet to shape the metal. However, this step uses an iron hammer to add fine adjustments and decorations to the surface of the copperware. When the surface of the finished product is struck uniformly with the hammer, it creates a nice, even surface. The more the surface of the copperware is struck, the shinier it becomes, so patient and regular hammering is necessary.

The Wide Variety of Copperware Products

Copper crafts have a long history in Japan, but the techniques behind them have changed over time. There are many “ryotei” (traditional Japanese restaurants) in Oku-Asakusa, which, in the old days, used traditional charcoal braziers called "hibachi" during winter to keep their guests warm. When Dogindoki was still starting out, the company mainly made "otoshi" copper containers for putting ashes in the braziers used by these restaurants. In the summer, when the demand for hibachi decreased, they made copper "tamagoyaki" omelet pans and teapots.

As time went on, restaurants started to use the traditional hibachi braziers less and less. In response to this, Dogindoki gradually shifted its production to other cooking utensils. Nowadays, the shop mainly produces copper tamagoyaki pans during the winter months. Hoshino, who is a big coffee drinker, also makes copper coffee pots and mugs, as well as teacups, in the summer. He says that Chinese customers often buy copper teapots because of their tea-drinking culture, while Western customers often buy mugs and ginger graters. These products are small, sturdy, and rust-resistant, making them great souvenirs or presents.

Do Omelets Made in Copper Cookware Taste Better?

Before the interview, I’d heard that Hoshino’s omelet pans were extremely popular. I was very curious about the differences between a copper pan and a typical stainless steel or Teflon omelet pan. According to Hoshino, copper pans have excellent heat conductivity and high heat storage capacity, so when you cook with them, the heat gets applied evenly to the entire egg mixture. Copper pans also get hot faster, so if you start rolling the omelet little by little when the eggs are half-cooked, they should be heated through by the time you’re finished. This is why the natural flavors of the eggs or the dashi broth used in tamagoyaki omelets are not lost. In other words, copper pans make it possible to fry thick yet soft and fluffy omelets that also cut beautifully.

How to Care for Copperware

Many people who acquire high-quality, artisanal copperware often wonder how to care for it so they can keep using it for years to come. According to Hoshino, caring for copperware is very simple. First, when you use it for the first time, simply wash it with a neutral detergent and a soft sponge. After that, wash it the same way after each use, wipe it down, and dry it in a well-ventilated place. The longer you use a piece of copperware, the more the surface of the copper will oxidize (sulfurize) and discolorize or even turn black. But that is all perfectly normal so there is no need to worry.

When using copperware directly over fire, please take care to not heat it up completely empty or to allow the temperature to drop suddenly. To prevent rusting, it’s best to not expose copperware to salts and acidic substances for prolonged periods of time. Copper is also not suitable for use on induction stoves or in microwaves or ovens. If you take good care of your copper pots and pans, they can last for 40 years or more.

Beautiful Copperware That Spans Centuries

Japan has a long history with copper products, which are both traditional crafts as well as everyday utensils. Copper has many uses, and while it most commonly serves as material for stewpots, omelet pans, and teapots, it can also be used to make teacups, ginger graters, and other tableware. So the next time you’re in Tokyo, be sure to visit Dogindoki to look for your new favorite utensil and to experience the alluring magic of copperware.

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