Tsubame copperware is One of the few traditional copper crafts in Japan
Tsubame hammered copperware is made by hammering a sheet of copper into a shape. The industry originated in the Tsubame area, where copper mines were booming during the Edo period (1603-1868), and was designated a traditional craft by the Minister of International Trade and Industry in 1981.
What makes copperware Tsubame copperware?
The craftsman selects a particular type of tool according to the place where it is to be struck and the shape to be made, and finishes it by using about 20 different tools. Although the surface is bumpy, it has an amazingly smooth and beautiful luster, and the aging of the copper material gives it an indescribable texture as it is used over the years. The beauty of this product is that the hue of light changes depending on the angle from which it is viewed. Various daily necessities such as kettles, teapots, and frying pans are produced from the beauty of form created from a single sheet of plate.
Copper’s thermal conductivity is approximately twice that of aluminum, five times that of iron, and 25 times that of stainless steel, making it much easier to heat than other materials. It is also known as a material with high corrosion resistance and sterilizing properties. Recently, its high thermal conductivity has been used not only for kettles and teapots, but also for pots, pans, teacups, beer cups, and coffee drippers. Furthermore, its beautiful texture has led to its use in various household items such as business card holders and shoehorns.
One of the charms of this technique is that each workshop and craftsman has its own unique shape and coloring, even if the pieces are used for the same purpose. For example, “Xuande-iro,” a vivid maple leaf color reminiscent of sunset, “Shigokini-iro,” a purplish gold color, and “Gin-iro,” a refined silver color with a hint of peach, which have been handed down at Tamagawa-do for generations, are examples of this. Furthermore, the more Tsubame hammered copperware is used, the more it gains luster and changes to its own unique old color.
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| Source: Niigata Chokuso Keikaku |
History
Tsubame City in Niigata Prefecture, famous for its metalworking, is said to have begun its history around the early Edo period (1603-1867) with the production of Japanese nails. Then, around the middle of the Edo period, craftsmen from Sendai visited Tsubame City and taught Tsubame how to make hammered copperware, which was the origin of Tsubame copperware. The forging technique introduced at that time has been handed down for more than 200 years.
Tsubame is currently the only production for traditional hammered copperware in Japan, and the reason for its development is the high quality copper ore that can be extracted from the nearby Yahiko Mountain. Tsubame copperware began with the production of kettles, but in the Meiji period (1868-1912), it moved beyond daily necessities, incorporating engraving techniques and adding elements of arts and crafts.
Copperware that develops its flavor over time, such as kyusu (teapots), vases, and works of art, have long been cherished and have become indispensable products in daily life. In 1894, the company presented a vase to Emperor Meiji.
Manufacturing method & Process
1. Hammering
The production process of hammered copperware differs depending on the form of the copperware to be made. Here, we will explain the basic process based on a popular hot-water pot product. There are four processes: copper sheet molding, sheet metal forming, decorative processing, and finishing. The first process is to cut the copper sheet to a predetermined size as a molding process.
The first step of the forming process is to start with the side portion. The side portion is placed against a special wooden stand and struck with a mallet. The dents in the wooden stand have important meanings, and different dents are used for different areas, such as the sides and the spout. Also, depending on the hardness and expansion/contraction of the copper plate, it is necessary to consider the strength and subtle angle of the strike. This is a difficult process that requires the skill and experience of a craftsman.
2. Striking and Shrinking
The next step is the hammering and shrinking process, in which the finished copper sheet is hung on a metal fitting called torikuchi. The metal fittings, also called “atagane,” are used in a variety of ways depending on the finished product, and are inserted into the raised board of the stand made of zelkova wood. In order to make the mouth part of a hot-water pot, it is necessary to tap it over and over again, which requires patience and concentration.
3. Annealing
Since the piece gradually becomes harder as it continues to be pounded, it is once softened in a furnace. The temperature is heated to about 650 degrees Celsius to soften it. The process is then repeated until the piece is completed.
4. Molding
This is the forming process to shape the
product. Unevenness and distortion that may occur throughout the entire piece
are adjusted and balanced to create a beautiful shape. The more the gold is
beaten, the more luster is produced on the surface.
5. Engraving
Once the shape is created, the surface is
worked. Using a tool called a “tagane,” a fine pattern is drawn,
engraved, and hammered out. In some cases, inlays of gold or silver are used to
decorate the surface. Through the process of metal carving, it is possible to
create brightness and splendor in a product that was previously only
copper-colored.
6. Colored Finish
Finally, to enhance the texture of the gold skin, it is changed by dipping it in a solution. There are two types of this coloring method. In the black coloring method, tin is applied, then baked at 800°C and beaten. The finished copperware is then boiled in a liquid mixture of greenish blue and copper sulfate to give it a tasteful blackish-purple color.
In the red group, the bronze is stewed for several hours longer than in the black group. The black color can produce a color called kinko-iro, and the red color can produce a color called xuande-iro. The products produced by Tsubame Hammering Copperware have a unique beauty due to the repeated process of hammering and shrinking from a single copper sheet. For craftsmen who carry on the traditional techniques, the hammering technique is the lifeblood of Tsubame Copperware, so craftsmen must also be skilled in their work.
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| Source: Guru Navi |
