【Introduction to Traditional Crafts】 ～Takaoka Copperware (Toyama Prefecture)～
2023.01.11 
About Japan's Traditional Crafts
【name】
Takaoka Copperware
【Production area of Takaoka Copperware】
Takaoka City, Toyama Prefecture
【What is Takaoka Copperware?】
Copperware produced around Takaoka City, Toyama Prefecture.
A casting made by pouring molten metal into a mold and solidifying it.
In addition to copper, tin and other metals are used as raw materials.
Bronze ware ranges from small items such as vases to temple bells and large bronze statues.
The Takaoka Daibutsu, one of Japan’s three great Buddha statues, is 16 meters high and is made of Takaoka copperware.
It is said that Takaoka copperware has more than 90% of the national share, and the famous statue of Kinjiro Ninomiya is also made of Takaoka copperware.
Also, many of the temple bells (temple bells) are made in Takaoka, so it may not be an exaggeration to say that most people have seen them.
Actively exporting to overseas, and high quality is highly evaluated by foreign countries.
In February 1975, it was designated as a traditional craft.
【Features of Takaoka Copperware】
There are two main features: casting technology and processing technology.
Casting is done by hand by skilled craftsmen.
Processing techniques include polishing, engraving (carving metal), and inlay (inserting different materials into one material).
These various processing techniques are applied to Takaoka Copperware.
Craftsmen have developed through friendly rivalry, polishing their skills, and merging them.
Takaoka copperware combines not only strength but also delicacy.
In addition, the expression changes with the passage of time, adding weight and depth.
Not only can it be used for a long period of time, such as from parent to child, but you can also enjoy the change in appearance.
【History of Takaoka Copperware】
The origin dates back to about 410 years ago.
In 1609, Toshinaga Maeda, the second lord of the Kaga Domain, entered Takaoka Castle.
As part of its economic policy, in 1611 seven foundries were hired.
This is said to be the root of Takaoka Copperware.
A foundry was built in the present-day Kanaya-cho, Takaoka City, with seven casting masters.
Initially, the company mainly produced iron castings for daily necessities such as farm equipment and cooking utensils.
It is said that the production of copperware began in the 1830s and 1840s.
Compared to iron, copper casting is a material that can be expressed in delicate shapes and has high workability.
By making use of this characteristic, Buddhist altar fittings and works of art have also been made.
In the Meiji era, Takaoka Copperware was exhibited at the World Expositions held in various European countries.
Highly regarded for its Japanese design and high quality, it sparked a Japan boom.
From the Meiji to Taisho eras, tea utensils and ornaments were actively produced, and the name of Takaoka copperware became widely known in Japan.
As a result, demand as a gift has increased, and further development has been achieved to the present.
【Production process of Takaoka Copperware】
①Prototype production
Takaoka copperware is produced by a processing method called “casting”.
Casting is a method of shaping a product by pouring molten metal into a mold.
There are four traditional casting methods for Takaoka lacquerware.
・Double casting method
The oldest technique used to make cylindrical (conical) braziers, tea kettles, temple bells, etc.
・Piece casting method
A technique used to make a wide range of products, from small figurines to large bronze statues.
・Wax type casting method
High-precision techniques such as the shape of a dragon.
・Green casting method
It is suitable for mass production and is a technique developed from Takaoka Copperware.
Prototyping is the creation of prototypes for future products.
After drawing a blueprint of what kind of design to make, craftsmen use materials that are easy to process, such as resin and clay.
②Made with real soil
This is the process of creating the mold.
Since molten metal is poured into the mold, refractory materials (such as foundry sand) are used.
Apply a release agent (a chemical used to smoothly remove from the mold) to the prototype created in the previous process.
After that, the prototype is covered and hardened by piling up paper clay and real clay from above.
Then dry thoroughly.
In some cases, reinforcing bars are inserted into the mold to reinforce it.
③Mold matching
The mold consists of two parts, the “outer mold” and the “core mold”.
The core mold is slightly smaller than the prototype.
Melted metal flows between the outer mold and the core mold, and when dried, it becomes a product.
The thickness of a casting product is determined by the “gap between the outer mold and the core mold”, so it is possible to adjust the thickness even for products of the same shape.
It is said that the more even the thickness and the more even the gaps are, the more beautiful the casting will be.
④Completion of the outer mold
After drying, remove the prototype from the mold, and the outer mold is completed.
⑤Scouring and dissolution
Scouring is the process of removing impurities to increase the purity of the metal.
It also melts solid metals to create “molten metals”.
Molten metal is a molten liquid metal that is used in the next process when it is poured into a mold.
⑥Casting
Casting is the process of pouring molten metal into a mold, using a copper alloy that has been melted to approximately 1150 to 1250 degrees Celsius.
The most important thing in casting is temperature control.
This is because if the temperature is too high, the surface of the casting will become rough after completion, increasing the possibility that the finished product will not be beautiful.
Also, the molten metal itself is very hot, so the craftsmen must be extremely careful not to cause an unexpected accident.
⑦Mold removal
Wait for the copper poured into the mold to cool and harden.
Once solidified, the outer mold and core mold are removed, and the product is taken out.
⑧Finishing (polishing, engraving, inlaying, coloring, etc.)
As the final finishing touches, polishing, engraving, inlaying, and coloring are performed.
・Polishing
Craftsmen may simply polish the surface, but they may also use chemical polishing, which uses corrosive action to eliminate unevenness.
In addition, since the product is made of copper, it can cause corrosion in a relatively short period of time when immersed in acetic acid.
・Metal engraving
Using a tool called a “tagane”, carving the copper surface to create a pattern.
There are dozens of types of chisels, and craftsmen use them properly to create various beautiful patterns.
Castings such as Buddhist altar fittings with metal engraving are called “Karakin castings” and are said to have been created by Takaoka Copperware.
・Inlaid
“Inlay” is a decorative technique in which the surface made of copper is shaved and metal other than copper is inlaid.
Here are three representative examples.
Line inlay → A technique of inlaying gold or silver on the shaved lines
Inlay that is cut and fitted → A technique in which a hole is made in the body surface and then gold or silver is inlaid and brazed
High thickness inlay → A technique to create raised areas on the surface of the product
・Coloring
Coloring is the use of chemicals to add color.
By chemically reacting with chemicals, colors such as “Toku-iro”, “Boiled color”, “Bronze color”, “Baked bronze color” and “Red burnt color” are produced.