Japanese hammer raising (tsuiki) is a traditional Japanese metalworking technique where metal is hammered into shape, particularly using copper or tin as materials, with each piece being finished by hand.
Its rugged yet refined beauty and the deepening patina that develops with long use have captivated many craft enthusiasts and collectors.
This article provides a detailed explanation of the Japanese hammer raising manufacturing process, representative products, points to consider when selecting pieces, and maintenance methods to preserve their beauty for a long time. Please use this as a guide to finding your perfect piece while exploring the depth of metal craftsmanship.
Table of Contents
What is Japanese Hammer Raising? Origins and Differences from Forging and Casting
Japanese hammer raising (tsuiki) is a traditional Japanese metalworking technique where a single sheet of metal is hammered into a three-dimensional vessel. Its origins date back to the early Edo period, and as a craft that fuses skilled craftsmanship with aesthetic sensibility, it continues to be highly valued in modern times. Below, we explain in detail the history, characteristics, and contemporary value of Japanese hammer raising.
The Roots of Copper Japanese Hammer Raising and Artisan Culture That Flourished in the Mid-Edo Period
While the technique of Japanese hammer raising itself dates back to medieval metalwork used for armor and Buddhist implements, it was established as an industry in the Tsubame (Sanjo) region during the mid-Edo period in the late 17th to early 18th century. The combination of hammering techniques brought from Sendai and copper resources from the Yahiko mountain system led to its spread as a side business during the agricultural off-season for making kettles and pots. By the end of the Edo period, it had grown into a major local industry even listed in the “Echigo Products Ranking.”
In 1981, “Tsubame Hammer Raised Copperware” was designated as a national traditional craft. Today, traditional craftsmen in Tsubame-Sanjo continue to shape and color pieces through repeated firing (annealing) and water cooling, creating deep luster and varied patterns through mirror polishing and sulfide coloring.
What’s the Difference Between Forging, Casting, and Hammer Raising?
In metalwork, there are techniques such as forging (tankin) and casting (chukin), but Japanese hammer raising has different characteristics. Forging is a technique where metal is hammered to shape, and casting is a technique where molten metal is poured into a mold. Japanese hammer raising, on the other hand, is a technique where a single sheet of metal is hammered to create a three-dimensional shape, characterized particularly by unique patterns called “tsuchime” (hammer marks).
Tsuchime are patterns created when an artisan hammers metal, giving a warmth and individuality unique to handwork. These patterns differ with each product, and no two are exactly alike. Therefore, hammer raised products have high value as one-of-a-kind pieces, enhancing their appeal as craft items.
Contemporary Value in Barware and Interior Design
In recent years, products using Japanese hammer raising techniques have attracted attention as barware and interior items. For example, copper tumblers and cocktail shakers excel in cooling properties and antibacterial qualities, making them valuable for professional bartenders and restaurants.
Additionally, the beautiful hammer mark patterns create a sophisticated atmosphere, making them popular as household glasses and plates. Furthermore, lighting fixtures and flower vases that utilize hammer raising techniques have emerged, with traditional crafts being reevaluated in ways that blend into contemporary lifestyles.
These products are highly regarded both domestically and internationally as a fusion of high quality through artisanal handwork and beautiful design. Japanese hammer raising is a traditional craft that Japan should be proud of, born from a long history and artisanal technique. Understanding its appeal can bring color and richness to everyday life.
The Process of Japanese Hammer Raising from Material Selection to Finishing
This technique of creating three-dimensional vessels from a single sheet of metal requires the skilled craftsmanship of artisans at every stage, from material selection to final finishing. Here, we explain the process of Japanese hammer raising from material selection to finishing.
Copper and Brass Sheet Materials and the Importance of Annealing
The main materials used in Japanese hammer raising are copper and brass. These metals combine workability with beautiful finishing and are commonly used in traditional crafts.
Copper
Soft and easy to work with, but prone to oxidation, requiring careful finishing and storage
Brass
An alloy of copper and zinc, harder than copper with a distinctive luster
During processing, metal hardens with hammering. This is called “work hardening.”
As work hardening progresses, the metal becomes more prone to cracking, so “annealing” must be performed at appropriate times to soften the metal again.
Annealing Process
- Heat the metal until it turns red.
- Then cool it in air or quench it in water.
This process releases internal stress in the metal, making it workable again.
Hammering, Drawing, and Leveling Techniques to Create Curved Surfaces
The appeal of Japanese hammer raising lies in the unique texture and shape created by hammering metal. Through the following processes, a flat metal sheet transforms into a vessel with beautiful curved surfaces.
Spreading
Hammering the entire metal to spread it to a uniform thickness.
Drawing
Hammering the center of the metal to create depth and three-dimensional shape.
Leveling
Smoothing out surface irregularities to create a smooth curved surface.
In these processes, different tools such as hammers and stakes are used, adjusting force and angle as the work progresses. This requires the experience and intuition of the artisan.
Oxide Film Coloring and Smoking Finish Determine the Final Luster and Color
In the final process of Japanese hammer raising, finishing techniques give the metal surface unique colors and luster. This enhances both the beauty and durability of the work.
Oxide Film Coloring
Heating the metal surface to form an oxide film creates various colors through light interference. This technique is used to add color without painting or dyeing, and is also used with stainless steel.
Smoking Finish
A technique of blackening the metal surface by smoking it with chemicals or smoke containing sulfur components. This creates a subdued texture and antique-like finish.
These finishes greatly influence the final impression of the work, so artisans pay careful attention when performing these tasks.
How to Select Japanese Hammer Raised Copperware and What to Watch For
Japanese hammer raised copperware is a traditional Japanese metal craft loved by many for its beauty and functionality. However, to determine quality and authenticity, not just appearance, several points must be considered.
Below, we explain in detail how to check thickness, center of gravity balance, hammer mark patterns, signature stamps, and certificates.
Japanese Hammer Raised Copperware: Thickness and Center of Gravity Balance Matter, Not Just Appearance
When determining the quality of hammer raised copperware, first pay attention to thickness and center of gravity balance. High-quality copperware has uniform thickness and feels stable when held.
The sound when lightly tapping the bottom is also an important criterion. A clear resonant sound indicates high material density and excellent processing precision. On the other hand, a dull sound or uneven resonance may indicate internal cavities or insufficient processing.
Furthermore, the balance of the center of gravity is important. If you feel an imbalance when lifting it, the shape or thickness may not be uniform. By checking these points, you can discern quality differences that cannot be judged by appearance alone.
How to Read Hammer Mark Patterns (Arare-me, Nashiji-me) and Signature Stamps
The surface of hammer raised copperware features hammer mark (tsuchime) patterns that reflect the artisan’s technique and aesthetic sense. Representative patterns include “arare-me” and “nashiji-me.” Arare-me is a pattern of evenly arranged small dot-like marks that give a delicate impression. Nashiji-me, on the other hand, is characterized by fine irregularities like a pear’s skin, creating a soft luster.
These patterns not only provide decoration but also practical benefits such as slip resistance and improved tactile quality. They are also elements that indicate the artisan’s skill level and style, with subtle differences even in the same pattern.
Additionally, the artist’s signature stamp may be engraved on the bottom or side of the copperware. This is an important clue for confirming the authenticity of the work. Signature stamps include the artist’s name, workshop name, and year of production, which can be used to determine the origin and value of the work.
Pre-Purchase Checklist for Confirming Artist and Origin Certificates
When purchasing hammer raised copperware, checking the following points can help you select a reliable product.
Presence of Artist Certificate
Works by notable artists may come with certificates issued by the artist or their workshop. This can confirm the authenticity and value of the work.
Confirmation of Origin Certificate
Copperware produced in traditional regions such as Tsubame City in Niigata Prefecture or Takaoka City in Toyama Prefecture may come with origin certificates issued by regional craft associations or local governments. This guarantees the product’s origin and quality.
Retailer Reliability
We recommend purchasing from specialty stores handling traditional crafts or trusted online shops. Checking the reputation and reviews of the retailer allows for peace of mind when purchasing.
By keeping these checkpoints in mind, you can select high-quality hammer raised copperware. Also, with proper care after purchase, you can maintain its beauty for a long time.
Japanese Hammer Raising Experience
Tsubame City Tourism Association
The roots of Tsubame, a town of manufacturing, lie in Japanese nail making that was adopted as a side business by farmers during the Edo period.
Feel the passionate spirit of artisans that has been passed down to the present day while touring numerous world-renowned impressive techniques.
*Please contact each company for tours and experiences.
How to Maintain Japanese Hammer Raised Copperware for Long-Term Use
With proper care, hammer raised copperware can maintain its beautiful texture for a long time. It is important to keep in mind the following points, from daily care to specialized repairs.
Daily Care and Cloth Selection to Prevent Verdigris and Discoloration
Copperware may develop verdigris, a blue-green rust on the surface, due to moisture in the air or oils from hands. The following daily care is effective in preventing this.
Wash Immediately After Use
Use a mild detergent and wash gently with a soft sponge. It is important to wipe off moisture immediately after washing.
Ensure Thorough Drying
Remaining moisture can accelerate oxidation. After washing, thoroughly wipe off moisture with a soft cloth and dry in a well-ventilated place.
Use an Appropriate Cloth
Microfiber cloths have fine fibers that can remove dirt without scratching the surface. Regular dry wiping helps prevent surface oxidation.
By performing these care routines daily, you can suppress verdigris formation and maintain the beauty of your copperware.
Examples of Restoration Through Tin Lining and Recoloring
With years of use, the tin lining inside copperware may peel off, or the surface color may change. The following restoration methods can restore these deteriorated items to their beautiful state.
Reapplication of Tin Lining
The tin lining applied to the inside of copperware wears with use. Reapplying tin lining prevents metal exposure and allows for hygienic use.
Recoloring Treatment
If the surface color has changed, recoloring can restore the original beautiful color tone. This process includes reforming the oxide film and smoking finish.
These restoration works are often performed by specialized workshops or artisans and are effective in extending the life of copperware.
When to Seek Professional Repair and Cost Estimates
If your copperware shows the following symptoms, professional repair should be considered.
Water Leakage or Cracks
If water leakage occurs during use or if cracks appear on the surface, prompt repair is necessary.
Handle or Lid Malfunction
If the handle becomes loose or the lid doesn’t close properly, parts replacement or adjustment is needed.
Significant Discoloration or Corrosion
If discoloration or corrosion that cannot be improved with normal care is observed, specialized treatment is required. Repair costs vary depending on the repair content and product condition, but generally fall within the following price ranges:
- Water leak repair: About 12,000 yen and up
- Handle replacement or adjustment: About 7,000 yen and up
- Surface refinishing (such as lacquer application): About 36,000 yen and up
However, since these repairs are performed by specialized workshops or artisans, it is important to get an estimate in advance.
Summary
Japanese hammer raised copperware requires detailed knowledge and attention from material selection through production, selection, and daily maintenance as a traditional craft.
When purchasing, it’s important to confirm artist certificates and origin certificates, and to obtain them from reliable sellers. Daily care such as washing and drying after use helps prevent verdigris and corrosion.
For tin lining peeling or color changes, specialized reprocessing is possible, and it’s reassuring to know repair costs in advance. Japanese hammer raised copperware, which has inherited tradition, holds value that can be loved across generations with correct knowledge and care.
Why not experience the joy of enjoying its charm with your own hands and passing it on to the next generation?
