Unshu Abacus is a traditional craft helpful for education

Unshu abacus, a calculator that supported Japanese commerce

Unshu Abacus is an abacus made in Nita-cho and Yokota-cho, Nita-gun, Shimane Prefecture.

*An abacus is a kind of calculation aid, in which beads pierced with a skewer are moved to represent numbers by their positions and aid in calculation. In Japan, the word abacus is sometimes used to refer to all calculation aids using beads.

The abacus is considered to be very good for the brain. Some studies have shown that people who learned abacus as children are better at mathematical and logical thinking.

Unshu abacuses are still handmade and made with great care, including careful selection of materials. The raw materials used for the beads are mainly birch from Tochigi, Gunma, Saitama, and Iwate  prefectures, and oak from Kagoshima prefecture. Ebony, striped ebony, and specially treated tempered wood are used for the frames, and processed bamboo and sooty bamboo are used for the beads’ girders.

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History of Unshu Abacus

 The Unshu abacus was first made in 1832 by Murakami Kichigoro (photo), a carpenter from Nita-machi, Shimane Prefecture, using local oak, plum, and sooty bamboo as carpenters’ tools, based on the abacus made in Hiroshima (Geishu).

 The Unshu region produced tama-hagane (tama steel), which is used to make Japanese swords, and high-quality blades that could sharpen the hard wood used to make beads, which seems to have been a factor in abacus production taking root in the region.　Furthermore, when the manufacturing method was opened to the public, production increased and became the foundation of the local industry.

After World War II, the manufacturing process was mechanized and mass production began, but in 1985, the abacus became a traditional craft designated by the Minister of International Tradeand Industry (now the Ministry of Economy, Trade and Industry) in order to preserve the handmade manufacturing method.

Unshu Abacus Manufacturing Method

The manufacturing process is divided into several parts.

1. Manufacturing process of “Jade”

After selecting trees suitable for abacus beads and drying the logs sufficiently, abacus beads are shaved. The material used for the abacus ball must have a hardness and a surface that is comfortable to the fingers. Mainly boxwood, ebony, and rosewood are used for abacus balls.

Cutting the hard wood and finally polishing it into the unique shape of the abacus ball requires a skilled craftsman’s technique. In order to make a ball shape, the logs are first cut into round slices by using a machine. After the wood is punched out of the slices, it is carefully shaved one by one into the shape of a ball.

2. Manufacturing process of the shaft

The shaft of an abacus is mainly made of madake (a kind of bamboo) for popular abacuses, while sooty bamboo is used for high-end abacuses. Madake is cut to the size of the abacus, split into smaller pieces, and finished with a delicate rounded and polished finish so that the balls move well.

3. Manufacturing process of the frame

Imported hard ebony or laminated reinforced wood is used for the frame of the abacus. After the wood is cut into large pieces, it is cut to size, and each section must be processed accordingly, such as up, down, left, and right. After being cut into small pieces, they are carefully processed into boards that match each part of the frame.

Shimane prefecture

4. Nakasan

After drilling a hole through which the axis of an abacus can pass, both sides of the board are shaved. The top and bottom surfaces, front and back surfaces, and other details need to be polished and finished.

5. Upper and lower frames

After drilling holes in the top and bottom frame boards, the top, bottom, left, and right frame boards are shaved with a planer to clean the surfaces. The planer is a tool used to shave the wood and create a smooth and beautiful finish on the wood surface. A hole is made for the shaft and back stick, and a groove is made for the back board. Once the backing board is made by removing material from the board for the backing board, the next step is to make holes in the board called hari, which is inserted between the upper and lower frames. A hole is made for the bamboo shaft to pass through, and a groove is carved in the hari and filled with celluloid. After the preparation of the bamboo shaft is finished, the next step is to make the “Hoso” for the combination of the frames.

After the work of putting the balls into the shaft, the lower and right frames, the backing plate, and the backing rod are installed one after another. It is necessary to drill holes in the upper and lower frames for the back stick stopper, eye bamboo stopper, and sumi stopper, and stick aluminum wires to make a sturdy abacus.

The frame, which is the place where the hand grips the abacus when it is used and where the beauty of the grain of the abacus appears, is carefully polished, and the wire is cut and filed. The abacus is then carefully polished with sandpaper to create a practical and beautiful abacus with a shiny appearance.

SHIKI NO BI

Key point

The production of Unshu abacus involves a total of 187 processes. Since almost all abacuses are made by hand by a single craftsman, each abacus is engraved with the craftsman’s name. Unshu abacuses are truly masterpieces. The beads have an excellent movement when plucked, and the plucked beads produce a clear and high sound. It is a traditional Japanese craft that is useful for children’s intellectual education and for maintaining cognitive function in old age.

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