Unshu abacus Photo:Shimane Perfecture

Unshu abacus Unshu soroban

180 handcrafted steps add up to one superb soroban
The rhythmic clack of beads, the sound of craftsmanship


What is Unshu abacus ?

Unshu Soroban are abacuses made in the towns of Nita and Yokota in Nita County, Shimane Prefecture. Even today, the traditional handcraft methods are carefully followed from the inspection of materials through to the completed soroban. The materials are completely natural and little changed over the centuries, mainly birch beads turned from trees grown in Tochigi, Gunma, Saitama, or Iwate Prefecture, or isunoki wood from Kagoshima Prefecture; frames crafted of ebony, Macassar ebony, or specially reinforced plywood; and rods of bamboo or smoke-stained bamboo.
Unshu Soroban are distinguished by their great ease of use; prized attributes include high quality beads that magically stick to the fingers, smooth fast movement and a clear high tone as the beads strike, all indicative of the highest level of craftsmanship. Careful attention to detail and ensuring the accuracy of each natural component, especially the bead shape, earned the Unshu Soroban a reputation for the very best quality.
There are three main types of abacus, which vary in length and size: they are for scholars, for wholesalers, and a portable version for people on the go. With the minimum of simple care, a quick wipe with a soft dry cloth after use, an abacus will offer regular service for generations. Like most wooden items, abacuses do not like high temperatures or humidity, and must be stored in a cool place out of direct sunlight. Although simple, they are delicate and can suffer from water damage, sometimes making them impossible to repair.


Unshu abacus - History Photo:Shimane Perfecture

In 1832, Kichigoro MURAKAMI, a carpenter living in Nita Town, Shimane Prefecture made the first Unshu Soroban from local oak, Japanese apricot, and smoke-stained bamboo by referring to a Hiroshima (Geishu) Soroban as a model.
The Unshu region is also known as a production center of tamahagane (sword steel made by smelting iron sand). With good quality steel tools and an abundance of local natural materials, production flourished and spread across the Unshu region, soon developing into a local industry with increasing production. After World War II, the production process was further mechanized leading to modern mass production.
Nowadays, the role of the abacus has been replaced by computers and electronic calculators; however, even in an increasingly modern society, the humble abacus is still popular across the generations. The movement of hands and fingers when using an abacus stimulates the brain’s central nervous system; it is considered that abacuses help improve being quick on the uptake, and moving the fingers is also helpful for preventing aging. Such discoveries are leading to the re-evaluation of the abacus and its place in modern life and culture.

General Production Process

Unshu abacus - General Production Process Photo:Shimane Perfecture

  1. 1. Making the Beads Japanese box, ebony or rosewood is mainly used for the beads and suitable trees are selected, felled and left to dry before being turned into beads. Although only a simple bead, certain qualities are looked for such as the hardness of the wood, which helps the beads to stick to the fingers.
    Cutting the hard wood through to the final polishing of the typical abacus-shaped beads, requires the skills of experienced craftsmen. Seasoned wood is machine-cut into slices and roughly turned beads are cut out ready for their final shaping.
  2. 2. Making the Rods The rods of the basic popular abacus are mainly made from madake bamboo, while higher quality abacuses use smoke-stained bamboo. The bamboo is cut to length and split and turned into rods before finely polishing to ensure the beads slide smoothly.
  3. 3. Making the Frame The abacus frame is made from either imported hard ebony or reinforced plywood. Wood is roughly cut to length and sized according to the section.
  4. 4. Crossbeam The upper and lower sections of an abacus are separated by a distinctive wooden crossbeam called a hari, which supports and strengthens the rods and frame structure. Firstly, holes are drilled in the hari for the bead rods and then both sides are planed before a fine polish of every face. Then grooves are routed on the front and back faces of the hari in preparation for filling with distinctive white celluloid.
  5. 5. Upper and Lower Frames Holes are drilled on the upper and lower frames for the bead rods before planing all the frame parts (upper, lower, and sides) to a beautiful finish. The frame is now further strengthened by drilling holes to fit the thicker supportive back rods and routing grooves to mount the backboards. After preparing the backboards and bamboo rods, mortise and tenon joints are cut for the frame.
    For the first time, all the pieces of the abacus are temporarily assembled and any fine adjustments are made at this stage. The frame is then disassembled; beads are slid onto the rods, and once again all the components assembled. Unshu Soroban use a technique of drilling holes at strategic locations and inserting aluminum wire pins to further strengthen the integrity of the frame. The completed frame is now given a final light sanding and polishing.
    Unshu Soroban are renowned not only for their practical and durable construction, but also for the natural beauty of their wood grain.

Where to Buy & More Information

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