Unshu abacus Photo:Shimane Perfecture

Unshu abacus Unshu soroban

180 handcrafted steps are needed
to create one superb piece


What is Unshu abacus ?

Unshu soroban is a type of abacus made in the towns of Nita and Yokota in Nita rural district, Shimane prefecture. The traditional handcraft methods are still upheld and the abacus is produced with care from selecting the materials to the end. The materials are all completely natural and birches mainly come from Tochigi, Gunma, Saitama, or Iwate prefecture or distylium racemosum from Kagoshima prefecture are used to produce the beads. The frame is crafted with ebony, Macassar ebony or special reinforced plywood, while the rods are crafted with processed bamboo or soot colored bamboo.
Unshu abacus are distinguished by their prized attributes that include fine quality beads that adhere to the finger moves. Only a high craftsmanship can produce such smooth strikes of beads following the fast finger movement with the clear high tone of strike hits. Unshu abacus is respected for its finest qualities in every detail including the shape of beads, uniformed hole sizes, and the accurate interval between the beads and axles. There are three types of abacus including scholar use, wholesaler use and portable ones which vary in length and size.
It can be used for many years by only taking minimum care of it such as giving it a quick wipe with a soft dry cloth after use. Like most wooden items, the abacuses is not suitable for high temperatures and humid environment, they require to be stored in a cool place and out of direct sunlight. As it is a delicate product, an abacus with serious water damage might not be repairable.


Unshu abacus - History Photo:Shimane Perfecture

In 1832, Kichigoro MURAKAMI (1787-1876) a carpenter living in the town of Nita, Shimane prefecture made the first Unshu abacus from local oak, Japanese apricot, and smoke stained bamboo by referring to a Geishu abacus as a model.
The Unshu region is also known as a production district of tamahagane, which is the steel material of sword made by smelting iron sand.
The Unshu region was blessed with the suitable kind of natural materials and quality steel tools, which helped the abacus production industry to flourish. The production volume has increased since the production process has been published. Moreover, the production process was further mechanized and led to modern mass production after World War II (939-1945).
Nowadays, the role of the abacus has been replaced by computers and electronic calculators. However, the humble abacus is still favored across the generations although the modernization and mechanization are ongoing.
It is said that the hand and finger strokes on abacus stimulate the central nervous system of the brain and encourages brain work. Furthermore, it is considered to be a supportive tool that prevents aging and improves the uptake. Such discoveries are leading to the re-evaluation of the abacus and it is referred to as a part of Japanese culture.

General Production Process

Unshu abacus - General Production Process Photo:Shimane Perfecture

  1. 1. Beads production The suitable timber for the abacus beads are chosen and thoroughly dried to get ready to be shaped. The texture of timber for the beads should have the proper hardness and gentle touch that follows the finger strokes. Timber used for beads is mainly Japanese box, ebony or rosewood. It requires a high craftsmanship to cut the hard timber into smaller pieces through the shaping and polishing of special shaped abacus beads.
    To start up the process, the machine cut is proceeded on the seasoned timber to slice the timber. Then careful shaping work is carried on to shape a final sphere shape after the rough sphere is cut out of the wood piece
  2. 2. Rods making The rods of the basic popular abacus are mainly made from phyllostachys bambusoides (Japanese timber bamboo), while higher grade abacuses use smoke stained bamboo. The bamboo is cut to length and further cut into smaller pieces and shaped to the beads. A fine polish is given to the beads for ensuring the smooth moves.
  3. 3. Frame assembling The abacus frame is made from either imported hard ebony or reinforced plywood. The woods are roughly cut to the length and size. Then the roughly shaped pieces receive further refinements.
  4. 4. Frame strenthening The upper and lower frame of an abacus are separated by a distinctive wooden crossbeam called hari, which supports and strengthens the rods and frame structure. Firstly, holes are drilled in the crossbeam for the bead rods and then both sides are planed before a fine polish is given on every side. Then, grooves are routed on the front and back sides of the crossbeam in the 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 including the sides to a beautiful finish. The frame is now further strengthened by drilling holes to fit the thicker supportive axle and back rods. After preparing the backboards, the routing grooves are made to mount the backboards and then the mortises are drilled on the beams. Then the grooves are filled with the distinctive white celluloid.
    The process moves onto the tenon joints making for assembling the frames. First of all, all the pieces of the abacus are temporarily assembled and any fine adjustments are made before the final assemble. Then the temporary assembled frame is disassembled. The beads are slid onto the rods and all the components are assembled back. Unshu abacus use a technique of drilling the joint 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 abacus is renowned not only for their practical and durable construction, but also for the natural beauty of their wood grain.

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