Banshu Soroban

A wooden work of art

Banshu soroban use hard, heavy natural woods: beads of birch or boxwood and frames of woods such as ebony. Put together with delicate traditional joints, they are easy to use, the beads flick crisply, and the polished finish makes each one a piece of wooden art. Around 1960 Ono alone made 3.6 million a year in 350 workshops, the most in Japan. It is made in Ono, Kasai, Miki, Kakogawa and Kato in Hyogo.

Pins and polish

• Wood is chosen and dried well, then beads are turned, bamboo rods drawn and frame timber sawn.
• The centre bar, frame and back board are made, beads are threaded on the rods and the frame is assembled.
• Any warp is corrected, and tiny holes are drilled through the frame so pins can lock the bamboo rods in place.
• It is polished with eight grades of sandpaper, horsetail and muku leaves, and rubbed with natural white wax.

Learned in exile

The soroban reached Otsu from China by way of Nagasaki at the end of the Muromachi period. When Toyotomi Hideyoshi besieged Miki Castle, townspeople who fled to Otsu learned to make soroban there, and began making them when they came home. Demand fell after calculators arrived, but makers still receive orders from abacus teachers and accountants across Japan.