Unshu Soroban

Beads that ring

The beads are the heart of a soroban: a good one moves smoothly and rings with a clear, high sound. Unshu makers finish the bead holes and bamboo rods with great care, so the abacus gets easier to use the longer you use it. Yokota makes about 70% of Japan's soroban. It is made in Okuizumo in Shimane.

Wood that will not warp

• Beads are cut from woods such as birch, boxwood, isu or ebony.
• Rods are smoke-seasoned susudake bamboo; frames are ebony.
• Every material is chosen with care and dried thoroughly so it will not warp.
• Beads are turned on a lathe, a tool perfected by a Yokota craftsman that made mass production possible.

Iron towns and peddlers

Yokota was a land of tatara iron making, where peddlers came and went. In the late Edo period a carpenter in Nita, copying an abacus made in Hiroshima, crafted a fine soroban from local oak, plum and bamboo. A Yokota craftsman then perfected a hand-turned lathe for beads, output soared, and people began to say 'for soroban, it's Unshu.' Traders carried them with seafood as far as Kanto and Tohoku.