The Japanese eliminated one bead each from the upper and lower deck in each column of the Chinese abacus, because these beads are redundent. That makes the Japanese soroban more like the Roman abacus. The soroban is about 3 inches tall. The beans on a soroban are usually double cone shape. |
The Japanese eliminated one bead each from the upper and lower deck in each column of the Chinese abacus, because these beads are redundent. That makes the Japanese soroban (十露盤) more like the Roman abacus. The soroban is about 3 inches tall. The beans on a soroban are usually double cone shape. |