Japanese abacus or soroban, c.1930

Japanese abacus or soraban, c.1930. The Soroban is a derivation of the Chinese Suan Pan and is operated in the same way. This example shows the transition from the Chinese Suan Pan which has 2 beads above the bar and 5 below, to the modern Japanese version which has 1 bead above and 4 below. This type ws used from the late 19th century until the 1930s. the beads above the bar represent 5 units and those below, one unit.