そろばん

The soroban (算盤, そろばん^?, counting tray) is an abacus developed in Japan. It is derived from the suanpan, imported from China to Japan around 1600.^[1] Like the suanpan, the soroban is still used today, despite the proliferation of practical and affordable pocketelectronic calculators.


http://en.wikipedia.org/wiki/Soroban