The abacus, a device to perform the four basic calculations (addition, subtraction, multiplication and division), is one of the oldest inventions. In a generic way the word is used for a calculation board or just a clean area of sand on which objects such as pebbles could be laid out or numbers written and erased. In that form it was in use in Babylon before 1100 BC, after the introduction of the place-value number system. Its name is thought to derive from the Semitic word abaq (dust).
The abacus was further developed into a board with separation lines for the positions of the numerals. In that form it was in universal use in Europe in the Middle Ages, as well as in the Arab world and in Asia. It reached Japan in the 16th century.
In another form, shown above, beads are strung on wires or rods. This is the form in which the abacus is still in use in the Middle East, China, and Japan, and with which the word abacus is usually associated today.
On the 12th of November 1945, three months after the USA had dropped a nuclear bomb on Hiroshima on 6 August and another one on Nagasaki on 9 August, the army magazine Stars and Stripes organized a competition between the soroban (the Japanese version of the abacus) and the electronic calculator to demonstrate western superiority. Kioshi Matsusaki, the best soroban operator of the Japanese postal service, was set against Thomas Nathan Woods, soldier of the 240th finance unit of General McArthur's headquarters in Japan and the best operator of the desk calculator. Both were given the same number of tasks in the four basic calculations and several mixed calculations.
Matsusaki came out as the winner in addition, subtraction, division and mixed operations; he was defeated in multiplication. The final result was 4:1 for the abacus. Further development of the electronic calculator will not change this result because the speed of calculation is determined by the human ability to key in the numbers, not by the speed of the calculator.
The abacus is particularly good for bookkeeping. The introduction of cash registers with bar code readers, which automate the process of tracking warehouse supplies and reordering goods, greatly reduces the usefulness of the abacus in commerce. But it will continue as an auxiliary calculation tool equivalent to the electronic calculator, which is not faster or more accurate and requires batteries.