"Counting to Ten on the Abacus: The International System of Units and the Algorist Revolution of Commercial Arithmetic in 20th-Century China"

This paper examines how the adoption of the international system of units (SI) radically transformed the use of the abacus in everyday commercial calculations in 20th-Century China. Chinese merchants have traditionally used the “catty (斤，or jin)” and “tael (两，or liang)” as the primary units of weight measurement, with one catty being equal to sixteen taels. However, the successive modernizing regimes of 20th-Century China have repeatedly attempted to align existing weight units with the International System of Units, which operated on a decimal basis. Officially, this process was complete in 1959, when the State Council of the People’s Republic of China decreed that one catty would be equal to ten taels, and that one kilogram would be equal to two catties.
The standardization of the decimal system of weight measurements would prompt a new generation of accountants and managers to experiment with new methods of abacus use that incorporated the principles of formal arithmetic. The abacus had traditionally been an instrument of numeracy for commercial clerks, who only needed to memorize a series of formulas to be able to work with numbers. However, dissatisfied with the long list of formulas of abacus manipulation that needed to be memorized, 20th-Century business professionals sought to develop an approach to abacus use that mirrored the mechanics of written arithmetic calculations. The phasing out of the special abacus formulas for non-decimal systems of weight unit conversions encouraged them to further attempt to eliminate as many existing formulas of rote memorization as possible. This paper will demonstrate that through this new approach, the abacus would become a calculative aid rather than an instrument of numeracy, as mastery of formal arithmetic would now become the precondition for abacus manipulation. This entailed decisive changes in the professional lives of 20th-century business clerks, for whom numeracy in business was no longer possible without knowledge of formal arithmetic.