Yi 1 : A unit of quantity in Chinese, equal to 100 000 000. The yi is used with the wan (10 000) in expressing large numbers, one yi being the same as one wan wan (ten thousand ten-thousands)
Russ Rowlett (Director), How Many? A Dictionary of Units of Measurement, Center for Mathematics and Science Education University of North Carolina, USA 2005. http://www.unc.edu/~rowlett/units/dictA.html, (Unit of Meas and Covr Factors - Amer) {608}