Did East meet West in 1595? Equal tempered approximations 1595, Peking and Amsterdam or the riddle of the abacus and logarithms. Both Tsai‐yu and Stevin set down the mathematical figures for equal temperament. Tsai‐yu calculated the 12th root of 2 by means of the abacus, carefully computing the appropriate root for each note separately—correct to nine decimals. Stevin's calculations on the other hand, finding 11 mean‐proportional parts between 2 and 1, were based upon the 45th proposition of his French arithmetic.