Art of War 4.18

It is not easy to distinguish the four terms 度量數稱 very clearly. The first seems to be surveying and measurement of the ground, which enable us to 量 form an estimate of the enemy’s strength, and to 數 make calculations based on the data thus obtained; we are thus led to 稱 a general weighing-up, or comparison of the enemy’s chances with our own; if the latter turn the scale, then 勝 victory ensues. The chief difficulty lies in 數, which some commentators take as a calculation of numbers, thereby making it nearly synonymous with 量. Perhaps 量 is rather a consideration of the enemy’s general position or condition (情 or 形勢), while 數 is the estimate of his numerical strength. On the other hand, Tu Mu defines 數 as 機數, and adds: 强弱已定然後能用機變數也 “the question of relative strength having been settled, we can bring the varied resources of cunning into play.” Ho Shih seconds this interpretation, which is weakened, however, by the fact that 稱 is given as logically consequent on 數; this certainly points to the latter being a calculation of numbers. Of Capt. Calthrop’s version the less said the better.