The good fighters of old first put themselves beyond the possibility of defeat, and then waited for an opportunity of defeating the enemy.
To secure ourselves against defeat lies in our own hands, but the opportunity of defeating the enemy is provided by the enemy himself. Thus, the good fighter is able to secure himself against defeat, but cannot make certain of defeating the enemy. Hence the saying:
One may know how to conquer without being able to do it.
If you cannot conquer then use defensive tactics; if you can conquer take the offensive. Standing on the defensive indicates insufficient strength; attacking, a superabundance of strength¹ [1An alternative meaning for this last is that taking a defensive posture allows your strength to be sufficient.].
The general who is skilled in defense hides in the most secret recesses of the earth; he who is skilled in attack flashes forth from the topmost heights of heaven. Thus on the one hand we have ability to protect ourselves; on the other, a victory that is complete.
To see victory only when it is within the ken² [2Ken means understanding.] of the common herd is not the acme of excellence. Neither is it the acme of excellence if you fight and conquer and the whole Empire says, "Well done!"³ [3We should take this as meaning that excellence isn't winning when any other general could have done so, and neither is excellence the product of praise. To be deemed excellent we must do something difficult. This theme is carried into the next paragraph.]
To lift an autumn hair is no sign of great strength; to see the sun and moon is no sign of sharp sight; to hear the noise of thunder is no sign of a quick ear. What the ancients called a clever fighter is one who not only wins, but excels in winning with ease. Hence his victories bring him neither reputation for wisdom nor credit for courage. He wins his battles by making no mistakes. Making no mistakes is what establishes the certainty of victory, for it means conquering an enemy that is already defeated. Hence the skillful fighter puts himself into a position which makes defeat impossible, and does not miss the moment for defeating the enemy. Thus it is that in war the victorious strategist only seeks battle after the victory has been won, whereas he who is destined to defeat first fights and afterwards looks for victory.
The consummate leader cultivates the moral law, and strictly adheres to method and discipline; thus it is in his power to control success.
In respect of military method, we have, firstly, Surveying⁴ [4Giles uses the word measurement here. Intelligence is probably the most apt word (in its modern usage), but I felt that wouldn't go as well with the character of the text.]; secondly, Estimation of quantity; thirdly, Calculation; fourthly, Balancing of chances; fifthly, Victory.
Surveying owes its existence to the Earth; Estimation of quantity to Serveying; Calculation to Estimation of quantity; Balancing of chances to Calculation; and Victory to Balancing of chances.
A victorious army opposed to a routed one is as a pound's weight placed in the scale against a single grain. The onrush of a conquering force is like the bursting of pent-up waters into a chasm a thousand fathoms deep.