War is a question of vital importance to the state, a matter of life and death, the road to survival or ruin. Hence, it is a subject which calls for careful study.
To assess the outcome of a war, we need to examine the belligerent parties and compare them in terms of the following five fundamental factors:
The first is the way (dao); the second, heaven (tian); the third, earth (di); the fourth, command (jiang); and the fifth, rules and regulations (fa).
By “the way”, I mean moral influence, or that which causes the people to think in line with their sovereign so that they will follow him through every vicissitude, whether to live or to die, without fear of mortal peril.
By “heaven”, I mean the effects of night and day, of good and bad weather, of winter’s cold and summer’s heat; in short, the conduct of military operations in accordance with the changes of natural forces.
By “earth”, I mean distance, whether it is great or small; the terrain, whether it is treacherous or secure; the land, whether it is open or constricted; and the place, whether it portends life or death.
By “command”, I mean the wisdom, trustworthiness, benevolence, courage and firmness of the commander.
By “rules and regulations”, I mean the principles guiding the organization of army units, the appointment and administration of officers and the management of military supplies and expenditures.
There is no general who has not heard of these five factors. Yet it is he who masters them that wins and he who does not that loses. Therefore, when assessing the outcome of a war, compare the two sides in terms of the above factors and appraise the situation accordingly.
Find out which sovereign possesses more moral influence, which general is more capable, which side has the advantages of heaven and earth, which army is better disciplined, whose troops are better armed and trained, which command is more impartial in meting out rewards and punishments, and I will be able to forecast which side will be victorious.
The general who employs my assessment methods is bound to win; I shall therefore stay with him. The general who does not heed my words will certainly lose; I shall leave him.
Having paid heed to my assessment of the relative advantages and disadvantages, the general must create a favorable strategic situation which will help bring the victory to fruition. By this I mean being flexible and making the most of the advantages to gain the initiative in war.
War is a game of deception. Therefore, feign incapability when in fact capable; feign inactivity when ready to strike; appear to be far away when actually nearby, and vice versa. When the enemy is greedy for gains, hand out a bait to lure him; when he is in disorder, attack and overcome him; when he boasts substantial strength, be doubly prepared against him; and when he is formidable, evade him. If he is given to anger, provoke him. If he is timid and careful, encourage his arrogance. If his forces are rested, wear them down. If he is united as one, divide him. Attack where he is least prepared. Take action when he least expects you.
Herein lies a strategist’s subtlety of command which is impossible to codify in hard-and-fast rules beforehand.
He who makes full assessment of the situation at the prewar council meeting in the temple (translator’s note: an ancient Chinese practice) is more likely to win. He who makes insufficient assessment of the situation at this meeting is less likely to win. This being the case, what chance has he of winning if he makes no assessment at all? With my assessment method, I can forecast who is likely to emerge as victor.