The end and aim of spying in all its five varieties is knowledge of the enemy; and this knowledge can only be derived, in the first instance, from the converted spy. Hence it is essential that the converted spy be treated with the utmost liberality.

Act after having made assessments. The one who first knows the measure of far and near wins - this is the rule of armed struggle.

Hence that general is skilful in attack whose opponent does not know what to defend; and he is skilful in defense whose opponent does not know what to attack.

He will win whose army is animated by the same spirit throughout all its ranks.

If I wish to engage, then the enemy, for all his high ramparts and deep moat, cannot avoid engagement; I attack that which he is obliged to rescue.

If our soldiers are not overburdened with money, it is not because they have a distaste for riches; if their lives are not unduly long, it is not because they are disinclined to longevity.

Too frequent rewards indicate that the general is at the end of his resources; too frequent punishments that he is in acute distress.

For them to perceive the advantage of defeating the enemy, they must also have their rewards.

If, however, you are indulgent, but unable to make your authority felt; kind-hearted, but unable to enforce your commands; and incapable, moreover, of quelling disorder: then your soldiers must be likened to spoilt children; they are useless for any practical purpose.