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

When the enemy is at ease, be able to weary him; when well fed, to starve him; when at rest, to make him move. Appear at places to which he must hasten; move swiftly where he does not expect you.

Attack him where he is unprepared, appear where you are not expected.

Who can determine where one ends and the other begins?

He who is prudent and lies in wait for an enemy who is not, will be victorious.

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.

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.