Bring war material with you from home, but forage on the enemy... use the conquered foe to augment one's own strength.

If the enemy opens the door, you must race in.

The opportunity to secure ourselves against defeat lies in our own hands

All warfare is based on deception. There is no place where espionage is not used. Offer the enemy bait to lure him.

Opportunities multiply as they are seized.

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.

There are three ways in which a ruler can bring misfortune on his army: By commanding the army to advance or to retreat, being ignorant of the fact that it cannot obey. This is called hobbling the army. By attempting to govern an army in the same way as he administers a kingdom, being ignorant of the conditions which obtain in an army. This causes restlessness in the soldier's minds. By employing the officers of his army without discrimination, through ignorance of the military principle of adaptation to circumstances. This shakes the confidence of the soldiers.