“While heading the profit of my counsel, avail yourself also of any helpful circumstances over and beyond the ordinary rules.
17. According as circumstances are favorable, one should modify one's plans.
18. All warfare is based on deception.
19. Hence, when able to attack, we must seem unable; when using our forces, we must seem inactive; when we are near, we must make the enemy believe we are far away; when far away, we must make him believe we are near.”