Chapter 6 :
Void and Actuality Generally, he who occupies the field of battle first and awaits his enemy is at ease, and he who comes later to the scene and rushes into the fight is weary. And, therefore, those skilled in war bring the enemy to the field of battle and are not brought there by him. One able to make the enemy come of his own accord does so by offering him some advantage. And one able to stop him from coming does so by preventing him. Thus, when the enemy is at ease, be able to tire him, when well fed, to starve him, when at rest to make him move. Appear at places which he is unable to rescue; move swiftly in a direction where you are least expected. That you may march a thousand li without tiring yourself is because you travel where there is no enemy. To be certain to take what you attack is to attack a place the enemy does not or cannot protect. To be certain to hold what you defend is to defend a place the enemy dares not or is not able to attack. Therefore, against those skilled in attack, the enemy does not know where to defend, and against the experts in defense, the enemy does not know where to attack. How subtle and insubstantial, that the expert leaves no trace. How divinely mysterious, that he is inaudible. Thus, he is master of his enemy's fate. His offensive will be irresistible if he makes for his enemy's weak positions; he cannot be overtaken when he withdraws if he moves swiftly. When I wish o give battle, my enemy, even though protected by high walls and deep moats, cannot help but engage me, for I attack a position he must relieve. When I wish to avoid battle, I may defend myself simply be drawing a line on the ground; the enemy will be unable to attack me because I divert him from going where he wishes. If I am able to determine the enemy's dispositions while, at the same time, I conceal my own, then I can concentrate my forces and his must be divided. And if I concentrate while he divides, I can use my entire strength to attack a fraction of his. Therefore, I will be numerically superior. Then, if I am able to use many to strike few at the selected point, those I deal with will fall into hopeless straits. The enemy must not know where I intend to give battle. For if he does not know where I intend to give battle, he must prepare in a great many places. And when he prepares in a great many places, those I have to fight in will be few. For if he prepares to the front, his rear will be weak, and if to the rear, his front will be fragile. If he strengthens his left, his right will be vulnerable, and if his right, there will be few troops on his left. And when he sends troops everywhere, he will be weak everywhere. Numerical weakness comes from having to guard against possible attacks; numerical strength from forcing the enemy to make these preparations against us. If one knows where and when a battle will be fought, his troops can march a thousand li and meet on the field. But if one knows neither the battleground nor the day of battle, the left will be unable to aid the right and the right will be unable to aid the left, and the van will be unable to support the rear and the rear, the van. How much more is this so when separated by several tens of li or, indeed, be even a few! Although I estimate the troops of Yue as many, of what benefit is this superiority with respect to the outcome of war? Thus, I say that victory can be achieved. For even if the enemy is numerically stronger, I can prevent him from engaging. Therefore, analyze the enemy's plans so that you will know his shortcomings as strong points. Agitate him in order to ascertain the pattern of his movement. Lure him out to reveal his dispositions and ascertain his position. Launch a probing attack in order to learn where his strength is abundant and where deficient. The ultimate in disposing one's troops is to conceal them without ascertainable shape. Then the most penetrating spies cannot pry nor can the wise lay plans against you. It is according to the situations that plans are laid for victory, but the multitude does not comprehend ts. Although everyone can see the outward aspects, none understands how the victory is achieved. Therefore, when a victory is won, one's tactics are not repeated. One should always respond to circumstances in an infinite variety of ways. Now, an army may be likened to water, for just as flowing water avoids the heights and hastens to the lowlands, so an army should avoid strength and strike weakness. And as water shapes its flow in accordance with the ground, so an army manages its victory in accordance with the situation of the enemy. And as water has no constant form, there are in warfare no constant conditions. Thus, one able to win the victory by modifying his tactics in accordance with the enemy situation may be said to be divine. Of the five elements [water, fire, metal, wood, and earth], none is always predominant; of the four seasons, none lasts forever; of the days, some are long and some short, and the moon waxes and wanes. That is also the law of employing troops.