Master Sun says, when choosing positions and taking on the enemy, stay close to valleys when crossing mountains. Set up camp high and face the open. Never fight uphill. Keep your distance when crossing rivers. Do not fight an enemy in a river, but let half of his troops cross first. Occupy high ground, face the open and do not go close to the river. Do not attack against the flow of the water.
For every terrain there is a Way to cross it. For example, having the high ground in battle is considered a Yang position of strength. Yet, the valleys have water and more resources, so while the general should fight downhill, he does not want to cut himself off on the mountain peaks. Every position comes with such considerations, and the various approaches are labeled according to Yin and Yang. This helps to find the path of least resistance. For example, attacking against the flow of water will cause the men to tire quickly—positioning them upstream to fight an enemy downstream harnesses the potential energy of the situation to the general’s advantage.
Cross salt marshes rapidly. Never tarry. Stay near trees and grasses if you must fight here. On level ground, take easy terrain. Keep high ground behind you and to the right. Keep death in front and life behind you. By following these rules, the Yellow Emperor defeated the Four Emperors.
Sun gives specific advice for each type of terrain—displaying his deep experience of warfare. Indeed, these rules are long-held, well-proven methods, as suggested by the reference to the mythological Yellow Emperor. He is often referred to in ancient texts as a teacher who conferred various knowledge to ancestral Chinese leaders.
Armies love high ground (Yang) and avoid the low (Yin). To survive and thrive, take the high ground, and you will win. Use the lie of the land to your benefit. If a river is swollen with rain water, let it subside before you cross. If you come to hellish terrain, get out as quickly as you can. Keep away and do not enter. Let the enemy go there and have them at his rear. If you must march through hard to pass terrain, know them well because it is a good place for an ambush.
By learning the Way of warfare, according to the rules of Yin and Yang, the general can secure victory. If he knows how to turn the terrain to his advantage, he can pass it effectively, but also trap the enemy in a disadvantageous position. If the general has no choice but to pass through difficult terrain, knowledge of their every nook and cranny is essential to avoid an ambush.
If an enemy is near but does not attack, he has strong ground. If he is far and baits you to attack, he has good ground and is ready to fight. If the trees move, he is advancing. If there are screens in the grass, he is trying to confuse you. Birds suddenly flying up are signs of an ambush, as are scared beasts. High clouds of dust suggest chariots are moving. Low dust suggests infantry are coming. Scattered dust indicates firewood is being collected. Pockets of dust suggest a camp.
If deception is key to war, the enemy is surely seeking to hoodwink the general. He must be able to see through these ruses. By seeing and understanding the clues that give away the enemy’s true position and situation, the general can avoid being duped. Sun gives specific examples of how to read the signs of an enemy’s true circumstances, and as ever, perceiving nature is key to this.
Words of humility but camp preparations suggest an attack will come soon. Aggression could herald a retreat. Chariots arriving first on the sides indicate a formation. Offers of peace but no terms indicates deception. A lot of activity indicates expectation. Some men advancing and others retreating indicate they are laying bait.
The general should not read the enemy’s situation by how it appears on the surface. He should know about every movement the enemy makes, so he can read between the lines of his approach to diplomacy. A show of weakness could actually indicate strength, and vice versa.
Soldiers bent over their spears are hungry. If the water bearers are drinking first, the army is thirsty. If the enemy does not take an opportunity, they are exhausted. The ground is empty if birds are gathering. Shouts in the night reveal fear in the enemy camp. If the men are confused, it suggests the enemy general is not respected. Banners and flags moving around indicate disorganization.
Natural signs give away the enemy’s circumstances. The general must have eyes and ears in place to see the realities of the enemy camp so he can assess their strength or weakness. Sun offers examples of behaviors signaling weakness, such as a lack of resources or respect.
If the officers are often angry, the men tire. If they are feeding meat to the men and grain to the horses, if they do not keep an orderly camp, they are at bay. Men whispering in groups is sign of dissatisfaction. Overly rewarding the men reveals desperation, and excessively punishing them indicates exhaustion.
Changes in behavior or routine belie the enemy’s weaknesses. If the men are eating the cart-pulling animals, or resorting to hunting, they are very hungry. If the cart animals are being fed the men’s bread grain, the enemy is encamped on disadvantageous terrain, with no vegetation. Such odd behavior can inform the general of an opportune time to strike.
If the general swings from being tyrannical to being in terror of his men, he is incompetent. Envoys with words of peace want to end hostilities. Ongoing, fierce warfare must be treated with vigilance. Numbers do not matter in war. It is all about concentrating your energy, knowing the enemy and earning the loyalty of the men. Underestimate the enemy and you will be captured.
Sun offers more analyses of specific situations and how to interpret them. An inconsistent general is incompetent. The general must be able to read into both diplomacy and fierce conflict. He must know the forms of war, the enemy’s position, and lead well—these three aspects determine his success rather than any physical aspects. Underestimating the enemy ensures failure.
If you discipline the men before they are loyal, they will be hard to manage, but if you don’t discipline loyal troops, they will be completely useless. Command with civility and manage with discipline, and you will earn their confidence. Sensible and consistent orders create loyalty and mutual trust, while the opposite breeds disloyalty.
The general is responsible for the ability and behavior of the men. It is almost like raising them as his own children—not spoiling them, but not disciplining them so harshly they resent him. Given how often Sun refers elsewhere to ensuring the men do not flee the battlefield, earning the men’s loyalty is a significant strength when taking on the enemy.