Master Sun says there are different forms of terrain: accessible, entangling, deadlock, enclosed, precipitous, and distant. Accessible is open to all—he who has the high ground and sure supplies has the advantage. Entangling means advancing is an option but retreating is hard. If the enemy is unprepared, attack, but it will be hard to retreat if necessary.
Returning to discussing the forms of terrain, Sun offers advice on the proper approach to warfare in each type of situation and landform. The general must learn the best strategies to employ in every circumstance, often in advance, because once he makes a decision, he might not be able to return.
On deadlock terrain there is no advantage for either side. Do not fall for the enemy’s bait or move, but retreat to draw him out. When half of his men are out, strike. Enclosed terrain calls for getting there first. Block it and wait for the enemy, but if he does so, do not follow him. But if he does not block it, follow.
Strategy is key on difficult terrain. The general must mislead the enemy to force him to make a mistake, which can then be turned to the general’s advantage. The general must watch his step closely, and not fall for any traps himself.
On precipitous terrain, if you arrive first, take the high ground. If the enemy gets the high ground, lure him out by retreating. If strengths are equal on distant terrain, it is hard to engage and there is no advantage. The general must study these terrains and their Ways.
High ground is a necessity in warfare, as Sun mentions this central strategy numerous times. Yet, even without the high ground the general has options available to him. He must know these well, so that he is never exposed and unsure of how to act.
The general, not nature, is at fault for the following calamities: flight, impotence, decay, collapse, chaos, rout. If the overall strengths of two armies are matched but one is much larger, the result is flight. When officers are weak although the men are strong, this leads to impotence. If officers are strong but the men weak, this is decay. If the officers are headstrong and charge into battle before the general orders it, the outcome is collapse.
Sun details the real-life consequences of character faults in the general. These examples emphasize Sun’s view that any failure in the army is ultimately the general’s fault. His men’s weaknesses stem only from the general’s inability to lead or strategize. As such, these examples are warnings.
If the general is weak and inconsistent, the result is chaos. If the general underestimates the enemy and pits a smaller force against a larger one, there will be rout. These are the six ways of defeat. The general must learn them well. Terrain can be an ally. The best generals assess the enemy, the terrain, and the difficulties involved. The one that understands and practices this will win. Those who do not know will lose.
In all, Sun outlines six main ways the general’s inability can lead to disaster. He details each so the general can avoid such catastrophe. Instead, the general should learn the proper approaches to each terrain to use the land to his advantage. This is the best way to secure victory—taking the path of least resistance through tough terrain and striking the enemy where he is weakest. This is only possible with understanding, insight, and wisdom.
Even if a ruler says not to fight, if victory is certain, then fight. The same is also true if the rule says to fight but defeat is certain. The general who makes decisions without seeking fame or fearing blame will protect the people, serve his lord, and be called the jewel of the realm. The good general sees his men as his children. They will go with him wherever and face death beside him. If he is generous and affectionate but cannot command or give orders, or if he is chaotic, then the men will be like spoiled children.
While the general serves the ruler, he can ignore orders from the court if he knows he can secure victory. Because he takes on this authority, he therefore takes all the responsibility too. It is his job to protect the ruler, the state, and its people, and so he cannot think of selfish ends, or seek glory in war. When the general sees his role in this way, his men will be loyal and follow him to any end. Again, Sun describes the relationship between the general and the men as a father/son relationship, similarly to how leading contemporary philosopher Confucius talked about all social roles as relating to this dynamic—leader/lead, husband/wife, parent/child, master/servant. This, Confucius argued, was the best way to maintain social harmony.
If the general knows his own men can advance but does not see that the enemy is not vulnerable, victory is uncertain. If the enemy is vulnerable but the general’s men are unprepared, victory is not assured. If he knows the enemy and his own troops but not the terrain, he cannot be sure of victory. The wise general is never confused when he moves. He always knows his plan. So, if you know the enemy and know yourself, you can have no doubt of victory in a hundred battles. Knowing heaven and earth leads to complete victory.
Success depends on knowing all aspects of the battle. The general cannot trust to his men’s strength alone. He must know the enemy’s plans and circumstances as well as he knows his own. Yet he must not assume he knows his own men well—he must also stay on top of his own circumstances. Victory is only assured when the general can perceive and control the whole battlefield. But when he does, he can be certain of victory in every battle he fights.