Master Sun says that war is a very serious business for a nation. It is a matter of life and death, survival and extinction, and is something to be carefully considered. There are five fundamental aspects to be considered when preparing for war: the Way, heaven, earth, command, and discipline. The Way leads to unity between the general and the men, heaven refers to Yin and Yang, earth means terrain and life or death, command is about the general’s temperament and ability, and discipline is the organization of the army. Every commander that can grasp these ideas can win, but he who fails to grasp them loses.
The author and narrator, Sun, does not revel in warfare. Instead, it is a solemn matter of deadly significance that not only involves people but also heaven itself. From the opening lines, Sun makes clear that bloodthirstiness or barbarity of any sort are not suitable approaches to conflict. War is about survival, and by extension, ultimately about protecting peace. He uses pairs of opposing concepts to outline the sometimes devastating consequences of the leaders’ decisions and actions, reflecting the binary nature of the forces at play in war, and indeed the whole world, as represented by Yin and Yang.
In preparing for war, the general must look at which ruler has the Way, which general is able, which army has heaven and earth, which has more discipline, which is stronger, and which is better trained and more organized. One can work out who will win and lose from these alone. The reader that learns the lessons that Master Sun has to offer will win, while those who do not take the lesson to heart will lose. Choose the best plan—prepare it and then execute it. Take advantage of opportunities.
To a certain extent, Sun argues, the side that will be victorious can be calculated in advance based on the state leaders’ integrity, ability, and wisdom. The most morally upstanding ruler will have heaven on his side. The general that best understands the art of war will lead his side to triumph, as he determines the entire army’s proficiency. Based on these aspects, it is more important to plan well than to charge into battle and hope for the best. Better to take stock of your position in advance, and avoid engaging the enemy if the most likely outcome is defeat. As an experienced general, Sun’s advice can lead the way to victory, but ignoring his lesson will allow folly to prevail. This characterizes him as a general for hire, as many battle-scarred warriors were in his day. However, the implication could simply be rhetorical—exhorting the reader to employ his advice.
War is all about deception, so an able person should seem incapable, a moving army should seem stationary and should appear to be far when it is near, and vice versa. Draw out the enemy with bait and hit him with chaos. If the enemy is full then be prepared, and if he is strong avoid him altogether. If he is furious then upset him, if he is weak then fan his pride. If he is at ease, then fluster him. If his men are united, divide them. Attack him where he doesn’t see it coming and show up when least expected.
Everything has an opposite—all emotions, actions, and abilities. The wisest generals perceive the subtle balance of Yin and Yang in the world around them, and use that knowledge to their advantage, while also deceiving the enemy general to obscure his perception. Appearing incapable will cause the enemy to underestimate the general, while the latter fully understands his enemy’s true weaknesses. This gives him the upper hand in the fray. By understanding the enemy’s weakness, the general can specifically target those points to win a quicker, smoother victory. For example, if the enemy general is prone to anger, find a way to insult him personally, and he will make a rash decision, to his peril. This could save many lives in the general’s army, rather than pitting them against well-prepared opponents.
Victory cannot be planned out in advance, but the side that prepares the most beforehand will win the day. The side with the least effective planning in the temple meetings will lose. Having more (generally) will lead to victory, having less makes for uncertainty, while having none will lead to defeat. This is Master Sun’s view, which shows him who will be the victor.
Preparation wins most of the battle for a general—the side that has considered and planned the matter more thoroughly will prevail. However, that does not mean one can plan for every detail. In the chaos of the real world, nothing stays exactly according to plan. But based on the leaders’ wisdom, insight, and contingency planning, the outcome can still be predicted in advance.