Master Sun says the ruler gives orders to the general, who assembles the men and an army. He makes camp opposite the enemy. The real work comes with the battle itself. The difficulty is in making the crooked straight, or making an advantage out of disadvantage. Take a winding route to bait the enemy and win. Leave after the enemy but arrive first. This is mastering the crooked and the straight.
The general serves the ruler’s interests—sharing the same enemy. When it comes to the actual fighting, it is all about strategy. The general must use every opportunity available and create an advantage. Sun refers to this as making the crooked straight, which is similar to making the best of a bad situation, but in a way that ensures victory.
The battle can bring success or peril. You might throw your entire force into the fray but lose. If you abandon the camp you might lose the equipment. Forced marches over 30 miles lead to losing the officers—this will separate the weak from the strong and only one in ten will arrive. Over 15 miles you’ll lose half the men. For ten miles, two in three will arrive.
There is everything to win or lose in battle. Sun seems to discuss morale in minute detail, but more likely the numbers could be considered symbolic. In essence, his point is that there is always a balance between pushing the men too hard and getting to the battle first.
Without equipment, provisions, and stores, the army is lost. Without knowing your enemy’s plans you cannot form alliances. If you don’t know the terrain you cannot march. Without local advice you cannot know the terrain and exploit it. War is about deception. Move when it is advantageous. Division and unity are the elements of change in war.
Sun impresses the fact that there are many aspects to consider in war, and oversight in any of these could make the army vulnerable. Instead, the general must be all-knowing, while keeping a veil over his enemy’s eyes. The general must confuse and deceive the enemy general to ensure he alone has the upper hand.
Be like a “rushing” wind, a “stately” forest, “ravaging” fire, a “still” mountain, the “impenetrable” night, and “swift” lightning or thunder. Take booty from the countryside and share what is found. Be sure before you move. He who can master the crooked and the straight will win. This is the art of doing battle.
Sun uses powerful natural imagery to emphasize the importance of understanding natural laws—by understanding what makes fire so destructive, the general can lead his army with the same devastating consequences, and so on. Sun also repeats the wisdom of plundering the enemy territory, for the sake of efficiency. The general that can understand how to make the most of all circumstances will win the battle.
When you cannot hear or see, use gongs, drums, flags and banners. They are the army’s eyes and ears. When the army is organized it moves together. This is how you manage many. When it is nighttime, use torches and drums. Banners and flags can be used in daytime.
The general must marshal his men effectively. There are tried and tested ways of doing this. By using such methods, the general can lead the men even if he cannot see them himself.
The whole army can be disheartened. The general can lose his cool. The men are sharpest in the morning, slower by noon, and miss home in the evening. The skillful general avoids the sharpest, and attacks the slow and homesick. This is mastering the spirit. Meeting chaos with discipline and calm is mastery of mind.
The psychological aspects of warfare are just as important as the physical. Men’s ability is dictated just as much by their thoughts as by their physical strength. The general must also consider these aspects when timing battle. He must also remain dignified no matter the circumstances, and keep his cool to lead the men.
Counter distance, exhaustion and hunger with closeness, ease and plenty. This is mastering strength. Do not engage an army with ordered banners or perfect formation. This is mastering change. The axioms of war are to not attack uphill nor an enemy with a hill to his back. Do not fall for a fake retreat. Do not attack sharp troops. Do not fall for bait, nor obstruct a retreating army. Leave a path for a besieged army. Do not harass an enemy that is at bay. This is the art of war.
The general must find ways to avoid these weaknesses, while enforcing them on the enemy, and seeking the opposing strengths. He should avoid a strong army, or one that is well-positioned. The general must watch out for the enemy’s tricks, and know the enemy’s true circumstances. He should not overextend his army to punish an already defeated enemy, which could endanger his men or waste his resources.