According to Master Sun, there are five fundamentals the wartime general must assess: the Way, heaven, earth, command, and discipline. Only by perceiving and understanding the lessons and forms of each, Sun says, can the general emerge victorious in battle. Winning is about taking advantage of opportunity as well as confusing and outwitting the enemy. Though victory depends greatly on preparation, it also comes down to a general’s ability to respond to ever-changing circumstances and make decisions on the spot.
Sun further notes that, because war is a costly and complicated affair that drains the nation’s finances and morale, conflicts should be resolved as soon as possible. To that end, war should be fought only for victory, not out of bloodthirstiness. The general should act proportionately and compassionately, without overreaching or pushing his men too far; there is no sense in pointless killing when an enemy city can be taken whole. In fact, winning without fighting at all is the most desirable outcome.
The general is responsible not only for the army but also the nation’s strength as a whole. The general must know how to lead his troops and make his own decisions. He must know the enemy as well as his own forces. Most of all, a general must strategize well. Just as water crashes down a gorge, so too can the army overwhelm its enemy with a well-considered strategy. And though sheer numbers must be considered when strategizing, proper organization means that having fewer troops is not a problem.
All war, Sun says, is essentially about direct and indirect action—about understanding and working with, rather than against, the flow of the situation and the opportunities arising as the conflict unfolds. Regardless of the men’s ability, if the general reacts appropriately to changing situational dynamics, his men will crush the enemy, like logs rolling down a hill.
Sun further emphasizes the importance of confusing and weakening the enemy. By keeping his own plans a mystery, the general forces the enemy to split his troops to defend many points, as the opposing general does not know where the attack will come from. With enemy troops now thinned out, the general can better concentrate his attack. Forcing the enemy to prepare against an unknown attack thus weakens him. Of course, the general must not allow himself to be cornered in this same way; if the general does not know where the strike will come, his own troops will be thinned out and divided. Therefore, the general must know the enemy’s plan, his motivations, his weaknesses, while still disguising his own.
To be sure, each victory is individual; there is no go-to formula. Victories are won by responding to myriad potential situations, as the world is constantly changing. Thus, just as water flows downhill, an army must always seek the easiest path to victory and attack the enemy’s weakest point.
The fray, Sun continues, isn’t to be entered into lightly. Throwing the army into battle could mean losing both men and equipment, and as such the general must first be sure of the lay of the land. Different terrains determine the method of attack, while mountains, rivers, salt marshes, and level ground all require different strategies to cross. There are roads and armies to avoid altogether, Sun notes. Meanwhile, gongs, drums, banners, flags and torches keep the army orderly and of one mind. The wise general gauges his men’s morale as well as the enemy’s, and only attacks at the opportune time. He remains prudent despite temptations, and doesn’t fall into traps. Recklessness, cowardice, anger, arrogance, and misplaced compassion are all faults in a general, and if an army fails, it is likely the general was guilty of one of these five vices.
Beyond knowing the lay of the land, the general must read the land for signs of the enemy’s movements: if the enemy is not moving, it means he has found advantageous terrain. If, on the other hand, the enemy is baiting the general, then the enemy is leading him into disadvantageous terrain. The general also must watch the enemy’s men to see the true state of his army: are they tired, thirsty, hungry, despondent, disorderly? Is the enemy general changeable, tyrannical, incompetent? Numbers alone do not win a battle—wisdom, understanding, and loyalty do, and the men’s state and ability is the general’s responsibility.
Even so, the general should keep his strategies even from his men, who must trust him implicitly. The general alone is the commander, and so great is his responsibility that he can even ignore the ruler’s orders when the general—who is closer to the battle arena—knows better.
Turning to more practicalities, Sun notes that seizing something the enemy holds dear will bend him to the general’s will. Speed is also essential in war once decisions have been made, and plunder from the enemy is an efficient means to resupply the troops. Additionally, there are five things to target in a fire attack: men, supplies, equipment, warehouses, and lines of communication. The general must have the materials ready and know the best conditions to use these methods of attack, such as the right season. He must not be hasty but instead remain wise, as calamity cannot be undone. Being cautious can maintain peace.
Wars are expensive and hurt the whole nation, especially common people, so investing in a solid spy network is good financial planning. Spies should also be well-paid to ensure their loyalty. Double agents are a way to finding more spies, and so should be treated especially well. No one is closer to the general than his spies; with their information, he can know his enemy and attack his weakest points. Only the wisest general knows how to use them best.