War is an equation with many unknowns; and this already refutes the thesis of invincibility. History does not know invincible armies. The wars of the past show us that even armies that had won brilliant victories for decades, in some cases were not only defeated but even disintegrated and ceased to exist. Such a fate, for example, befell the army of Napoleon, who for almost two decades kept the whole Europe under its boots. The army needs to instill a spirit of confidence in its power, but not in terms of boasting. Bragging about invincibility brings harm to the army.

It is the rule in war, if ten times the enemy's strength, surround them; if five times, attack them; if double, be able to divide them; if equal, engage them; if fewer, defend against them; if weaker, be able to avoid them.

As any military strategist knows, it's impossible to win a defensive warfare. Defensive war is doomed to defeat. To win a war, you have to launch an attack. You have to go on the offensive. You have to attack the enemy. You have to set him back on his heels. You have to take the initiative. You have to be positive. You have to attack and invade and overpower. You can't just sit there and try to ward him off while he attacks and invades, or he'll finally overpower you.

It is much better to overcome the enemy by famine, surprise or terror than by general actions, for in the latter instance fortune has often a greater share than valour. Those designs are best which the enemy are entirely ignorant of till the moment of execution. Opportunity in war is often more to be depended on than courage. (General Maxims)

It is the rule in war, if our forces are ten to the enemy's one, to surround him; if five to one, to attack him; if twice as numerous, to divide our army into two.

first lay plans which will ensure victory, and then lead your army to battle; if you will not begin with stratagem but rely on brute strength alone, victory will no longer be assured

It is the rule in war, if our forces are ten to the enemy's one,
to surround him; if five to one, to attack him; if twice as numerous,
to divide our army into two.

Move not unless you see an advantage; use not your troops unless there is something to be gained; fight not unless the position is critical. No ruler should put troops into the field merely to gratify his own spleen; no general should fight a battle simply out of pique. If it is to your advantage, make a forward move; if not, stay where you are. Anger may in time change to gladness; vexation may be succeeded by content. But a kingdom that has once been destroyed can never come again into being; nor can the dead ever be brought back to life. Hence the enlightened ruler is heedful, and the good general full of caution. This is the way to keep a country at peace and an army intact.

"17. Thus we may know that there are five essentials for victory: (1) He will win who knows when to fight and when not to fight. [Chang Yu says: If he can fight, he advances and takes the offensive; if he cannot fight, he retreats and remains on the defensive. He will invariably conquer who knows whether it is right to take the offensive or the defensive.] (2) He will win who knows how to handle both superior and inferior forces. [This is not merely the general’s ability to estimate numbers correctly, as Li Ch’uan and others make out. Chang Yu expounds the saying more satisfactorily: “By applying the art of war, it is possible with a lesser force to defeat a greater, and vice versa. The secret lies in an eye for locality, and in not letting the right moment slip. Thus Wu Tzu says: ‘With a superior force, make for easy ground; with an inferior one, make for difficult ground.’"] (3) He will win whose army is animated by the same spirit throughout all its ranks. (4) He will win who, prepared himself, waits to take the enemy unprepared. (5) He will win who has military capacity and is not interfered with by the sovereign. [Tu Yu quotes Wang Tzu as saying: “It is the sovereign’s function to give broad instructions, but to decide on battle it is the function of the general.” It is needless to dilate on the military disasters which have been caused by undue interference with operations in the field on the part of the home government. Napoleon undoubtedly owed much of his extraordinary success to the fact that he was not hampered by central authority.] 18. Hence the saying: If you know the enemy and know yourself, you need not fear the result of a hundred battles. If you know yourself but not the enemy, for every victory gained you will also suffer a defeat.

(1) He will win who knows when to fight and when not to fight. (2) He will win who knows how to handle both superior and inferior forces. (3) He will win whose army is animated by the same spirit throughout all its ranks. (4) He will win who, prepared himself, waits to take the enemy unprepared. (5) He will win who has military capacity and is not interfered with by the sovereign. 18. Hence the saying: If you know the enemy and know yourself, you need not fear the result of a hundred battles. If you know yourself but not the enemy, for every victory gained you will also suffer a defeat. If you know neither the enemy nor yourself, you will succumb in every battle.

In battles, when the armies are in confrontation, attack the enemy's strong points and, when you see that they are beaten back, quickly separate and attack yet another strong point on the periphery of his force. The spirit of this is like a winding mountain path. This is an important fighting method for one man against many. Strike down the enemies in one quarter, or drive them back, then grasp the timing and attack further strong points to right and left, as if on a winding mountain path, weighing up the enemies' disposition. When you know the enemies' level, attack strongly with no trace of retreating spirit.

Over a long period we have developed this concept for the struggle against the enemy: strategically we should despise all our enemies, but tactically we should take them all seriously. This also means that we must despise the enemy with respect to the whole, but that we must take him seriously with respect to each and every concrete question. If we do not despise the enemy with respect to the whole, we shall be committing the error of opportunism. Marx and Engels were only two individuals, and yet in those early days they already declared that capitalism would be overthrown throughout the world. But in dealing with concrete problems and particular enemies we shall be committing the error of adventurism unless we take them seriously. In war, battles can only be fought one by one and the enemy forces can only be destroyed one by one. Factories can only be built one by one. The peasants can only plow the land plot by plot. The same is even true of eating a meal. Strategically, we take the eating of a meal lightly—we know we can finish it. But actually we eat it mouthful by mouthful. It is impossible to swallow an entire banquet in one gulp. This is known as a piecemeal solution. In military parlance, it is called wiping out the enemy forces one by one.

To defeat your enemy you absolutely must stoop to its tactics. The whole idea that you shouldn't is something your enemy came up with.

To surprise the enemy is to defeat him.