SUN ZI said:  Generally in wax the best thing of all is to take the enemy's state whole and intact, to ruin it is inferior to this. To cap ture the enemy's  army entire is better than to destroy it; to take intact a battalion, a company or a five-man squad is better than to destroy them2  Hence to win one hundred victories in one hundred battles is not the acme of skill.  To subdue the enemy without figh ting is the supreme excellence.

  　Thus, the best policy in war is to attack the enemy's strategy. The second best way is to disrupt Ms alliances through diplomatic means.  The next best method is to attack his army in the field. The worst policy is to attack walled cities.  Attacking cities is the last resort when there is no alternative.  It takesat least three months to make mantlets and shielded vehicles ready and prepare necessary arms and equipments.  It takes at least another three  months to pile up earthen mounds over against the walls.  The general unable to control his impatience will order his troops to swarm up the wall like ants with the result that one third of them are slain, while the cities remain untaken.  Such is the calamity of attacking walled cities.  Therefore,  those skilled in war subdue the enemy's army without fighting.  They capture the enemy's cities without assaulting them and overthrow his state without protracted operations. Their aim must be to take all under laeaven intact through strategic superiority.  Thus, their troops are not worn out and their triumph will be complete.  This is the art of attacking by stratagem.

    Consequently, the art of using troops is this: When ten to the enemy's one, surround him.  When five times his strength, attack him. ff double his strength, engage him.  If equally matched, be capable of dividing him. If less in number, be capable of defending yourself. And if in all respects unfavourable, be capable of eluding him.  Hence, a weak force will eventually fall captive to a strong one if it simply holds ground and conducts a desperate defence.

    Now, the general is the bulwark of the state: If the bulwark is complete at all points, the state will surely be strong; if the bulwark is defective, the state will certainly be weak.

    Now, there are three ways in which a sovereign can bring misfortune upon his army:

    1. By ordering an advance while ignorant of the fact that the army cannot go forward, or by ordering a retreat while ignorant of the fact that the army can not fall back.  This is described as 'hobbling the army'.

    2. By interfering with the army's administration without knowledge of the internal affairs of the army.  This causes officers and soldiers to be perplexed.

    3. By interfering with direction of fighting, while ignorant of the military principle of adaptation to circumstances.  This sows doubts and misgivings in the minds of his officers and soldiers.

    If the army is confused and suspicious, neighbouring rulers will take advantage of this and cause trouble.  This is simply bringing anarchy into the army and flinging victory away.

    Thus, there are five points in which victory may be predicted:

    1. He who knows when to fight and when not to fight will win.

    2. Itc who understands how to handle both superior and inferior forces will win.

    3. He whose ranks are united in purpose will win.

    4. He who is well prepared and lies in wait for an enemy who is not well prepared will win.

    5. He whose generals are able and  not interfered with by the sovereign will win.

    It is in these five points that the way to victory is known.

    Therefore, I say:  Know the enemy and know yourself, and you can fight a hundred battles with no danger of defeat.  When you are ignorant of the enemy but know yourself, your chances of winning and losing are equal.  If ignorant both of your enemy and of yourself, you are sure to be defeated in every battle.