Subjugating the enemy's army without fighting is the true pinnacle of excellence.
Thus the highest realisation of warfare is to attack the enemy's plans; next is to attack their alliances; next to attack their army; and the lowest is to attack their fortified cities. This tactic of attacking fortified cities is adopted only when unavoidable.
Thus one who excels at employing the military subjugates other people's armies without engaging in battle, captures other people's fortified cities without attacking them, and destroys other people's states without prolonged fighting. He must fight under Heaven with the paramount aim of preservation. Thus his weapons will not become dull and the gains can be preserved. This is the strategy for planning offensives.
In general, the strategy for employing the military is this: If your strength is ten times theirs, surround them; if five, then attack them; if double, then divide your forces. If you are equal in strength to the enemy, you can engage him. If fewer, you can circumvent him. If outmatched, you can avoid him. Thus a small enemy that acts inflexibly will become the captives of a large enemy.
The general is the supporting pillar of state. If his talents are all-encompassing, the state will invariably be strong. If the supporting pillar is marked by fissures, the state will invariably grow weak.
There are three ways by which an army is put into difficulty by a ruler:
He does not know that the Three Armies should not advance but instructs them to advance, or does not know that the Three Armies should not withdraw and orders a retreat. This is termed entangling the army.
He does not understand the Three Armies' military affairs but directs them in the same way as his civil administration. Then the officers will become confused.
He does not understand the Three Armies' tactical balance of power but undertakes responsibility for command. Then the officers will be doubtful.
When the Three Armies are already confused and doubtful, the danger of the feudal lords taking advantage of the situation arises. This is referred to as a disordered army drawing another on to victory.
There are five factors from which victory can be known:
One who knows when he can fight and when he cannot fight will be victorious.
One who recognises how to employ large and small numbers will be victorious.
One whose upper and lower ranks have the same desires will be victorious.
One who, fully prepared, awaits the unprepared will be victorious.
One whose general is capable and not interfered with by the ruler will be victorious.
These five are the Tao to know victory.
Thus it is said that one who knows the enemy and knows himself will not be endangered in a hundred engagements. One who does not know the enemy but knows himself will sometimes be victorious, sometimes meet with defeat. One who knows neither the enemy nor himself will invariably be defeated in every engagement.