Be extremely subtle, even to the point of formlessness. Be extremely mysterious, even to the point of soundlessness. Thereby you can be the director of the opponent's fate.
Generally, management of many is the same as management of few. It is a matter of organization. And to control many is the same as to control few. This is a matter of formations and signals.
Of all those in the army close to the commander none is more intimate than the secret agent; of all rewards none more liberal than those given to secret agents; of all matters none is more confidential than those relating to secret operations.
On dispersive ground, therefore, fight not. On facile ground, halt not. On contentious ground, attack not. On open ground, do not try to block the enemy's way. On the ground of intersecting highways, join hands with your allies. On serious ground, gather in plunder. In difficult ground, keep steadily on the march. On hemmed-in ground, resort to stratagem. On desperate ground, fight.