In any battle the element of surprise can provide an overwhelming advantage. Even when face to face with an enemy.

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Surprise can still be employed by attacking where he least expects it. To do this you must create an expectation in the enemy's mind through the use of a feint.

In AD 200, Yuan Shao and Cao Cao fought a decisive battle. Yuan Shao, with the advantage of terrain and troop strength, wanted to block the enemy's route of retreat (Battle of Guandu).

Yuan Shao ordered general Yan Liang to lead 10,000 soldiers to occupy the enemy's strategic Baima city.

Cao Cao was told of the enemy's plan. He summoned his aides to help think of a solution. One of his aides, Xun You said, "Let's show as if we're crossing the river to attack Ye city. Yuan Shao will send some troops westwards. In the meantime, we can surround Baima and attack the remaining Yuan Shao troops."

Falling for the ruse, Yuan Shao led some troops to reinforce Ye city. Yan Liang surrounded Baima and believing that Cao Cao's army was attacking Yanjin and Ye, thought that Cao Cao will surrender in a few days time. Meanwhile, Cao Cao made his troops travel day and night to Baima.

Yuan Shao reached Yanjin and found nobody there. Cao Cao managed to kill Yan Liang and thus the siege was lifted.