声东击西　(shēng dōng jī xī)

Distracting Your Enemy with a Feint

This scheme is still widely applied, even in a common prank. Stand behind a person close to his or her right shoulder without the person knowing it, and then pat the person on his or her left shoulder. Ninety-nine out of 100 times, the person will turn left to find out who’s behind. A wrong move.

Such a wrong judgment could put you into a disadvantageous position in some cases and may prove fatal in a fight or war.

During the Eastern Han Dynasty (25-220 AD), the emperor sent Ban Chao, a famous military commander and diplomat, to the remote, western region to fight the Huns.

With only 25,000 soldiers at his command, Ban decided to first attack a small kingdom called Suoche because it had formed an alliance with the Huns. The king of Suoche sent for help from Qiuci, a kingdom to the north. The king of Qiuci immediately led a troop of 50,000 men to fight the Ban army.

Ban realized he could not win a battle with the joined forces of the two kingdoms if he fought them head-on. So, he sent out people to spread rumors that his army had decided to retreat. He ordered part of the army to run away to the east and he himself led the remaining troops to retreat pell-mell to the west.(https://www.daowen.com)

The Qiuci king was overjoyed when he heard the news and led his troops to chase Ban overnight.

Ban and his troops didn’t go far. When the night fell, they left the main road and hid themselves in nearby woods. After the Qiuci king and his men rushed past them to the west, Ban immediately ordered his troops to march back to the Kingdom of Suoche. Meanwhile, his troops who had earlier left for the east also came back and they launched a surprise attack against Suoche. Before dawn, the small kingdom’s defenses collapsed and the king surrendered.

After a whole night’s ghost chase, the Qiuci king failed to find a single soul of Ban’s troops. When he and his army were in a quandary, a messenger brought him the news that the Kingdom of Suoche was taken by Ban.

The Qiuci king then decided that there was nothing he could do to rescue his neighbor any more, and he withdrew his troops to his own kingdom.

So, in order to win a battle, always try to create an expectation in your enemy’s mind in the wrong direction and then attack him where he least expects it.