The Battle of Hanshui (汉水之战) was fought in 219 during Liu Bei’s Hanzhong campaign. Cao Cao sent a force to attack Zhao Yun’s camp on the Han River. Zhao Yun, outnumbered, left the gates open and withdrew his troops from view. The Wei vanguard feared an ambush and retreated. Zhao Yun then had the drums beaten and archers fire; his troops pursued and defeated the enemy. Liu Bei later inspected the camp and called the battle “Zilong’s full of courage” (子龍一身都是膽). The engagement is often cited as an example of the “empty fort” stratagem and of Zhao Yun’s calm under pressure.
Battle of Hanshui 汉水之战
In 219, during the struggle for Hanzhong, Cao Cao sent troops to oppose Liu Bei. At Hanshui (Han River) the two sides clashed; Zhao Yun's empty-fort ploy and counter-attack secured a Shu victory.