Cao Cao 's army disguised itself as a reinforcement unit from Yuan Shao and attacked Wuchao .
Thus at night , Cao Cao led 5,000 infantry and cavalry to attack Wuchao after leaving Cao Hong and Xun You in charge of his main camp at Guandu .
Cao Cao 's army disguised itself as a reinforcement unit from Yuan Shao and attacked Wuchao .
Thus at night , Cao Cao led 5,000 infantry and cavalry to attack Wuchao after leaving Cao Hong and Xun You in charge of his main camp at Guandu .