Xu You 許攸 was an advisor to Yuan Shao. During the Battle of Guandu he defected to Cao Cao and told him about Yuan Shao's poorly defended supply base in Wuchao, eventually leading to Yuan Shao's defeat.
Not much is known about Xu You before he joined Yuan Shao, but he was known to be greedy and a friend of both Yuan Shao and Cao Cao. He did not participate in the debate for the next heir of the Yuan family but he was hated by his fellow peers due to his greediness and thus, having his wife arrested as a warning. Shen Pei 審配 told Yuan Shao about his family that they were locked up for charges of corruption which made Yuan Shao more careful then dealing with him.
Xu You became an adviser at the Battle of Guandu and kept advising Yuan Shao to send troops to defend their lightly defended supply depot at Wuchao. Yuan Shao however did not heed his advise and told him, “You still have the cheek to present your strategies in front of me?” Xu You was furious at his response and quickly left Yuan Shao’s services and joined Cao Cao.
During Cao Cao’s services, he told Cao Cao about Yuan Shao’s granaries at Wuchao and advised him to attack there to completely drain the entire morale of the Yuan army. Cao Cao’s men were suspicious of him but Xun You and Jia Xu 賈詡 urged Cao Cao to take his plan into action. The plan worked and Wuchao was all burnt down by Cao Cao’s men as they disguised themselves as Yuan Shao’s men.
Later, however, Xu You addressed Cao Cao in public by his childhood name. Cao Cao smiled, but soon afterwards had him executed.
Fact vs. Fiction
- …Xu You Was not executed by Xu Chu, but by Cao Cao.