Lombardi's consultants are numerous and incompatible with each other. When the first battle was unfavorable and deadlocked, Xu You's nephew broke the law, and some people suggested that Xu You would participate in corruption, which made Yuan Shao very distrustful of Xu You. At that time, Cao Cao's food and grass could only last for three days, so he sent a letter back to Xu Du for begging, and was intercepted by Xu You, who came to report to Yuan Shao. But Yuan Shao no longer trusted Xu You, saying that he was a classmate of Cao Cao when he was young, and he was malicious, deceiving him with false letters and hitting him with sticks.

Xu You took refuge in Cao Cao with resentment, designed and burned Yuan Shao's grain depot camp nest, cut off Yuan Shao's food and grass, and caused Yuan Shao's army to be in chaos. After that, Cao Cao returned to Li's side and surrounded Gao Lan, the general of Yuan Shao, for his own use. Directly led to Yuan Shao's final failure.

Xu You (? -204) Ziyuan was born in Nanyang (now Nanyang, Henan). Originally a counselor under Yuan Shao's account, his family was arrested for breaking the law during the battle of Guandu. Therefore, he cast a treacherous vote for Cao Cao and set a plan for Cao Cao to sneak into the lair of Yuan Shao's army grain depot. Yuan Shao was defeated by Guandu. ?

Xu You is not a stupid person. From the place where he abandoned Yuan Shao and went to Cao Cao, we can see that he is not pedantic. For a consultant, he won't get great honor for providing a plan. He is treacherous and greedy, but he is by no means an arrogant man. According to historical records, his family was imprisoned when Yuan Shao defected to Cao Cao. When Cao Cao arrived in Yizhou, it was probably because Xu You learned that his family had been killed and had suicidal thoughts.

At that time, Liu Bei defected to Yuan Shao, and Xu You was a subordinate of Yuan Shao. Xu You befriended Cao Cao when he was young, so he remembered his old love and turned to Cao Cao. At the stalemate stage of the battle of Guandu, Cao Cao kept Guandu City for a long time, and his military strength was gradually lacking and his rations were exhausted. He sent an urgent messenger to Xudu to ask for help in arranging food and grass.

The messenger was stopped by Xu You, and the letter of urging food was exposed. So he provided Yuan Shao with an analysis of Cao Cao's troops stationed in Guandu. For a long time, many people will be empty. If there is an army attack on the starry night, Xu Du can win it at one fell swoop and Cao Cao can capture it. If Yuan Shao uses Xu You's plan to attack Xudu and Guandu, Cao Cao will be wiped out. ?

Unfortunately, the most needed advice is the least taken seriously. Yuan Shao is suspicious and willful, and thinks that Cao Cao is scheming. This grain reminder letter is a trick to lure the enemy. Because Xu You and Cao Cao were friends when they were young, Yuan Shao even suspected that Xu You had secretly contacted Cao Cao and acted as a spy for Cao Cao. Angry to kill it. So Xu Youcai defected to Cao Cao. At that time, Liu Bei contacted Liu Biao against Cao Cao for Yuan Shao's sake, so Xu Youcai could not vote for Liu Bei at that time.