Huarong Dao Guan Yu yi is Cao Cao, is a wonderful story in the "Romance of the Three Kingdoms", and in the description of the "Romance of the Three Kingdoms", Zhuge Liang sent Guan Yu to guard Hua Rong Dao's purpose, in order to release Cao Cao, it can be said that letting go of Cao Cao is Zhuge Liang's intention, so why did Zhuge Liang do this, assuming that Guan Yu killed Cao Cao, then what will be the consequences?
If Guan Yu killed Cao Cao, it would be detrimental to Liu Bei's clique as a whole, and this was the fundamental reason why Zhuge Liang let Cao Cao go through Guan Yu's hand. Guan Yu's release of Cao Cao occurred in the course of Cao Cao's defeat at the Battle of Chibi and his escape to the north. Before the Battle of Chibi, Cao Cao barely unified the north and swept away Yuan Shao, Lü Bu and others, so he gathered heavy troops to the south, intending to pacify the south in one fell swoop, thus completing the unification of the whole world. As Cao Cao's army moved south and Liu Chun of Jingzhou surrendered, Sun liu and Liu's families were under pressure to form an alliance and launch the Battle of Chibi.
In the Battle of Chibi, Cao Cao was defeated, but Cao Cao could not die, at least for Liu Bei's clique. First of all, Cao Cao belongs to the actual controller of the Central Plains, once Cao Cao dies, whether it is within the Cao clique or other forces in the north, I am afraid that they will be ready to move, and at this time, Cao Cao in the north is only reluctantly unified, in fact, there are forces such as Ma Teng. Once the Cao clan was unstable internally, it was likely that the north would once again form a situation in which the princes would rise together.
At this time, Liu Bei's group was in the Yangtze River Basin in the south, and its foundation was still shallow, and its strength was insufficient, so it was impossible to participate in the northern hegemony. Moreover, sun liu's alliance itself originated from the strong pressure of Cao Cao in the north, and once Cao Cao died, chaos arose in the north. Then it is conceivable that the Eastern Wu side, which has just won a great victory in the Chibi War, will inevitably take this opportunity to sweep through all parts of the south, strive to unify the south, and then swing its division north, trying to retake Cao Cao's route in the opposite direction and unify the world. At this time, Liu Bei was no longer an ally of Sun Quan, but an obstacle to his unification of the south. At this time, Liu Bei's strength was not enough to turn his face with Eastern Wu, which had been rooted in Jiangnan for a long time, so Cao Cao could not die at this time, and Liu Bei's clique needed the existence of Cao Cao, an enemy, to suppress Eastern Wu, so as to ensure the existence of Sun Liu's alliance in the short term, so as to give himself time to develop.
There was another reason why Cao Cao could not die, that is, a figure who was ignored by many people in the Three Kingdoms, Emperor Xian of Han. Cao Cao was holding the Son of Heaven hostage to order the princes, and Emperor Xiandi of Han was just Cao Cao's puppet. But that was when Cao Cao was there, if Cao Cao died, the north fell into chaos, and once again the princes rose up, Cao Cao's forces partially surrendered to Sun Liu, and the north had to face other challenges such as Ma Teng, then the remaining Cao forces would not defect to Emperor Xian of Han. It should be known that Cao Cao's daughter was also married to Emperor Xian of Han, and the Cao family was a foreign relative, and Emperor Xian of Han also needed a force that could be controlled if he wanted to take power. Whether it was such a development or not, after Cao Cao's death, Emperor Xiandi of Han always had a chance to get out of trouble. And once The Emperor Xiandi of Han, the righteous emperor, was able to get out of trouble and control some of the power, it was not a good thing for the ambitious people who aspired to the world. Therefore, Cao Cao could not die.
It was precisely for the above two reasons that Zhuge Liang deliberately let Guan Yu let Cao Cao go.