In the battle of World War IV, Cao Cao fought for many years at the same time, relying on the stable rear area. After Cao Cao collected nearly one million yellow turban insurrectionary troops and their families, he only transferred tens of thousands of elite soldiers from the three hundred thousand yellow turban insurrectionary troops to form Qingzhou soldiers, and the rest were placed by Cao Cao to farm and grow grain.
Food is the guarantee for Cao Cao to fight everywhere. The battle of Guandu was the biggest battle Cao Cao experienced in the first half of his life, with large scale, high intensity and long duration. This is a great test for Cao Cao. The reflection does record that Cao Cao's food is not much:
The History of the Three Kingdoms and Emperor Wudi: When there was not much public grain, Yu Xun and I wrote to discuss my wishes.
This time is already the most important moment in the battle of Guandu. The two sides camped in Guandu and confronted each other in strength. At that time, Yuan Shao was slightly stronger than Cao Cao, and it was very painful to confront Cao Cao. Once the war becomes a war of attrition, it will be won by strength. Cao Cao won the war in his early years basically by strategy, such as recovering millions of yellow towels and destroying Lu Bu. The war of attrition is not what Cao Cao wants.
So Cao Cao wanted to withdraw, so he wrote to Yu Xun for his advice. Yu Xun quickly wrote a reply to Cao Cao, which read as follows:
I thought Shao learned that there were many people gathered in Guandu and wanted to know whether the referendum would win or lose. The public is weak and strong. If it can't be controlled, it will be used. This is a great opportunity in the world. Besides, bugonger can gather people without having to. Husband in SHEN WOO wise SHEN WOO, supplemented by Dashun, what direction is not good! Follow it.
Yu Xun thought: Yuan Shao assembled all his troops in Guandu to fight with us. Now is the critical moment, we can't retreat. If we retreat, we will be defeated. Besides, Yuan Shao's talent is not enough, and we have the destiny of the son of heaven. How can we not win?
After that, Cao Cao listened to Yu Xun's advice and did not withdraw his troops. You should know that Cao Cao's commissary in the front line was raised by Yu Xun in the rear. If there is no food, will Yu Xun advise Cao Cao to stick to it? The history books only say that Cao Cao has little food and not enough food. Since Yu Xun can persuade Cao Cao to persist, of course he can get food, otherwise what's the point of persisting?
From this point of view, Cao Cao is not short of food, but lack of confidence. Perhaps this letter itself means that Cao Cao is testing Yu Xun. You know, during the battle of Guandu, many Cao Cao secretly wrote to Yuan Shao. Cao Cao can't be without ideas. His letter may just be sounding out Yu Xun, but it is not really short of food.
Besides, Cao Cao's troops in Guandu front are obviously not as much as Yuan Shao's. Yuan Shao has 1 10000 troops at Guandu front, while Cao Cao has only 30,000 to 40,000 troops at most. If the army consumes less food, there will be no more Yuan Shao. Besides, there are millions of yellow turban insurrectionary families growing grain behind Cao Cao, at least there is not enough food. In fact, after the Yanzhou War triggered by the Chen Gong Rebellion, Cao Cao almost never lacked food.