The twenty-fourth year of Jian'an (219) was destined to be an extraordinary year, first Liu Bei finally captured Hanzhong from Cao Cao after more than two years of bitter fighting, then took the eastern three counties and entered the throne of Hanzhong under the persuasion of the group of ministers, Guan Yu, who was far away in Jingzhou, took the opportunity to raise troops to the north to launch the Battle of Xiangfan, once besieged Cao Ren at Fancheng and flooded the Forbidden Seventh Army, and for a while, Cao Cao even wanted to move the capital to avoid Guan Yu's troops.
The capture of Hanzhong and the three eastern counties was the peak of Liu Bei's strength, but for Cao Cao 219 was the year he faced the most difficulties, and it was also the year he suffered the most losses: two military commanders of the two major theaters, one killed and the other surrendered. Let's take a look at them one by one.
Among the thirteen states in the late Han Dynasty, the nine prefectures of Sili, Ji, Qing, Xu, You, He, Liang, Yan, and Yu were all in Cao Cao's hands, and there were many places where the territory needed to be defended, and there were fierce enemies in the four directions of the southeast, southwest, and northwest, so during the Cao Cao period, there were four major defensive areas, namely the eastern line of Hefei, the southern line of Jingxiang, the western line of Yongliang, and the northern line of guarding against the nomadic peoples of northern Xinjiang and the first line of Youyi, and the corresponding supreme military commanders were General Zhengdong. The generals of Zhengnan and Zhengxi (the relative importance of the northern front was relatively low, so there was no general of Zhengbei, and the generals in charge of the northern frontier at that time were Cao Cao's son Beizhonglang and Cao Zhang).
In 216, Cao Cao was made the King of Wei, and his authority was further expanded, with the authority to appoint sifang generals, and the four generals before Cao Cao's death were the former general Xiahou Huan, the left general Yu Ban, the right general Le Jin, and the rear general Zhu Ling.
The Battle of Hanzhong, which began in 217, lasted more than two years, Liu Bei was bound to win the main force in Hanzhong, Cao Cao did not pay attention to it at first, and the person responsible for fighting Liu Bei was the highest military commander of the Western Front, Xiahou Yuan, and at the beginning of the battle of the lower defense, Cao Jun had the upper hand, Cao Xiu and Cao Hong killed Lei Tong, Wu Lan and repelled Zhang Fei and Ma Chao, and then Xu Huang defeated Chen Shi at Mamingge Road.
The Battle of Dingjunshan became the key to turning the tide of the war between the two sides, Fa Zheng set up a plan step by step, Huang Zhong killed Xiahou Yuan in one battle, xiahou Yuan also became the highest rank person in Cao Wei's battle, although Cao Cao personally led a large army to come, but the demoralized Cao army finally defeated hanzhong in May 219, and Cao Cao not only lost Xiahou Yuan, but also lost Hanzhong.
Cao Cao's blows were far more than that, in July 219 Guan Yu launched the Battle of Xiangfan, because Cao Cao's main force was stationed in Chang'an for several months after the defeat of Hanzhong, and it was not until October that he returned to Luoyang, so the southern front was empty, and the general Cao Ren was besieged by Guan Yu in Fancheng, unable to move, and Cao Cao sent the left general Yu Ban to lead the Seven Armies of 30,000 soldiers and horses to aid Cao Ren.
Although Cao Ren was a general of Zhengnan, Yu Ban not only had the status of a general on the left above that of General Zheng Nan, but also had a false festival in Yu Ban, which had great power, and nominally had the right to kill and seize in wartime, and even Cao Ren, who had the right to have the right to fake festivals, was also under his jurisdiction, so at this time Yu Ban was at least ostensibly the supreme military commander of the Jingxiang Theater.
It is precisely because of this that Guan Yu's flooded Seventh Army Pound Was killed and Yu Ban surrendered would bring such a great shock to Cao Cao, Yu Ban was the highest rank person under Cao Cao at this time, and even Xiahou Huan was not as good as him (Xiahou Huan's former general was only after the surrender was forbidden), and Yu Ban was also the only person in Cao Cao's army who had a false festival, a high-ranking military commander on the front line who surrendered to his opponent in battle, and Cao Cao could imagine how big the blow to him while losing huge losses!
If it were not for Sun Quan's secret peace with Cao Cao, Xu Huang would have properly commanded and repelled Guan Yu, and Cao Cao, who had lost several generals Xiahou Yuan, Yu Ban and Pang De, as well as tens of thousands of soldiers and horses, might have finally moved the capital.