In the twenty-fourth year of Jian'an (219 AD), Guan Yu set out from Nan Commandery to attack Xiangfan in the north, first defeating the Zhennan general Cao Ren who was guarding Jingzhou. Cao Cao ordered the Commander of the Seventh Army to come to the rescue, but Guan Yu took advantage of the surge in the Han River to flood the Seventh Army, killing a whole army and destroying it, and Yu Ban and the thirty thousand Cao army were captured. Cao Ren could only take thousands of remnants of his army and besiege Fancheng, and Lü Chang was also trapped in Xiangyang City.
At this time, most of fancheng was also flooded, and the generals of the Cao army and the residents of the city could only live temporarily on the highlands and rooftops, and the city walls collapsed in many places due to flooding. In addition, Guan Yu commanded the Jingzhou water army to besiege Fancheng, and there was no communication inside and outside, the grain and grass in the city would be exhausted, and the reinforcements would not arrive, and the people were panicked for a while.
Some people advised Cao Ren to abandon Fancheng as soon as possible and withdraw as soon as possible while the siege was not yet tight. However, Man Yu believed that at this time, Guan Yu's voice was greatly shaken, and the people's hearts south of Xuchang were floating. It was only before Fan Cheng fell that Guan Yu did not dare to go north. If Fancheng was abandoned and Guan Yu led his army north, then the south of Xuchang would be dangerous.
Cao Ren then made up his mind to hold the city and encourage his soldiers to coexist and die with the city, and finally insisted until Xu Huang led his troops to defeat Guan Yu and relieve the siege of Fancheng. Guan Yu also quickly had to withdraw his army because Sun Quan attacked Jingzhou, and was defeated and captured by the Wu army halfway because of the dispersion of the army.
Of course, there is a certain truth in the words of full favor, but judging from the situation of the two armies at that time, even if Cao Ren abandoned Fancheng and took the initiative to retreat, it would be difficult to change the historical results after Guan Yu captured Xiangfan.
Many people know that after Cao Ren was defeated by Guan Yu, Cao Cao ordered the forbidden soldiers to come to the rescue. But in fact, in addition to Yu Ban, Cao Cao also ordered Xu Huang to go with him. It was just that Xu Huang's troops suffered a lot of losses in the Battle of Hanzhong, and many new soldiers were replenished, and they did not recover their combat effectiveness for a while. Therefore, he did not go to Fancheng with Yu Ban, but stayed in Wancheng with his own men and horses.
The number of people under Xu Huang at this time is not recorded in the history books. However, he was one of the foreign generals that Cao Cao relied heavily on, and the commander's soldiers and horses should have at least a few thousand, plus there were originally thousands of soldiers from the prefecture and county and Cao Ren in the Wancheng area, and the total strength of Cao's army was at least more than 10,000.
During Guan Yu's Northern Expedition to Xiangfan, the jingzhou part actually controlled by Liu Bei's group was only three counties: Nan County, Wuling, and Lingling, and only about one-third of the entire territory of Jingzhou. The number of troops he could mobilize in the Northern Expedition was no more than 20,000 or 30,000 people. After the start of the Northern Expedition and the battle with the Cao army, it was inevitable that there would be damage, and after capturing Xiangfan, a certain number of soldiers and horses would have to be left behind, and after deducting the water division, Guan Yu could use to attack Wancheng's troops, which was about 10,000 or 20,000 people.
During the Three Kingdoms period, due to the limitation of technical conditions and limited means of siege, the defenders had great advantages. Famous generals such as Cao Cao, Sun Ce, Zhou Yu, Liu Bei, Zhuge Liang, Lu Kang, and Yang Hu all suffered a lot in siege battles, either ending in failure or taking a long time to succeed.
Wancheng is an important town in the north of Jingzhou, with thick walls. Cao Ren, Xu Huang, and Man Yu were all among the more outstanding generals under Cao Cao. Guan Yu was obviously difficult to conquer Wancheng in a short period of time when his troops were comparable to those of the other side, and the most optimistic estimate was that it would take three or five months to fight.
And such a long time was enough for Cao Cao to dispatch troops to rescue Wancheng in the future. Historically, Guan Yu flooded the Seventh Army in August, and by October at the latest, Cao Cao had successively sent Xu Shang, Lü Jian, and others to lead an army to reinforce Xu Huang, with at least 20,000 men before and after, and Xu Huang's strength had surpassed Guan Yu.5 Cao Cao also personally led an army to follow, preparing to personally face Guan Yu, and the advantages of Cao's army would be further expanded.
Therefore, even if Cao Ren abandoned Fancheng and went north after Guan Yu flooded the Seventh Army, The Cao army in Xiangyang quickly surrendered, and Guan Yu took Xiangfan lightly. He only had two months to complete a series of tasks such as reorganizing the army and horses, going north to besiege and capture Wancheng, which was obviously unlikely. After October, cao's reinforcements kept coming, and he not only had no chance to expand the results, but even it was difficult to keep the existing results.
Moreover, it should be noted that a very important reason for Guan Yu's final defeat was because Lü Meng took advantage of his Northern Expedition to attack Nan County and other places.
Lü Meng always believed that the Northern Expedition from Yangzhou would be difficult to defend even if Xuzhou was captured, and he always advocated the capture of Jingzhou to consolidate Jiangdong. His plan to capture Jingzhou was also approved by Sun Quan and implemented before Guan Yu flooded the Seventh Army.
Therefore, regardless of whether Guan Yu could capture Xiangyang and Fancheng, it would not change Lü Meng's plan to sneak into Jingzhou. Guan Yu, who had lost his rear base in this way, could not continue to the north, and had only two choices: staying in Xiangfan to wait for reinforcements and going south to retake Jingzhou.
Considering that Xiangyang and Fancheng were already in ruins after experiencing wars and floods, and that Cao Wei had even abandoned Xiangyang for a time in history, Guan Yu's stay in Xiangfan was difficult to get supplies, so this choice could be basically ruled out. And if Guan Yu leads his troops south, then it will be the same as in history, and it will be difficult to escape the result of the defeat and death of the soldiers.
Therefore, whether Guan Yu can capture Xiangyang and Fancheng is actually difficult to change the final result, and it will not have any impact on history.