Yu Jin is also a battle-hardened commander in chief. How did he lose the battle of Fancheng?
In the battle of Xiangfan, Cao Cao had just retreated from Hanzhong to Chang 'an, far away from Guanzhong. At that time, Xiangfan was guarded by Xiangyang satrap Lu Chang, Cheung Nam general Coss, Runa satrap Man Chong and others. Guan Yu took Coss as the commander in chief, repelled Coss, Lu Chang and Man Chong, and surrounded Xiangyang City and Fancheng.
Xiangyang city is on the south bank of Hanshui River, and Fancheng is on the north bank of Hanshui River. Guan Yu's army attacking Xiangfan includes not only the army, but also the water army that Guan Yu trained for many years. With the cooperation of the water army, Guan Yu blocked the Hanshui River, which led to the isolation of Xiangyang and Fancheng.
In an emergency military situation, Cao Cao could only send General Zuo to lead the elite Central Army of the Seventh Army to reinforce Xiangfan in the Forbidden City. The seven armies in the Forbidden City, with 30,000 men, are probably the elite central army left by Cao Wei in Xuchang and Luoyang, because the main force was taken away by Cao Cao, and there is no other army closer to Cao Wei except the reinforcements in the Forbidden City.
Moreover, Yu Jin has the right to fake festivals, which is given to Yu Jin. In an emergency, he can make some decisions on behalf of Cao Cao, for example, he can kill the rebels without informing Cao Cao.
In fact, in the north of Xiangfan, General Pound led the troops to confront Guan Yu. After the arrival of 30,000 troops of the Seventh Army in Yu Ban, Cao Wei's army occupied a numerical advantage. It happened in August, and it rained for many days in a row, and the Hanshui River soared. The fundamental reason why Yu Jin and Pound failed was that they camped in low-lying areas. After the Hanshui River surged, the flood flooded the camp of Yu Jin and Pound.
Yu Jin and Pound can only station troops on the highlands. Because Yu Jin did not have the cooperation of the water army, the whole army lost its combat effectiveness. At this time Guan Yu led the water army to attack Pound and Yujin. Pound and Yujin didn't have the strength to fight back at all, so they could only watch Guan Yu attack. There is no other way but to fight back with bows and arrows.
But soon, Guan Yu's water army surrounded Pound's Yu Jin. In desperation, Yu Jin surrendered with more than 30,000 people from seven armies. Pound refused to surrender and was killed by Guan Yu. The failure of Yu Jin and Pound is of course due to the weather, which is fair to both sides. Since Cao Jun occupied Xiangfan in 208 AD, Cao Jun has been in Xiangfan for 1 1 year, so he should be familiar with the weather in Xiangfan, but Yu Jin and Pound didn't realize this problem.
In addition, the flood caused by rain is definitely not caused in a short time. There is a process. Why can't we prepare in advance in the ban? It is impossible for Cao Wei to station in Xiangfan without a water army, otherwise the water army of Cao Wei will be destroyed by Guan Yu. In short, the failure of the ban is mainly due to two reasons:
First, personal military comprehensive command ability is not as good as Guan Yu.
Second, in the face of rain and the soaring Hanshui River, there is no solution.