In 219, Guan Yu led most of the Jingzhou generals all the way north and besieged the two cities of Xiangfan. Although Cao Cao immediately sent Yu Ban's Seven Roads army to reinforce Fancheng, under Guan Yu's flooded Seven Army, Yu Ban had to surrender to Guan Yu, and for a time, Guan Yu's momentum shocked Huaxia, and the situation of the Northern Expedition of Shu Han was very good. However, at this time, Sun Quan sent Lü Meng to cross the river in white clothes and stab Guan Yu in the back. At that time, Lü Meng infiltrated jiangling city and forced the surrender of Taishou Mifang of Nan Commandery, at the same time, the Eastern Wu general Pan Zhang also wrote a letter to force Fu Shiren, who was sitting in the public security, to surrender, and the rear of Jingzhou fell. After that, Guan Yu had no way to retreat, and was captured by Eastern Wu on the way to choose a breakthrough, and was eventually killed.
From the perspective of strategic planning, Sun Quan's backstabbing Guan Yu is a complete misjudgment, after all, Lü Meng's goal is very clear, capturing Jingzhou is only the first step, his real goal is to control the Yangtze River, and the struggle between political groups is only to succeed in the king and defeat Kou, so whether Sun Quan backstabbed Guan Yu or not, as long as he has achieved something, naturally no one blames him. However, this plan to base all on the Yangtze River was declared a failure at the beginning, not to mention attacking Shu Han at this time, even after the Battle of Yiling, after the defeat of Shu Han, Eastern Wu failed to attack the White Emperor City, and even after the fall of Shu Han, Eastern Wu failed to achieve the possibility of dividing the world, which shows that Sun Quan's backstabbing Guan Yu itself is a great mistake. Since Sun Quan's backstabbing Guan Yu was the wrong decision, why was Eastern Wu not affected?
In fact, Sun Quan's wrong decision, the blow to Eastern Wu was very large, when Liu Bei's clique did not rise, Cao Wei's military pressure was completely concentrated on Sun Quan, and later Liu Bei's strength gradually increased, and after a large-scale Northern Expedition, the Cao Wei regime was tired of resistance, not only relaxed the pressure on the eastern front, but also transferred the defensive forces of Hefei, making Eastern Wu only need to attack Xuzhou to occupy the situation. However, after Sun Quan and Liu Bei had reached a stalemate, Cao Wei used a large number of troops against Sun Quan, and the flames of war had already reached Jiangnan.
It's just that Sun Quan was able to survive the crisis, on the one hand, relying on the green smoke from the ancestral tomb, on the second hand, Lu Xun's generals, and the third relying on Zhuge Liang's strategic determination. It should be known that the Shu Han Dynasty was tough on Wu as the mainstream, and if there was no Zhuge Liangli to exclude public opinion, if it were not for Zhuge Liang to think about the overall situation and abandon hatred, but insisted on avenging Liu Bei after restoring his strength, under the military pressure of Cao Wei and Shu Han, he was afraid that Sun Quan would not last long. If this were the case, Eastern Wu might have preceded the demise of the Shu Han Dynasty.
The author believes that Sun Quan's backstabbing Guan Yu undoubtedly brought him great harm, but there was Lu Xun inside Eastern Wu and Zhuge Liang inside Shu Han, and the two spared no effort to fill the pit dug by Sun Quan, which allowed Eastern Wu to survive this crisis.