As we all know, Liu Bei, Guan Yu, and Zhang Fei are the best brothers, they not only eat together, drink together, and cover the same bed when they sleep, from this point of view, they are definitely lifelong friendships. In addition, as brothers who fought together in the world, Liu Bei never had the slightest respect for Guan and Zhang, although on the surface, they were the relationship between the lord and the general, but privately, they were almost all called brothers, and even Zhuge Liang did not have such a special honor.
However, the bond between the three of them was cut off by Eastern Wu. In the twenty-fourth year of Jian'an (219), Cao Cao believed that Xuchang, where Emperor Xiandi of Han was located, was too close to where Guan Yu was stationed, so he had plans to move the capital. However, Sima Yi and others did not think so, and they suggested that Cao Cao and Sun Quan allied with him, and as long as Sun Quan agreed to sneak up on Guan Yu from behind, they agreed to divide the land of Jiangnan to him. At first, Sun Quan was not happy, and he wanted to make good friends with Guan Yu through marriage so that the two families could jointly resist Cao.
Unexpectedly, Guan Yu said that "the tiger girl can marry a dog", which directly offended Sun Quan. Enraged, Sun Quan decided to unite with Cao Cao and teach Guan Yu a lesson. Later, Sun Quan sent Lü Meng to surrender to Jingzhou, Guan Yu was rebelled by his subordinates, and Mi Fang, Shi Ren, and others were slow to send troops to support, resulting in his defeat of Maicheng and eventually being killed. Guan Yu's death greatly stimulated Liu Bei, and Eastern Wu killed not only one of his generals, but also his brother in life and death, and this vendetta was concluded in the end.
In 221, Liu Bei officially declared himself emperor, and he intended to retake Jingzhou and avenge Guan Yu. After hearing this news, Sun Quan sent people to seek peace at the first time, and Zhuge Jin analyzed the general situation of the world in detail in the letter, which roughly meant that Guan Yu's death would not rise to the height of war, because the strongest side was still Cao Wei, and Eastern Wu and Shu Han still needed to join forces. However, anger had already caused Liu Bei to lose his mind, and in July 221, he personally led a large army to attack Eastern Wu, and soon invaded Wu.
In fact, before that, Liu Bei had asked Zhang Fei to help, but he was killed by his men on the way to the rush, all of which was blamed on his bad habit of drunkenly whipping the soldiers. However, although Zhang Fei's death had already shown that this battle might be unfavorable, Liu Bei still did it without hesitation. In his opinion, whether it was Guan Yu or Zhang Fei, it was caused by Eastern Wu, and if they had not coveted the land of Jingzhou, they would not have come to this point. However, since Zhang Fei was dead, why didn't Liu Bei find Ma Chao to come to his aid?
Before the army was launched, Liu Bei had asked Zhuge Liang to guard Yizhou and Zhao Yun to guard Jiangzhou, and Ma Chao's role was not very large, and he could take it with him. However, he did not do this, he brought a group of new generals to the battle, and while training them, he also had the intention of protecting the veterans. The reason why he attacked Eastern Wu was entirely out of his own selfish interests and strategic incompatibility, and he did not want the elderly veterans to impulsively follow him. You know, at that time, Ma Chao was more than 50 years old, not only was he plagued by diseases, but even his combat strength had dropped by a large margin, and it was unwise to take him on a long-distance attack.
After the Battle of Yiling, Liu Bei's army was defeated, and those young generals gradually became the backbone of Shu Han after the baptism of fire. 5 years later, Zhuge Liang waved his army to the Northern Expedition, most of the generals he brought with him, they came back with Liu Bei, they increased their knowledge, accumulated experience, and became a major help for Zhuge Liang, until this time, he really understood Liu Bei's intentions.