In fact, the development of Shu Han was smooth in the early days, and its slogan was also loud: Han thieves strive for each other and are not biased. At that time, the momentum of Shu Han was also very strong. It can be said that Cao Wei had to avoid its sharpness, but the extremes meet. When Lu Xun of Soochow began to take to the stage, he offered Sun Quan. Guan Yu not only lost Jingzhou because of carelessness, but also sent himself to a dead end.

From this point, Shu Han began to decline. Not only did the development of materials become very slow, but if he wanted to attack Wu Dong and Cao Wei, he needed more preparation and a longer journey. After that, Liu Bei was too impatient. After being defeated by Lu Xun, he was entrusted to Baidicheng.

At this time, Zhuge Liang took on the heavy responsibility. On the one hand, he must stabilize the interior of Shu and Han and prevent internal differentiation. At the same time, on the one hand, he should ensure the development of Shu Han, on the other hand, he should guard against the attacks of Dongwu and Cao Wei. After consolidating internal affairs, we can only choose the Northern Expedition.

First, the Northern Expedition was Liu Bei's last wish. If you only care about yourself, you will inevitably be opposed by Liu Bei's old men. Moreover, Jingzhou School was stationed in Yizhou at that time, and Yizhou was full of talents. If Zhuge Liang had not gone to the Northern Expedition, the Yizhou faction would certainly not agree to let Zhuge Liang take power again.

Second, if we don't send troops to the Northern Expedition, the previous slogan will be invalid, so that the people of the world will not turn to Shu Han again. Even if Shu Han is an orthodox Han family, if we don't carry out our own tasks, then Shu Han will have no orthodox significance.

Third, if you only care about your own development, you can't beat Wu Dong, let alone Cao Wei. Because Shu Han's resources are limited and Wu Dong is rich, Cao Wei has a large territory and develops faster than Shu Han.