From the spring of 228 to the winter of 234, Zhuge Liang sent troops to Hanzhong to help the Han Dynasty unify the Central Plains. Seven years later, he launched five wars against Cao Wei. However, several northern expeditions had little effect and wasted human and financial resources. In that case, why didn't Zhuge Liang take a rest, save his strength and rush to the Northern Expedition? A man as powerful as Zhuge Liang is sure to know the seriousness of it, so why on earth did he insist on the constant Northern Expedition?

First, fulfill Liu Bei's wish. "A Model" is a form written by Zhuge Liang to his late master Liu Chan during his Northern Expedition, from which we can see that Zhuge Liang's Northern Expedition was to repay the kindness of the former emperor Liu Bei and fulfill his last wish of recovering the Han Dynasty. Moreover, Shu Han's northern expedition was a well-known just move, which not only made no mistakes politically, but also continued to form an alliance with Soochow, so Shu Han could only make the northern expedition at that time.

Second, the situation forced. For Shu Han, the steep mountain range is undoubtedly a natural barrier, but it also has disadvantages, that is, if you rest, you can only eat your old money. And Cao Rui has taken a fortress in Shu, which has greatly restored the strength of Wei. When Shu and Han are developing, the national strength of Cao and Wei will develop faster, so the gap between Han and Wei will become bigger and bigger. Once Cao Wei's national strength is strong, Shu can only do nothing. Therefore, if Shu Han and Cao Wei are deadlocked in the future, the rear will definitely be dragged to death, and they can only surrender when the soldiers, money and people are in dire straits. Therefore, Zhuge Liang's decision on the Northern Expedition was based on an accurate judgment of the overall situation, and he insisted on the Northern Expedition. If he doesn't go north, he can only do nothing.

Third, transfer internal contradictions. After Liu Bei's death, there were many internal contradictions in Shu Han, which can be divided into three camps: Jingzhou camp, Eastern Zhou camp and Shu indigenous camp. At first, the contradiction could be reconciled, but after Guan Yu lost Jingzhou and Liu Bei lost Yiling, the situation of these three camps became dominated by Jingzhou camp, and the Eastern Zhou camp was jointly wooed, and the indigenous camp in Shu was squeezed out and suppressed. Liu Bei made such a strategy clear when he entrusted orphans. However, after Jingzhou camp, the elders suffered heavy casualties and could no longer suppress the powerful Sichuan indigenous camp. Therefore, the Northern Expedition can transfer the internal contradictions of Shu and Han to the external contradictions of Cao and Wei, and at the same time expand the territory. The best result may be to unify the Central Plains and restore the Han family. Why not?