Rock weather 30

There is a big mistake in this question. Jiang Wei's time in Hanzhong is not shorter than Wei Yan's, and the forms they face are different. In the final analysis, it is because Shu Han has been weak, and the main responsibility is not on Jiang Wei.

In fact, Jiang Wei spent more time in Hanzhong than Wei Yan did in AD 2 19. Liu Bei defeated Cao Cao and captured Hanzhong. In the autumn of the same year, Liu Bei promoted Wei Yan to be the general of Zhenyuan, the satrap of Hanzhong and the guardian of Hanzhong. In 227 AD, Zhuge Liang personally sat in Hanzhong to prepare for the Northern Expedition, and Wei Yan was the pioneer of the Northern Expedition. After that, Wei Yan was no longer in charge of Hanzhong defense until Zhuge Liang and Wei Yan died, so Wei Yan actually stayed in Hanzhong for a little over eight years.

In 238 AD, Jiang Wei and the general Jiang Wan were guarding Hanzhong for the first time. After Jiang Wan's death, he followed Fei Yi to Hanzhong. Until the assassination of Fei Yi in early AD 253, Jiang Wei was in charge of the military power of Shu Han, and Shu Han perished in AD 1 1. During this period, Jiang Wei was responsible for the defense of Hanzhong. Almost 1 1 year. In terms of time, Jiang Wei stayed in Hanzhong for two years longer than Wei Yan.

When Wei Yan was guarding Hanzhong, Shu Wei did not take this as the main direction. In addition, when Wei Yan was guarding Hanzhong, Wei never took military action against Hanzhong. This is not because Wei was afraid of Wei Yan. However, after the war in Hanzhong, the war in Xiangfan broke out immediately. Guan Yu led the army to the northern expedition to Xiangfan, and defeated Coss and Yu Ban successively. Cao Cao suffered heavy losses and once tried to move the capital to avoid Guan Yu's sharp edge, so he could not take the initiative to attack Hanzhong.

Later, although Guan was defeated by the attack on Jingzhou, Cao Cao did not die because of it. After Cao Pi succeeded to the throne, he was busy consolidating his position. In addition, during this period, Wei Shuwu shifted the focus of competition to Jingzhou, so there was no war on the Hanzhong-Guanzhong front. It was not until 228 AD that Zhuge Liang began his first Northern Expedition that Wei and Shu paid attention to Hanzhong-Guanzhong Line again.

When Wei attacked Hanzhong for the first time, it was not until 230 AD that Cao Zhen fell into Shu. As a result, because of the bad weather and continuous rain, Wei Jun was soaked in rain for more than a month, and it was difficult to move forward. It ended in failure before it touched the Hanzhong defense line. Although Wei Yan and Wu Yi defeated Fei Yao and Guo Huai in Yangxi in this campaign, Zhuge Liang himself presided over the defense of Hanzhong, no matter what Wei Yan did.

Jiang Wei's failure is mainly due to the decline of Shu Han's national strength and Liu Chan's fatuity. During Jiang Wei's guarding period, he still held the initiative in Hanzhong-Guanzhong area for a long time and made many northern expeditions. However, in the late Shu-Han period, Liu Chan prized Huang Hao, and with the power struggle within Shu-Han, Jiang Wei had to open up wasteland in the stack. Before Zhong Hui attacked Shu, Jiang Wei wrote a warning, hoping to strengthen the defense of Yang 'an Pass and Yin Pingqiao as soon as possible, but it didn't attract much attention.

As a result, Wei Jun attacked and surrounded Seoul and Lecheng. When Wei Jun attacked Yangpingguan, the garrison commander Jiang Shu defected again, which led to Fu Qian's death and the fall of Yangpingguan. It only took Wei Jun a month to capture Hanzhong. Therefore, Jiang Wei's failure is mainly due to political factors. Liu Chan's fatuity and the decline of Shu Han were not caused by Jiang Wei's poor command. At this time, even if Wei Yanshou changed to Hanzhong, he would still fail.