In the sixth year of Jianxing (228), Zhuge Liang sent troops from Hanzhong to attack Cao Wei. Earlier, the www.biquge.info Shu State discussed this matter, and Wei Yan, the assassin of Liangzhou, proposed the plan of Meridian Valley, trying to directly send troops to capture Chang'an, and Zhuge Liang considered it, vetoed this plan, but adopted a steady and steady strategy.

【Xiahou Nanqi people】

Xiahou Nan was the son of Xiahou Xuan, and was close and friendly to Emperor Wen of Wei, Cao Pi, when he was young. In the first year of the early Huang Dynasty (220), Cao Pi ascended the throne by Chan, established the Wei State, appointed Xiahou Nan as the general of Anxi, held the festival, and succeeded Xiahou Yuan to supervise Guanzhong and garrison Chang'an.

According to the record of "Wei Luo", the word Zilin is also a Zhongzi. Emperor Wen Shao and Nanqin, and ascended the throne, thinking that the general of Anxi, holding the festival, and inheriting Xiahou Yuan were all supervised in Guanzhong. There is no martial strategy in the nature of the long, but it is easy to govern life. In the second year of Taihe, Emperor Ming went west, and people had white trees, so they were called back to Shangshu.

Overall, although Xiahou Nan was in Chang'an at that time, as the son-in-law of Emperor Wen, he actually did not have much military merit, and basically relied on relationships to get on the throne.

【Meridian Valley Conspiracy】

During Zhuge Liang's Northern Expedition, Wei Yan was one of the important generals under his command, and every time he accompanied the army on the Northern Expedition, he asked Zhuge Liang to give him the command of 10,000 soldiers, and went all the way to tackle the key problems, and finally joined Zhuge Liang in Tongguan, just like the example of the former Han general Han Xin, but Zhuge Liang has not allowed it, so Wei Yan often said that Zhuge Liang was timid and hated that his talents could not be fully used.

According to the "Wei Luo", Zhuge Liang was about to attack Wei and discuss this military operation with others. Prime Minister Sima Wei Yan said: "I heard that Xiahou is the son-in-law of Emperor Wei, but this person is brave but not resourceful. Now please give me an elite army of 5,000 people, with 5,000 rations, directly from Baozhong, along the Qinling Mountains to the east, to the meridian road and turn to the north, in less than ten days, you can reach Chang'an. When Xiahou heard that I had suddenly arrived, he must have abandoned the city and fled. In Chang'an City, there are only Yushi and Jingzhao Taishou. The grain stored in the Hengmen granary and the food left over from the escape of the people were enough to supply the army. It will take more than twenty days for Wei to gather troops in the east, and you can reach it when you come out of the valley to meet you. In this way, the area west of Xianyang can be pacified in one fell swoop. Zhuge Liang thinks that this is a dangerous and inappropriate strategy, it is better to go out safely from the flat road, you can steadily obtain the Longyou region, and you can win with 100% certainty without losing, so you don't need Wei Yan's plan.

That is to say, there are two versions of the Meridian Valley conspiracy strictly speaking, one out of the Meridian Valley to capture Chang'an, and the other out of the Meridian Valley to capture Tongguan, which seems to be similar, but in fact there are still slight differences.

Chang'an is the old capital of the Han Dynasty, one of the most important cities at that time, and Tongguan is the necessary passage between Guanzhong and Luoyang.

[Too many variables, too high risk]

If Wei Yan's strategy succeeds, the benefits are very high, and he can basically seize the Yong and Liang states in the west of Cao Wei at one time. And the reason why Zhuge Liang didn't use Wei Yan's strategy was not that he didn't know the benefits of success, but because the risk of Meridian Valley's strategy was too high and there were too many variables, which had exceeded Zhuge Liang's ability to bear.

First of all, the Meridian Valley is not easy to go, although Shu Han did not send troops from the Meridian Valley at that time, but Cao Zhen did this in the later period, he led the army from the Meridian Valley to attack Hanzhong, only half of the journey was taken in a month, and finally gave up halfway, which shows the difficulty of sending troops from the Meridian Valley.

At that time, the Guanzhong area was centered on Chang'an, and after the Hangu Pass was abandoned in the east, Tongguan was the east gate, connecting Luo, the capital of the Wei Dynasty, and Yang was connected to Wuguan as the south gate, connecting Nanyang, Jingzhou. Therefore, if Shu Han wants to seize Guanzhong, Chang'an, Tongguan, and Wuguan are the most important.

Earlier, the commander of Chang'an, Xiahou Nan, was indeed just a child of a family and may not be very capable, but Wei Yan led the troops out of the Meridian Valley, and when the troops and supplies were not much, and the Meridian Valley was still in a treacherous environment, if Wei Yan wanted to successfully capture Chang'an, he had to count on Xiahou Nan to flee without a fight, and leave food and grass supplies, so that Wei Yan could easily enter Chang'an.

But what if Xiahou didn't escape? In the final analysis, Xiahou Nan was also born in a martial arts family, his father Xiahou Mao also fought with Cao Cao since he was a child, even if he had never seen a pig run, he had also eaten pork, Xiahou Nan had at least basic military knowledge in military affairs, and no matter what that day, the responsibility of defending the land was clearly written, if he dared to abandon the city and flee, what would be the consequences, Xiahou Nan definitely knew in his heart, and Chang'an was very close to Luoyang, and he would soon be able to get reinforcements. Xiahou Mao does have the possibility of escaping, but how high can it be? People may not be strong, but they are not stupid!

However, even if Xiahou Nan runs away, Chang'an may not be guarded, the high-ranking officials in Chang'an City are not Xiahou Nan, there are still lieutenants, eunuchs and the like, and Chang'an is so big, there will always be some people of insight, Wei Yan wants to conquer Chang'an in the short term, the difficulty is not too high.

And it may not be useful to just lay down Chang'an, as long as Tongguan and Wuguan are still in the hands of Cao Wei, then the Wei army can counterattack at any time, and the Shu army has no foundation in Yongzhou, even if Zhuge Liang supports in time, he has to fight a decisive battle with Cao Wei in Guanzhong.

Because the troops out of the Meridian Valley are limited, it is basically too late for Wei Yan to attack Chang'an first, and then attack Tongguan and Wuguan, and Wei Yan will give up Chang'an and not fight, and attack Tongguan or Wuguan first? Nor is it advisable. This is basically a dead end, without taking Chang'an, attacking Tongguan and other places, which is equivalent to directly handing over his back road to the Wei army, and Wei Yan is not Guan Yu, at that time Guan Yu dared to cross Xiangyang to directly attack Fancheng, relying on the water army, why did Wei Yan dare to directly ignore the threat of Chang'an, and when the time came, he was directly attacked by the east and west, and he was slow to die.

Chang'an, Tongguan and Wuguan form a triangular distribution in the pass, Chang'an is the seat of Yongzhou, Cao Wei is an important town, Tongguan communicates with Luoyang, and Cao Wei's new lord Cao Rui is not incompetent, Wuguan connects Jingzhou, Wancheng was garrisoned by Sima Yi at that time, Sima Yi eliminated Meng Da when he was in a hurry to march and hit Meng Da by surprise in a short period of time.

If you want to capture Guanzhong, you must occupy three places, just occupy Chang'an, no, wait to be drowned by Cao Wei's reinforcements; Directly hit Tongguan, no, wait to be cut off from the back road, and then be surrounded and annihilated by the east and west armies; Directly hit Wuguan, that is even more dead, the importance of Chang'an and Tongguan is higher than Wuguan, but can you ignore Wuguan, no, if you dare to ignore Wuguan, Sima Yi can send you directly to see the king of Hades.

To send troops from the Meridian Valley, the treacherous geographical environment and in order not to attract Cao Wei's attention, it is already doomed that there are not many troops, at most 10,000 people, but only relying on these troops to defeat Chang'an, Tongguan, Wuguan any place depends on luck, it is basically impossible to eat it all at once, and as long as one of these three places is not defeated, it may lead to a failure, so Zhuge Liang did not dare to take Wei Yan's strategy at all.

All in all, it is already up to the sky to send troops to Meridian Valley to capture any of Chang'an, Tongguan and Wuguan, and it is basically impossible to capture two, and three is a fool's dream.

And Zhuge Liang didn't take the Meridian Valley strategy at the beginning, let alone later, at that time, Cao Wei had greatly increased his attention to Shu Han, and the defense of Guanzhong was not comparable to the past, and the Meridian Valley conspiracy had no chance.