The "Meridian Valley Conspiracy" proposed by Wei Yan is an old topic. However, there are two versions of the "Meridian Valley Conspiracy": One is recorded by wei Luo: Wei Yan led 5,000 elite soldiers from the Meridian Valley, quickly attacked Chang'an and held out for more than 20 days, waiting for Zhuge Liang to lead the main force out of the Valley to meet, and then took the Guanzhong region west of Xianyang in one fell swoop.
Second, the "Chronicle of the Three Kingdoms and the Biography of Wei Yan" records that instead of attacking Chang'an, Wei Yan led his army to seize the two natural passes of Tongguan and Wuguan, kept the reinforcements transferred by Cao Wei from the Central Plains out of Guanguan, cut off the connection between inside and outside Tongguan, and led the main force led by Zhuge Liang to sweep away the main force of Cao Wei's army stationed in Guanzhong, and then occupy the entire Guanzhong.
For a long time, most of the discussions were contained in the first version of wei luo, that is, the occupation of Chang'an as the ultimate goal. In this version, Wei Yan believed that Xiahou Shu, who was guarding Chang'an, was a second-generation official who was eating and waiting for death, and when he saw the divine soldiers descending from heaven, he would inevitably turn around and scurry around, and there were no outstanding officials in Chang'an City, and Guanzhong was heavy, with grain and grass supplies, and he would be able to hold out for some time, and when the army arrived, the great cause could be determined.
Many people say that if Zhuge Liang had adopted Wei Yan's suggestion, it is likely that the Northern Expedition would have been successful long ago, but if he really operated according to the first version, Wei Yan would have lost.
First of all, this road in the Meridian Valley was not a secret path, but a well-known road, and Wei Yan wanted to launch a surprise attack through this road, which was easy to be guessed or explored by Wei Jun. The Wei army could set up an ambush at any place in any valley, or it could wait at the mouth of the valley to wait for labor and wait in a strict position, and Wei Yan and the troops led by him would surely die without a corpse.
Second, the war was full of uncertainty, even if Wei Yan rushed out of the Meridian Valley and made a surprise attack under Chang'an City, if the Chang'an defender could not hold out and launched the people to defend the city, Wei Yan would delay under the city for a few days, and it would still be the end of the entire army. Or if Wei Yan captured Chang'an, would Zhuge Liang's army arrive as scheduled? When Cao Wei received the news of the fall of Chang'an, he was bound to fight to the death to block Zhuge Liang's army. Wei Yan became a lone army deep, how many days could he hold out under the siege of Cao Wei?
In 1636, more than 1400 years after Wei Yan proposed the "Meridian Valley Conspiracy", a famous battle witnessed the horror of the Meridian Valley. At the end of the Ming Dynasty, the famous leader of the peasant uprising, Gao Yingxiang, the "King of Chuang", led an army of 50,000 to practice the "Meridian Valley Miracle". In 1636, Gao Yingxiang left Hanzhong and planned to march into Shaanxi and capture Xi'an. Because he was intercepted by Sun Chuanting, one of the five famous generals at the end of the Ming Dynasty, Gao Yingxiang suffered a loss, could not enter, and could not retreat, so he thought of the Meridian Valley.
Braving the heavy rain, Gao Yingxiang led the army into the Meridian Valley Trail. Unexpectedly, the road in the valley was too difficult to walk, and after walking for 15 days, Gao Yingxiang's army finally reached Heishuiyu, and the people were sleepy and tired. However, as long as you pass through here, the front can be directly approached by Xi'an. But what he didn't expect was that Sun Chuanting had already set up an ambush here. The two sides fought fiercely for four days, and Gao Yingxiang's 50,000 troops were easily surrounded and annihilated by Sun Chuanting. Gao Yingxiang was taken to Beijing, Where Ling Chi was executed, and the title of "King of Chuang" fell to Li Zicheng.
It can be seen that the "Meridian Valley Conspiracy" version of Wei Luo is not feasible, so what about the version recorded in the "Romance of the Three Kingdoms and The Biography of Wei Yan"? First of all, the answer, the feasibility is very high.
The whole process of the plan: Wei Yan led the Shu army to 10,000 elite soldiers (5,000 elite soldiers, 5,000 negative grain), marched along the Meridian Valley (faster), passed through Chang'an and other places but did not stop, went straight to Tongguan, seized this natural danger and held out for more than 20 days, only to wait for Zhuge Liang to lead the main force to come to the confluence. Along the way, the Cao Wei defenders in Chang'an and other places were too late to respond to this suddenly appearing army, and the first reaction must be to stick to the city, and when the two armies converged, the whole territory of Guanzhong would be owned by Shu, and the Northern Expedition would be a great success.
Of course, this plan also has prerequisites. First, the Shu army must move quickly and suddenly; second, Eastern Wu must cooperate; third, Wei Yan's 10,000 soldiers must fight quickly and quickly take Tongguan and Wuguan.
The first condition is not a problem. After Liu Bei's death, Shu Han recuperated for several years, and Cao Wei had much contempt for Shu Han, so that the defense of Guanzhong was insufficiently prepared, so as soon as the Shu army came, three counties immediately announced their surrender. The history books record: "The only one in the country is Liu Bei in Shu. Bei died, and the number of years was silent, and it was slightly unprepared; and the pawn smelled out, and the fear of the government and the opposition, especially LongYou and Qishan, so the three counties should be bright at the same time. ”
As long as there were no abnormal conditions in the Meridian Valley area when Wei Yan set out, such as heavy rainstorms and natural disasters, and it was possible to pass quickly, the tactical purpose of "suddenness" could be achieved completely.
The second condition, the State of Wu was supportive of the Shu Han Dynasty, Zhuge Liang was also very attentive to the diplomatic work of the State of Wu, and in the following northern expeditions, the State of Wu Zhuge Jin and Lu Xun also gave many cooperation, so this condition is not difficult to achieve.
The third condition is more difficult. Wei Yan only had 10,000 soldiers, and after a long-distance attack, he also had to quickly take down two natural danger passes and achieve the purpose of holding on, which showed the difficulty. However, wei Yan, as a battle-hardened general, was not stunned, and he should be very clear and sure of the difficulty of this battle, otherwise he would not have proposed this plan. Therefore, this condition was difficult, but Wei Yan was confident that he could do it.
In addition, Zhuge Liang's attitude in both versions can also illustrate some problems. Zhuge Liang's attitude toward version one is "thinking that this county is in danger; so there is no need to delay the calculation", which clearly gives the reason for not using this plan; while in version two, Zhuge Liang is "system and not allowed", and does not give a reason for not using it, which just shows that this version of the Meridian Valley conspiracy has not been completely denied, although the probability of success is not small, but the risk is equally high.
Wei Yan, a low-born, self-made person, has a gambler spirit, who is more able to take high risks and has few scruples. However, Zhuge Liang painstakingly managed the Shu Han up and down, and worked hard and diligently, lest there be a little mistake. He must control the risk within the scope that he can accept and deal with, and he has to consider the various effects brought about by the failure of the surprise attack, if there is a mistake, Zhuge Liang cannot accept it, he would rather take it step by step and fight steadily, because the Shu kingdom is too difficult, he is too difficult!
(References: Romance of the Three Kingdoms, Wei Luo, etc.)