The Meridian Valley Conspiracy is a mystery of the Three Kingdoms era. Many people believe that when Wei Yan proposed the Meridian Valley plot, Zhuge Liang arbitrarily denied it, missed the best opportunity to occupy Chang'an by surprise, and from then on, the Northern Expedition of Shu Han fell into strategic passivity, and even if Zhuge Liang was brilliant in tactics, he could not reverse the strategic decline. Considering the novel's section about Wei Yan's "anti-bone behind his head", this can't help but make many people in later generations think that Zhuge Liang denied the Meridian Valley conspiracy because he did not trust Wei Yan. So, is this really the case?
In fact, this is wronged Zhuge Liang. Because according to the records of the zhengshi, Zhuge Liang and Wei Yan did not have much intersection before Liu Bei's death. Wei Yan's position at that time was Hanzhong Taishou, single-mindedly building a defensive system in Hanzhong and guarding the northern gate of the Shu Han Dynasty. Zhuge Liang, on the other hand, accepted the heavy responsibility of the White Emperor's city and put all his energy into the construction of internal affairs. It can be said that Wei Yan and Zhuge Liang worked together to restore the Shu Han Dynasty from its decline after the defeat of Yiling. Although there has been no intersection for many years, they should all appreciate each other and have no hatred.
As for the several Northern Expedition wars, Wei Yan also gained Zhuge Liang's trust. Either it was to charge into the front, as the vanguard of the Northern Expedition to attack the city strategically, or it was arranged by Zhuge Liang to carry out the raiding mission, and made a lot of battle achievements. Even when Zhuge Liang was on the verge of death, he ordered wei yan to be cut off. You must know how important it is for an army to break the queen, which is to give the life of the Shu Han army to Wei Yan. Such trust is beyond words. Therefore, Zhuge Liang could not have denied his Meridian Valley plot because he did not trust Wei Yan.
Then, since Wei Yan had military talent, zhuge Liang was also very relieved about him, why did he not support Wei Yan's surprise attack plan? The reason is very simple - the Shu state is weak and weak, and it cannot afford to gamble at all. The Miracle of the Meridian Valley seems to be a surprise attack by Wei Yan's 10,000 troops, but the follow-up needs Zhuge Liang to lead the main army to Chang'an to cooperate together. Otherwise, even if the Meridian Valley surprise attack could be successful, Wei Yan would not be able to defend the city. So, it's a completely military adventure.
And what is Zhuge Liang's personality? Caution and prudence would rather not succeed, but never make mistakes. Many people may say that such a character suffered losses in the heavily gamblers of the Northern Expedition. Because the national strength of the Shu state was so weak at that time, it was only possible to succeed by military adventure. Perhaps, that's right. But the problem is that Zhuge Liang, as the head of the Shu Han Dynasty, he really can't afford to gamble. If the gamble is lost, not only will he bear the insult of the wrong country, but also let the Shu Han Dynasty that Liu Bei has worked so hard to create collapse in an instant. This tragic price was unbearable for Zhuge Liang.
In fact, this is the unfairness of fate. In the later Cao Wei war against Shu, Deng Ai carried out a surprise attack that was many times more extreme than the Meridian Valley Conspiracy, and immediately forced Liu Chan to surrender. The reason why Deng Ai dared to do this was because the Cao Wei clique was strong at that time, and the loss of tens of thousands of troops did not matter. Therefore, if he changed his position and let Zhuge Liang take charge of Cao Wei, then he might come up with a more aggressive offensive tactic than the Meridian Valley Plot, and shu Han and Eastern Wu would have been wiped out by then.