From an early age, Sima Yi was intelligent and strategic, erudite and knowledgeable, and subservient to Confucianism. Because Cao Cao was born into a "castrated and ugly legacy", Sima Yi once refused to be granted an official position by Cao Cao. By 208, after Cao Cao became chancellor, he forcibly requisitioned Sima Yi as a literary warrior.
Eight years later, the alliance between the Shu and Wu states broke down, and Sun Quan was attacked by Liu Bei. In order to avoid being robbed by Cao Cao, Sun Quan declared himself a vassal to Cao Cao, not only submitting to him, but also supporting Cao cao to replace the Han Dynasty and establish himself.
Cao Cao believed that Sun Quan was doing this to make himself the target of everyone, but Sima Yi said: "The number of Great Han Qi has been exhausted, you can subdue people with virtue, and at the same time, Sun Quan is a subject to you, which can be said to be providence." Therefore, Sima Yi showed his support for Cao's replacement of the Han, and as a result, Cao Cao trusted him more.
After Cao Cao became the King of Wei, Sima Yi repeatedly contributed good strategies and tried his best to assist Cao Cao. For example, when Guan Yu attacked Fancheng, as a general of the Shu state, he was mighty and powerful. In order to avoid Guan Yu's pursuit and avoid his attack, Cao Cao wanted to relocate the capital to Hebei, but Sima Yi strongly discouraged it, believing: "If you move the capital now, it will not only show weakness to the enemy, but also make the hearts of the people in the country float." Therefore, the best way is to persuade Sun Quan to attack Guan Yu's back road and attack on both sides, which can relieve Fan Cheng's crisis. ”
After that, Cao Cao felt that Sima Yi's words were reasonable, so he adopted his strategy. Later, Sun Quan agreed to this practice, and from the Gangneung area, he had the general Lü Meng round up and kill Guan Yu. As the saying goes, the sandpipers competed for fishing and profit, and Sima Yi cleverly took advantage of the contradiction between Sun Quan and Liu Bei's seizure of Jingzhou, not only attacking Guan Yu in this battle, relieving Fancheng of the trouble, but also allowing Zhuge Liang's plan to attack zhongyuan from both wanluo and Qinchuan in two ways completely failed.
Starting with The Wei Emperor Cao Pi, Sima Yi almost became the patron saint of Cao Wei's army, and no matter which way the strong enemy came, he would use his own tricks to turn the danger into a disaster. Of all his military achievements, two were the most important:
First, it restricted Zhuge Liang's attack;
The second was to quell the rebellion of Gongsun Yuan, the Taishou of Liaodong Province.
And that year, he was already a 61-year-old man.
However, due to orthodoxy and the constraints of morality, successive monarchs have explained Too much about Sima Yi's treachery, blindly accusing him of disloyalty, but failing to reflect on Cao Cao's repeated suspicions of him, resulting in distrust between the monarchs and courtiers, and eventually, there was a discord between the monarchs and courtiers.
Cao Cao's suspicions had always been there, not only at Sima Yi alone.
Although Cao Cao knows and uses talents, there is an important premise, that is, he must be used for his own use and under his control, otherwise, this person must be eliminated. Cao Cao roughly loved and hated Sima Yi's talents, of course, he was impressed by his talents, and his hatred was the fear that after a hundred years, his descendants would not be able to control Sima Yi and would probably be usurped by him.
Therefore, Cao Cao once reminded his son Cao Pi that Sima Yi was not a reliable courtier, and that he might interfere in the affairs of the government, and asked him to be careful of this person.
However, Cao Pi not only did not listen to his father's advice, but also entrusted Sima Yi with a heavy responsibility. In addition, Cao Pi also said that Sima Yi would be loyal to himself, just as Xiao He treated Liu Bang. Before his death, Cao Pi repeatedly instructed his son Cao Rui, that is, the crown prince: "There are three people that you can safely appoint, no doubt, they are Cao Zhen, Chen Qun and Sima Yi." ”
The reason why Cao Zhen trusted was because he was a member of the royal family and a member of his own family, although he was only slightly mediocre, but he was loyal and commendable, and he was a trustworthy person. Chen Qun was mainly in charge of government affairs, so only Sima Yi had superior strategy and military leadership among these three people. But, as a royal family, how can you completely trust a person with a foreign surname?
The suspicion of Sima Yi by the imperial family members in the imperial court was everywhere, which put Emperor Wei Ming in a dilemma, and it was difficult for him to decide whether to believe or not to believe. Sima Yi recruited Gongsun Yuan and passed through his hometown of Wen County on the way, during which time he not only did not feel honored because of his status at that time, but did not have the feeling of returning to his hometown, but instead had the desolation of returning to his hometown.
Because, he knew in his heart that after destroying Gongsun Yuan, he didn't know whether he could get a good death. Since ancient times, it has been a cunning rabbit dead dog cooking, so Sima Yi is very worried about his future. However, Sima Yi was destined to be a minister appointed by Heaven. On his way back to the dynasty, Emperor Ming of Wei suddenly fell seriously ill, and at that time, his son Cao Fang was only eight years old.
When Sima Yi heard the news, he traveled day and night, and rushed to Kyoto one night. Sima Yi saw Emperor Wei Ming weeping bitterly and inquiring about his condition, and Emperor Wei Wendi replied, "I have not died, that is, I want to wait for you to return, and now that I see you, there is no regret, my son will entrust it to you, please take good care of him." Although Emperor Wei Ming had a dying edict for Sima Yi, Cao Shuang did not buy it.
After that, he also wanted to use the strength of the royal family members to exclude Sima Yi. After that, Sima Yi said that he had to go home to recuperate from his illness and never asked about political affairs. However, Cao Shuang was worried that he was pretending to be ill, so he sent someone to spy on Sima Yi's health. Sima Yi knew what the visitor meant, and pretended to be ill to deceive Cao Shuang's eyeliner. From then on, Cao Shuang no longer had any precautions against Sima Yi.
In 249, taking advantage of the opportunity for the Wei emperor Cao Fang and the general Cao Shuang to leave Luoyang to worship Emperor Wei Ming, Sima Yi quickly attacked and eliminated all of Cao Shuang's forces. From then on, Cao Wei's military and political power was in the hands of Sima Yi, laying the foundation for Sima Shi's final unification of the world.
In fact, Sima Yi had been a vassal of the State of Wei all his life, and he could be regarded as abiding by the feelings of the three emperors of the State of Wei.
Resources:
[Romance of the Three Kingdoms, Wei Shu, Emperor WuJi I, Jin Shu, Emperor Xuandi Ji, Three Kingdoms Chronicles, Wu Shu, Wu Zhuan II]