The person who extended Cao Wei's life for four years was Cao Cao's descendant Cao Mao; his famous saying is: Sima Zhao's heart is known to everyone.
Cao Wei, the largest power in the world in the late Eastern Han Dynasty, was founded by Cao Cao, a famous military strategist, politician, and scholar. When Cao Cao was alive, the world was still under the Han Dynasty. After Cao Cao's death, his son Cao Pi forced Emperor Xian of Han to abdicate and established the Cao Wei regime. There were five emperors in the Cao Wei regime. Cao Mao was the fourth emperor and the only one who did not die well, because when he was in power, he coincided with the time when the Sima family was at its most ambitious.
Cao Mao, Cao Cao’s great-grandson and Cao Pi’s grandson, was smart, studious, and early in his career. When Cao Mao was thirteen years old, he was made emperor by Sima Shi. It is estimated that Sima Shi wanted to play this child as a puppet. But Sima Shi never expected that although the new emperor Cao Mao was young, he had high ambitions. He always took it as his own mission to restore Cao Wei's prestige and always governed personally. This made Sima Shi feel very uncomfortable.
Later Sima Shi died of illness, Sima Zhao began to take control of power, while Cao Mao's power became smaller and smaller. Seeing that the world conquered by his ancestors was about to be taken away by the Sima family. Cao Mao couldn't sit still anymore, so he summoned several of his confidants (all civil servants without combat effectiveness) to discuss a crusade against Sima Zhao. And said the famous saying: Sima Zhao's heart is known to everyone. However, the civil servants advised Cao Mao to be patient. After all, his power was too weak. But Cao Mao had made up his mind and threw the edict he had written on the ground, saying that he would risk his life to maintain the dignity of the royal family. So Cao Mao led a group of palace maids and eunuchs under him to kill Sima Zhao's mansion.
Think about it and you know the result. Cao Mao led a group of guys with close to zero combat effectiveness before they even got out of the imperial city gate. They were stopped by the Imperial Forest Army already controlled by the Sima clan. One of them was called Cheng. Ji's general acted like a fool and stabbed Emperor Cao Mao to death. Later, Sima Zhao came over after hearing the news. After pretending to cry a few times, he thought Cheng Ji was the mastermind of the regicide and killed him. Cheng Ji became the scapegoat.
After Cao Mao's death, Sima Zhao saw that a small number of people in the court were still loyal to Cao Wei, so he did not usurp the throne. Instead, he supported a new emperor, Cao Huan, which extended the life of the Cao Wei regime by another year. Click.