The idiom "Sima Zhao's heart, known to passers-by" means that the conspirator's ambition is very obvious, and has reached the point where everyone knows it. The allusion to the idiom comes from the Cao Wei regime during the Three Kingdoms period.
Cao Xian, the fourth emperor of Cao Wei, had his grandfather being Cao Pi, the Emperor of Wei, and his father being Cao Lin, the King of the East China Sea. He was intelligent and studious from an early age, and at the age of 3 he was made a noble township prince. All along, there have been people who covet the world of the Cao family, and this family is the Sima family. After the Wei Ming Emperor Cao Rui entrusted Cao Shuang and Sima Yi to assist Cao Shuang before his death, the two squeezed each other out for power. After a fierce battle, Sima Yi became the one who laughed to the end. He killed Cao Shuang's party, and from then on Sima Shi took control of the military and political power of the State of Wei.
Perhaps worried about the criticism of the people of the world, even though Sima Yi had ambitions to usurp the throne, he did not act directly, but just wanted to do his best to grasp the power. Soon after Sima Yi's death, his eldest son Sima Shi deposed Cao Fang, who had become an adult but had not been pro-government, and installed Cao Fang, who was only 13 years old, as emperor. Obviously, Cao Xian was only a puppet emperor, and the power was still in the hands of the Sima clan. Sima Shi further expanded his power on the basis of his father. It wasn't long before he fell ill and died. When he was seriously ill, he gave all power to his younger brother Sima Zhao.
After Sima Zhao took over the throne, his ambitions grew, and he always wanted to replace Cao Xian and ascend to the emperor's throne himself. On the other hand, although Cao Xian is not very old, he can write and fight. Sima Shi's monopoly has been in power for decades, and it is obvious that the ancestors of the Cao family have worked hard to fight down the Jiangshan, why should they give it to others? He was very dissatisfied with Sima Shi's monopoly of power. His power and power were diminishing day by day, and he was not willing to be a puppet emperor. Moreover, Sima Zhao would not let himself go in the future. Therefore, he decided to preemptively attack Sima Zhao. It is worth mentioning that Cao Xian was the first emperor in the history of our country to go shirtless and personally assassinate his courtiers.
On the sixth night of the first month of May of the fifth year of Ganlu, Cao Xian summoned his close servants Li Zhao, Huangmen Congguan Jiaobo, and others into the palace to discuss the rebellion against Sima Zhao, and arranged the troops. He said: "Sima Zhao's ambitions are known even to pedestrians on the road. I can't sit still, I will personally go with you to fight Sima Zhao! King Shangshu did not approve of his approach, and persuaded: "Sima Shi's monopoly of power is not a day or two, and the whole court obeys his orders." The strength of the army in The hands of His Majesty is very weak, and the calamity is difficult to predict, please think twice! Cao Xian replied, "It was so decided, even if you die, what is so terrible?" Not to mention that you don't necessarily die! ”
Who knew that Wang Shen and Wang Ye, who were present, secretly informed Sima Zhao of Cao's plan and made him ready. The next day, when Cao Xian went out of the palace with the palace guards and slaves to fight Sima Zhao, he was ambushed by Sima Zhao's younger brother Sima Ling at the East Gate. The people around Cao Xi angrily rebuked Sima Ling, and his soldiers were frightened and fled. At this time, Sima Zhao's other forces, Cheng Ji and Jia Chong, arrived with troops and fought against Cao Xian face to face. Cao Xi personally fought the rebels and killed several rebels.
When the enemy army was about to be defeated, Jia Chong shouted, "The reason why Sima Gong raised you is because today, it is time for you to repay him!" Therefore, Cheng Ji immediately went forward to fight with Cao Xian. In the end, Cao Xian was killed by Cheng Ji under the car, at the age of 19. This is the origin of "Sima Zhao's heart, known to everyone".