The development of the Zen system to the Eastern Han Dynasty, Cao Wei and the Western Jin Dynasty was already a grandiose "routine" for usurpers of power, although it was imitating Yao Shun, but it was essentially the process of the conspirators usurping the throne of the previous dynasty. Cao Pi accepted the title of Emperor of Han Xian, and Sima Yan accepted Emperor Zen of Wei Yuan to be made emperor, all in the same way.
Forty-five years after the Cao Wei Dynasty, the Zen system was revived, which is why Cao Wei was replaced by the Western Jin Dynasty.
The reason why After Cao Pi accepted Zen concessions, only forty-five years, Sima Yan forced Emperor Zen concessions of Wei Yuan, which was related to the development of the Cao Wei regime itself, although there were many factors that led to this result, but there were several main reasons:
After Cao Pi ascended the throne, he suppressed the Cao clan relatives
After Cao Pi ascended the throne, in order to avoid the local division of forces at the end of the Eastern Han Dynasty, he restricted the power of Cao clan clan while dividing the Cao clan relatives. The clan relatives were divided into localities, but the Cao clan was not given the local management power and local military power, and Cao Wei's military power was in the central government.
Cao Pi
Although it was Cao Pi's own consideration of strengthening the centralization of power, it also led to the fact that once the center was controlled, the local government had no military power to use and could not defend the center. As a result, when Sima Shi was finally in charge of the Cao Wei Dynasty, he relied on the central center to govern the national military power, and the local Cao clan relatives could not form an effective resistance, which also led to the seizure of the Cao power by Sima Shi.
Cao Wei's special system of electing officials led to the power of the regime being overridden by the warriors
Cao Pi accepted the suggestion of Chen Qun and others and implemented the Nine Pins Zhongzheng System Election Law in Cao Wei, which led to a large number of local scholars in the Cao Wei regime, and gradually formed a situation in which Cao Wei's real power was overshadowed by the scholars.
Cao Rui
Although Cao Pi originally wanted to rely on the Jiupin Zhongzheng system to strengthen the connection between the Cao clan and the local shi clan, and intended to use the power of the shi clan to stabilize its own imperial power, he did not expect the shi clan to develop and grow, and families such as the Sima clan gradually lost control.
Problems arose in the Cao clan's inheritance, leading to the seizure of power by the courtiers
When the Cao Wei regime was in Cao Pi, Cao Pi monopolized power, and Cao Wei developed and grew; after Cao Rui succeeded to the throne, he appointed Sima Yi and others to fight against Shu Han and Eastern Wu, and The political situation of Cao Wei was still relatively stable; but after Cao Rui's death, Cao Fang succeeded to the throne, assisted the government Cao Shuang and monopolized power, causing the suppressed Sima Yi to counterattack, launch the Gaopingling Rebellion, and finally take over the military and political power of Cao Wei.
Since then, the actual control of the Cao Wei Dynasty has been transferred from the Cao clan to the hands of the Sima clan, and with the preparation of Sima Yi, Sima Shi, and Sima Zhao, after Sima Zhao's death, Sima Yan waited for the opportunity to usurp the throne and forced Emperor Wei to take the throne.
The reason why Cao Wei had to surrender his imperial power after forty-five years of accepting the throne of the Han Emperor was actually manifold, but in the end it was caused by the shortcomings of the Cao Wei regime itself.