Incident at Gaoping Tombs

The Incident at Gaoping Tombs (高平陵之變) in 249 was a coup d'état that occurred in the state of Cao Wei during the Three Kingdoms period of Chinese history. The parties involved were Cao Shuang and Sima Yi. Sima Yi seized power during the coup and had Cao Shuang killed. The coup increased the Sima clan's power and influence in Wei, thus providing the foundation of the Jin Dynasty.

Background
In 239, Wei emperor Cao Rui died and was succeeded by the eight-year-old Cao Fang. In his final edict, Cao Rui named General-in-Chief Cao Shuang and Grand Commandant Sima Yi as the regents to assist Cao Fang in ruling Wei. Cao Shuang ostracised Sima Yi and placed his close associates such as He Yan, Deng Yang, Li Sheng (李勝), Bi Gui and Ding Mi (丁謐) in high positions in the Wei imperial court. Cao Shuang promoted Sima Yi to the rank of Grand Tutor, which was actually a move by Cao Shuang to place Sima Yi in a powerless position. Cao Shuang also appointed his brothers Cao Xi and Cao Xun (曹訓) in high military ranks. The imperial guards were also under Cao Shuang's command. Cao Shuang and his associates thus controlled the Wei court. Cao Shuang abused his power by indulging in personal entertainment while neglecting state affairs.

Sima Yi was in a powerless position and was thus unable to participate in discussions on state affairs. In 247, he feigned illness to avoid Cao Shuang and ostensibly retired from public life. The next year, when Li Sheng was sent to Jing Province to assume office as the new Inspector, he paid a visit to Sima Yi before his departure. Sima Yi put up a show in front of Li Sheng and pretended that his health had worsened. Sima Yi pretended to have poor hearing and misheard "Jing Province" as "Bing Province". Later, when a servant came to feed him porridge, Sima Yi pretended to cough so badly that the porridge spilt on his clothes. Li Sheng reported Sima Yi's condition to Cao Shuang and Cao Shuang thought that Sima Yi was going to die soon so he lowered his guard. In the meantime, Sima Yi and his sons Sima Shi and Sima Zhao were secretly preparing for a coup to seize power.

Course of events
In 249, Wei emperor Cao Fang visited the Gaoping Tombs to pay his respects to the late emperor Cao Rui. Cao Shuang, together with his brothers and close associates, followed Cao Fang on the trip. While they were away, Sima Yi seized the opportunity to launch the military coup. He had all the city gates in Luoyang shut on the orders of the empress dowager and he took over the floating bridge at the Luo River as well. He appointed Gao Rou as the acting General-in-Chief and Gao took over command of Cao Shuang's army, while Minister Coachman (太僕) Wang Guan (王觀) was placed in charge of Cao Xi's army. He wrote a report to Cao Fang, asking Cao Fang to remove Cao Shuang and his brothers from power, in the name of the Empress Dowager Guo. Cao Shuang was shocked when he saw the report and was unsure of how to react.

The Minister of Finance Huan Fan managed to flee from Luoyang and went to see Cao Shuang. Huan Fan advised Cao Shuang to move to Xuchang and call for a punitive war against Sima Yi in the name of the emperor. On the other hand, Palace Attendant Xu Yun (許允), Imperial Secretariat Chen Tai and Palace Guard Yin Damu (尹大目) advised Cao Shuang to surrender as soon as possible. Cao Shuang pondered over the issue for a night and finally decided to surrender. He hoped to lead a luxurious life even though he had lost his power. He requested for Cao Fang to strip him of his military post and then he sent Xu Yun and Chen Tai to apologize to Sima Yi on his behalf. Cao Shuang and his brothers returned to their residences after losing their powers.

Aftermath
After the incident, Zhang Dang (張當) was arrested and he produced a full confession on a plot to overthrow the emperor. Cao Shuang and his associates were accused of treason and arrested and thrown into prison. Huan Fan had earlier met Si Fan (司蕃) during his escape from Luoyang and he told Si Fan, "The Imperial Tutor is planning to rebel, you should come with me!" Si Fan surrendered himself to Sima Yi after that. Sima Yi had Huan Fan arrested and thrown into prison on charges of falsely accusing him of treason instead. Subsequently, Cao Shuang and his associates were executed for treason along with their clans.

Sima Yi successfully seized power during the coup and eliminated the royal faction led by Cao Shuang in the imperial court. He was appointed as chancellor and received the Nine Bestowments from the emperor Cao Fang. Sima Yi's sons Sima Shi and Sima Zhao were placed in high ranking positions in the Wei court as well.

In 251, Wang Ling and Linghu Yu (令狐愚) felt that Cao Fang was too young and weak to rule and that state power was actually in the hands of Sima Yi. They started a rebellion in Shouchun to overthrow Cao Fang and Sima Yi. They intended to install prince Cao Biao (曹彪) on the throne. Eventually, the rebellion was crushed by Sima Yi and the rebel leaders were killed.

After Sima Yi's death, his sons continued to control Wei and they eliminated almost all their political opponents. Eventually, the royal Cao family's influence in Wei weakened and in 265 Sima Zhao's son Sima Yan forced the last Wei ruler Cao Huan to abdicate and took over the throne, founding the Jin Dynasty.

Modern references
In the seventh installment of Koei's Dynasty Warriors video game series, a stage is dedicated to the initial coup d'etat against Cao Shuang, while the other two are mentioned in the narration. Cao Fang's visit to Gaoping Tombs wasn't mentioned in the game and was mentioned to be on a hunting trip with Cao Shuang.