Gaoping Tombs Incident

When Cao Rui became gravely ill, Sima Yi was named one of the regents for the young Cao Fang.

Emperor Ming made Cao Shuang Grand General, in charge of the court and of all forces, and had him share the regency for the young emperor with the Grand Commandant Sima Yi.

While the young emperor and Cao Shuang’s brothers were away at the Gaoping Tomb, Sima Yi mustered troops, seized the armory first, and camped at the Luo River pontoon bridge, sending up a memorial that accused Cao Shuang of betraying the testament and taking over the palace guard and key offices.

Sima Yi seized control in the Gaoping Tombs Incident and removed Cao Shuang’s faction; the coup reshaped Wei politics.

The Gaoping Tombs Incident was a political coup by Sima Yi against Cao Shuang, not a simple transfer of office.

Cao Shuang’s adviser Huan Fan urged him to take the emperor to Xuchang and call in outside troops, but Cao Shuang and his brothers hesitated, then sent envoys to admit fault to Sima Yi; they were dismissed from office and sent home as marquises.

Pei Songzhi quotes the Shi Yu, which says Sima Yi had Yin Damu, an officer Cao Shuang trusted, tell him that he would lose only his office, with an oath by the Luo River; Cao Shuang believed it and stood down his troops.

After the eunuch Zhang Dang testified that Cao Shuang, He Yan and others had planned a rebellion, officials judged the charge treason; Cao Shuang, his brothers, He Yan, Deng Yang, Ding Mi, Bi Gui, Li Sheng, Huan Fan and Zhang Dang were executed, and their families to the third degree.