A General in Exile: The Political Isolation of Sima Yi

In the second year of the Jingchu era (238 AD), four years after the pivotal Battle of Wuzhang Plains, Emperor Ming of Wei summoned the formidable Sima Yi to the capital Luoyang. At the time, Sima Yi was stationed near Chang’an, ostensibly to guard against potential northern expeditions by Shu Han. However, the court’s true motive was more calculated: keeping this increasingly powerful figure away from the political heartland.

Emperor Ming’s reasoning was strategic: “To suppress Gongsun Yuan’s rebellion in Liaodong, we must rely on Sima Yi. Guanqiu Jian’s failures prove this task exceeds his capabilities.” Thus began a carefully orchestrated political dance—promoting Sima Yi to Grand Commandant (Minister of Defense) while subtly stripping him of direct military influence by leaving the position of Grand General vacant. The appointment was neither outright promotion nor demotion but a masterstroke in bureaucratic containment.

The Liaodong Campaign: Military Genius Amidst Monsoons

Tasked with leading 40,000 troops against the self-proclaimed “King of Yan” Gongsun Yuan, Sima Yi calculated the campaign would require a year: “100 days to march, 100 days to fight, 100 days to return, with 60 days for rest.” His strategic foresight extended to naval defenses against potential Wu reinforcements—a threat that never materialized due to Sima’s preemptive diplomacy with the Wa Kingdom (Japan).

The campaign unfolded with textbook brilliance. Ignoring Gongsun’s fortified trenches at Liaosui, Sima Yi bypassed defenses to strike directly at the undefended capital Xiangping. When monsoon rains swelled the Liao River to near-flood levels for over a month, his refusal to retreat—”Rain cannot last forever”—proved decisive. By August, after a grueling siege marked by cannibalism among the starving defenders, Xiangping fell. Gongsun Yuan and his son were executed fleeing southeast, their heads displayed at Liangshui River.

The Art of Ruthless Statecraft: Massacres and Monuments

Sima Yi’s postwar actions revealed his mastery of psychological governance. The slaughter of 7,000 officials and civilians to create a “Jingguan” (monumental pile of corpses) served as a brutal warning against rebellion. Yet simultaneously, he honored Gongsun Yuan’s virtuous opponents like Lun Zhi and Jia Fan with proper burials and family pensions—a calculated display of “rewards and punishments.” This dual approach cemented Wei’s control over four commanderies extending into the Korean Peninsula.

The Emperor’s Deathbed and a Power Vacuum

As Sima Yi returned victorious, urgent news arrived: Emperor Ming was dying without heirs. The 35-year-old ruler had adopted two young princes (7-year-old Cao Fang and his brother), setting the stage for a regency crisis. Initially, Emperor Ming appointed his uncle Cao Yu—married to a Daoist leader’s daughter—as Grand General, hoping to leverage religious networks. But palace intrigue intervened when senior secretaries Liu Fang and Sun Zi, fearing purge by the new regime, manipulated the dying emperor into replacing Cao Yu with the mediocre Cao Shuang—with Sima Yi as his “advisor.”

The Race to Luoyang: Sima Yi’s Calculated Gambit

Receiving contradictory orders—first to bypass Luoyang for Chang’an, then an urgent recall—Sima Yi recognized the capital’s power struggle. His decision to rush back proved pivotal. The secretaries’ coup had already unfolded: Liu Fang physically guided the emperor’s hand to sign edicts demoting Cao Yu and elevating Cao Shuang. By the time Sima Yi arrived, the political landscape had shifted irrevocably.

Legacy of the 238 Turning Point

This episode marked several critical developments:
1. Military Prestige: The Liaodong campaign established Sima Yi as Wei’s indispensable commander.
2. Political Theater: His simultaneous brutality and benevolence in postwar governance became a model for later warlords.
3. Regency Dynamics: The manipulated succession created the Cao Shuang-Sima Yi rivalry that would eventually topple the Wei dynasty.
4. Geopolitical Reach: Wei’s influence now stretched to the Korean Peninsula and Japan, where Queen Himiko’s envoys began formal relations.

Historically, 238 AD represents the moment Sima Yi—still ostensibly loyal—began his transformation from servant of the state to architect of its eventual usurpation. His handling of the Liaodong crisis demonstrated how military success, coupled with mastery of bureaucratic intrigue, could reshape an empire’s destiny. The stage was set for the rise of the Jin Dynasty, though that outcome still lay decades in the future.