Background
The establishment of the heir apparent in the twenty-second year of Jian'an (217) took place at the critical juncture when the Caowei regime had completed its formal transition from "hegemon's court" to "royal state." From the eighteenth year of Jian'an onward, Cao Cao had accepted investiture as Duke of Wei and established the altars of soil and grain; by the twenty-first year he had been elevated to King of Wei; by the twenty-second year Wei already possessed the full structure of a proto-dynastic state — ancestral temples, official hierarchy, ritual — but lacked only a legitimate heir. Whom to designate meant determining whether this semi-independent polity could make a smooth transition after Cao Cao; it was also directly tied to the ongoing pressure against Emperor Xian of Han — only with the position of heir firmly settled did usurpation have a roadmap.
Key Figures
Cao Pi was five years older than Cao Zhi, had followed his father on campaigns since youth, and had a steady character — yet lacked the dazzling literary brilliance that Cao Zhi possessed. Cao Zhi was the archetype of "talent surpassing all," favored by Cao Cao for many years, and surrounded on all sides by the "Zhi faction" of Yang Xiu, Ding Yi, and Ding Yi rallying support for him. Around Cao Pi stood Wu Zhi, Sima Yi, Chen Qun, Jia Xu, and others — largely mature counselors of the statecraft type. Cao Cao himself wavered for extended periods between his two sons and was the most critical unpredictable variable in the contest for succession. The birth mother Bian Shi had come from a performer's family and had long maintained a low profile because of old grievances with the first consort; her stance on the succession tended toward quiet observation rather than active involvement.
Core Issue
The substance of the succession contest was the question of whether to allow a political newcomer who had triumphed on the basis of "talent" to take charge of a vast military-political complex still in a state of wartime mobilization. Those who supported Cao Pi emphasized the principle of legitimate primogeniture, military and administrative seasoning, and the breadth of court support; those who supported Cao Zhi placed their hopes on his cultural symbolic value and Cao Cao's personal preference. Cao Cao's true resolution of the matter is attributed in the Biographies of Jia Xu in the San Guozhi to an oblique piece of advice from Jia Xu — two cautionary precedents: Yuan Shao's deposing of the elder in favor of the younger led to fratricidal warfare between Yuan Tan and Yuan Shang and ultimately Wei's annihilation of both; Liu Biao's deposing of the elder in favor of the younger led to Jingzhou's effortless submission. These two negative examples covertly warned Cao Cao not to repeat the same mistake. This persuasion by "taking history as a mirror" is itself an expression of the political wisdom most prized by the men of letters of late Han.
Political Consequences
Once the heir apparent position was confirmed, political resources within the court rapidly concentrated around Cao Pi: the Eastern Palace's staff rose in status; Yang Xiu and others who had attached themselves to Cao Zhi were either suppressed or distanced, and Yang Xiu was ultimately put to death two years later on charges of "repeatedly leaking edicts and instructions and associating with the feudal lords" — generally regarded as an extended act of clearing out the Zhi faction to ensure a smooth transition to the heir apparent's position. Cao Pi also used this formal legitimation to more systematically build his own political base; the key roles that Wu Zhi, Chen Qun, and Sima Yi went on to play in early Wei politics can all be traced back to this year. Externally, the confirmation of the heir apparent meant the internal timetable for Wei to replace Han was formally set in motion — three years later (220), Cao Cao died, and Cao Pi completed the abdication transfer within months.
Counterfactual Analysis
If Cao Zhi had been installed instead, the most immediate risk was the loss of wholehearted loyalty from the pragmatic faction — Wu Zhi, Sima Yi, and Chen Qun. Cao Zhi's temperament was dissolute and undisciplined, incapable of strictly observing military orders (the episode in the twenty-fourth year of Jian'an when Cao Ren was besieged at Fancheng and Cao Zhi was too drunk to take up his appointment was seen as the moment Cao Cao finally despaired of him); after ascending the throne, he would very likely have lost control across multiple simultaneous fronts in Jingzhou, Guanzhong, and Huainan, handing the Sun-Liu alliance a window for counterattack. Another counterfactual: if Cao Cao had simply left the question unresolved and let it be settled after his death — given the record of chaos in succession among late Han warlords (both Yuan Shao and Liu Biao ended in such disorder) — this path would almost certainly have plunged Wei into fragmentation, and the window for Caowei to supplant Han would accordingly have closed. This establishment of the heir apparent, which appeared to be only a domestic family matter, in reality locked in the basic political trajectory of the northern part of China for the next sixty years.