Background
The Romance of the Three Kingdoms places this episode during Cao Cao's southward campaign against Zhang Xiu in the second year of Jian'an, though its narrative function extends far beyond the campaign itself. A common dilemma facing all warlords of the late Han was how to prevent soldiers from plundering farming communities during large-scale troop movements. Marching at wheat harvest time was catastrophic for the people along the route — farmers would flee rather than dare to harvest, and once the wheat fields were trampled, the year's food supply was gone. Cao Cao had just completed the political arrangement of "holding the Son of Heaven in order to command the disobedient," and was at a critical juncture in building his image as a "Han Chancellor." He needed to demonstrate that he was different from old warlords like Dong Zhuo and Li Jue who let their armies plunder the population, and to lay the groundwork of popular trust for expanding the military-agricultural colony system. Issuing the order that anyone who trampled wheat would be executed was a piece of political advertising directed at the common people and officials alike; "the people, hearing the proclamation, were without exception delighted and full of praise" was the effect he intended to achieve.
Course of Events
According to the Romance's account, Cao Cao himself was riding along the edge of the wheat fields when his horse, startled by a frightened dove, bolted into the wheat and trampled a large patch. He immediately summoned the campaign's chief secretary to assess his crime — a scene performed almost like a stage production. The chief secretary, following bureaucratic convention, cited the standard principle that "the Chancellor cannot be charged with a crime," but Cao Cao insisted on following the procedure to its end, drawing his sword and feigning an attempt at self-inflicted death. Everyone present understood this gesture as theater — no general would actually allow the commanding officer to commit suicide in the middle of a campaign. But the performance itself was the point: it forced everyone present to bear the responsibility of "how to help the commander save face." Guo Jia intervened at the right moment, citing the classical principle from the Spring and Autumn Annals that "the law does not apply to the exalted" — a pretext that appeared classical in form but actually served modern governance. Cao Cao "deliberated for a long time" before pronouncing judgment, and finally cut off a lock of his own hair with his sword and threw it to the ground, declaring that "cutting my hair stands in for cutting my head." This entire sequence of gestures — threatening, deferring, reasoning, self-punishing, and making a public display — was tightly paced and resembled a carefully rehearsed political ritual.
Outcome
The immediate result of the hair-cutting was to elevate the enforcement authority of the military order — "any who pass through the wheat fields and trample them shall be executed" — to a level that no ordinary soldier could circumvent. Once the commander's own hair had been cut off and displayed before the three armies, any soldier who dared to trample wheat, regardless of what defense he might offer, could only be severely punished — for there was no identity higher than the Chancellor's that he could invoke. "The three armies were struck with awe, none daring not to comply with military orders" captures the immediate psychological effect of this ritual. Within the ritual context of Han propriety, having one's hair shorn (the kun punishment) was itself a formal penalty. Hair given by one's parents could not be lightly damaged; using hair in place of one's head was not the Romance's fictional exaggeration — at the symbolic level it genuinely approximated a self-inflicted punishment, and therefore carried real deterrent force.
Impact
This episode later became one of the classic cases in Chinese political tradition of "punishing the high ministers" and "the ruler punishing himself," cited by countless later emperors and officials as a rhetorical template for imposing military discipline and rectifying governance. In terms of characterization within the Romance, it precisely captures the core contradiction of Cao Cao's dual identity as "bold chieftain and master of political calculation": on the surface self-punishing to demonstrate impartiality, but in reality using a single dramatic act of exemption from punishment to institutionalize the special privilege that "the Chancellor cannot be charged" and proclaim that privilege to the entire army. Compared with the frank villainy of "I would rather wrong others than have them wrong me," the hair-cutting in lieu of decapitation represents a higher order of political wisdom — it compresses the violation of the law, self-reproach, the granting of clemency, and the demonstration of authority into a single dramatic gesture. Viewed through the lens of modern political communication, this was the earliest and most sophisticated instance of "political performance art" among the warlords of the late Han — establishing the narrative archetype of Cao Cao as "a ruler who knew how to perform for his people and soldiers," transmitted down to the present day through the text of the Romance.