The Battle of Baimá turns on a disparity of forces and a single commander’s decisive intervention: against Yuan Shao’s far larger army, Cao Cao summons Guan Yu, whose killing of Yan Liang breaks the opposing force’s composure and enables Cao Cao’s army to rout it. The victory brings a political reversal as well as a battlefield success: Yuan Shao interprets Guan Yu’s action as evidence that Xuande has plotted against him and orders Xuande seized for execution.

Background and stakes

When spring comes, Cao Cao and Yuan Shao agree to go to war and choose Baimá as their primary target, despite warnings from some of their advisers that an attack on the capital would end in disaster. Cao Cao sets out with 150,000 men. Yuan Shao’s army is described as immense, while the later account of the wider campaign at Guandu emphasizes that Cao Cao could muster only about a tenth of Yuan Shao’s numbers and had limited supplies. The contest therefore carries a clear military risk for Cao Cao: delay could make his smaller force’s position worse.

At Baimá, Yan Liang commands Yuan Shao’s troops. Cao Cao first sends Song Xian, a former associate of Lü Bu, to challenge him; Yan Liang kills Song Xian with one stroke. Wei Xu then asks to avenge his friend, but is also quickly defeated. Xu Huang manages to fight Yan Liang for twenty rounds before withdrawing. These failed challenges leave Cao Cao’s commanders deeply troubled and establish Yan Liang as the immediate obstacle to the army’s advance.

Guan Yu’s intervention

Cao Cao concludes that Guan Yu is the one warrior capable of defeating Yan Liang. Cheng Yu sees a political opportunity in the assignment: if Guan Yu kills Yuan Shao’s commander while Xuande is with Yuan Shao, Cheng Yu reasons, Yuan Shao will turn against Xuande, and Guan Yu may then have no choice but to remain in Cao Cao’s service. The command thus serves both a military need and a calculated attempt to alter Guan Yu’s loyalties.

Summoned by Cao Cao, Guan Yu rides Red Hare and carries the Green Dragon. Cao Cao takes him to a hilltop and points out Yan Liang. Guan Yu immediately rides down toward the enemy. The opposing ranks part as he advances, and Yan Liang, caught unprepared, is killed by Guan Yu’s thrust. Guan Yu takes the commander’s head and returns to Cao Cao. The account presents the act not as a prolonged duel but as a sudden, concentrated strike that overturns the expectation created by Yan Liang’s earlier victories.

Rout and political consequences

Cao Cao’s army attacks when it sees the enemy paralyzed by terror and astonishment. The northern force is routed; many are killed, and the victors seize a large amount of loot. Guan Yu presents Yan Liang’s head to Cao Cao, who marvels at the feat. Guan Yu answers by praising Zhang Fei as an even more formidable warrior, prompting Cao Cao to warn his commanders to remember the claim.

The victory produces the political consequence Cheng Yu anticipated. When Yuan Shao hears that Guan Yu has defeated his commander, he assumes Xuande must have plotted the outcome and orders him seized for execution. Xuande, who is already distressed about his brothers’ capture by Cao Cao and anxious about his family, is now threatened by the very victory that demonstrates Guan Yu’s continuing attachment to him. The battle therefore sharpens the separation between the brothers while making Guan Yu’s service to Cao Cao more precarious: his battlefield usefulness does not erase his allegiance to Xuande.

Narrative function

The encounter is part of the novel’s transformation of historical conflict into an epic of recognizable characters, reversals, and exemplary deeds. The book’s introduction describes historical records as the underlying framework, supplemented by folk storytelling and theatre and then shaped by a novelist. In that structure, Baimá’s military outcome also becomes a test of loyalty and political interpretation: Cao Cao exploits Guan Yu’s prowess, Cheng Yu tries to turn the result into a break between Guan Yu and Xuande, and Yuan Shao reads the same result as proof of Xuande’s treachery.

The scene’s concentrated action contrasts with the wider campaign’s concern about numbers and supplies. A single warrior’s success decides the immediate engagement, but it does not settle the larger contest or secure Xuande’s safety. Instead, it carries the consequences of the battlefield into the political sphere, leaving victory and danger joined in the same moment.