The Battle of Mianzhu is the final major stand described here against Deng Ai’s advance into Shu: Zhuge Zhan and his son Zhuge Shang refuse to abandon the defense, but their attempt to break out ends in defeat and death. Mianzhu falls the following day, leaving the way to Chengdu open and turning a local battle into an immediate crisis for the Shu court.

The approach to Mianzhu

The battle follows Deng Ai’s unexpected advance through Jiangyou. At Chengdu, the ruler had been alarmed by reports of the Wei incursion, but Huang Hao had dismissed them as false. Once the danger could no longer be ignored, the officials called on Zhuge Zhan, Kong Ming’s son. Though he had earlier withdrawn from court life, pleading illness after despairing of its corruption, Zhuge Zhan now took command of the troops at Chengdu.

The earlier fighting initially favored Shu. When the Wei tried to break through, Zhuge Zhan appeared in Kong Ming’s famous carriage. The sight unnerved the Wei troops, who fled and suffered heavy losses as the Shu pursued them. Deng Ai then tried to win Zhuge Zhan over with a flattering letter. Zhuge Zhan rejected the overture, tore up the letter, and had its messenger executed. His refusal made clear that he would not change sides, even as the campaign turned against him.

Deng Ai’s reversal

Deng Ai eventually used a retreat-and-ambush strategy to inflict a crushing defeat on Shu. The Wei army pressed forward and besieged Mianzhu, making the city the focus of the defense. Zhuge Zhan appealed to Sun Xiu of Wu for reinforcements. Sun Xiu agreed to send troops, but they needed time to prepare; Zhuge Zhan had no assurance they would arrive before the city’s fate was decided.

With hope failing, Zhuge Zhan chose to attempt a breakout rather than wait behind the siege. His son Zhuge Shang rode out with him, alongside the army, to fight Deng Ai. The decision ended catastrophically: both father and son died in the fighting. Deng Ai, moved by their courage, gave them honorable burial after his victory. That gesture acknowledges the defenders’ valor without altering the military result.

Fall and consequence

Mianzhu fell the next day. Its capture cleared the way for the Wei army to march on Chengdu, and the narrative immediately raises the question of whether this marks the end of Shu. The battle is therefore both the conclusion of Zhuge Zhan and Zhuge Shang’s resistance and a turning point in the campaign: Shu’s capital is now directly threatened, while the promised Wu reinforcements have not yet arrived.

The episode places courage and strategic defeat side by side. Zhuge Zhan’s earlier successes and refusal of Deng Ai’s offer establish his loyalty, but neither resolve nor personal valor can reverse the effects of the Wei ambush and the fall of the city. Deng Ai’s decision to honor the dead makes the ending more than a simple account of victory: the defenders lose Mianzhu, yet their conduct is recognized even by the commander who defeats them.