King Midang

King Midang is the ruler of the Qiang who joins Jiang Wei’s campaign against Wei in AD 253. His alliance brings additional forces to Shu’s side, but Wei commander Chen Tai infiltrates it under the pretense of desertion. Captured and then released by Guo Huai, King Midang abandons the alliance and attacks the Shu camp, helping turn the campaign into a defeat for Jiang Wei.

Alliance with Jiang Wei

In AD 253, Jiang Wei again leads Shu forces toward the Wei border and seeks the support of the Qiang through generous gifts. The inducements succeed: King Midang brings his army to join the invasion. His participation makes the campaign a coalition effort, connecting Shu’s military ambitions with a regional ruler and his forces.

That alliance is tested by the course of the fighting. The first engagement goes badly for Shu, with the Wei general Xu Zhi inflicting heavy losses. In the next engagement, however, Wei suffers a reversal: Xu Zhi is killed, the Shu army overwhelms the Wei camp, and Sima Zhao’s troops are driven to a hilltop where their limited spring cannot meet the needs of six thousand men. The changing fortunes of the battle form the setting for the deception that follows.

Capture and Defection

Wei commander Chen Tai pretends to desert with five thousand men and joins the Qiang-Shu alliance. His apparent defection is a stratagem: he intends to induce the Qiang to attack the Wei camp, where they can be ambushed. Trusting Chen Tai, King Midang orders a night assault. During the attack, a senior Qiang commander’s horse falls into a pit; the supposed deserters then turn on the Qiang from behind, while Chen Tai leads another Wei detachment against them from the front.

The ambush kills thousands of Qiang and captures King Midang. Guo Huai releases him, and King Midang then turns against his former allies: he attacks the Shu camp, taking its troops by surprise and overwhelming it. Jiang Wei is forced to flee, though he wounds Guo Huai in the retreat; Guo Huai dies that night. King Midang’s change of allegiance therefore helps end the immediate threat to Wei, even as the campaign leaves casualties on both sides.

Significance in the Campaign

After the armies withdraw, Jiang Wei’s expedition has failed, although the deaths of Xu Zhi and Guo Huai mean it has not yielded nothing for Shu. For Wei, the defeat of the attack strengthens Sima Shi’s control. King Midang’s role turns on the fragility of the alliance: gifts first bring him into the campaign, but Chen Tai’s false defection makes that trust exploitable, and Guo Huai’s release precedes his return to Wei’s side.

The episode presents King Midang chiefly through political and military allegiance rather than through a personal history. He appears as a ruler capable of mobilizing his army and directing an attack, but the narrative gives little account of his motives beyond the alliance and subsequent reversal. His capture and defection make him pivotal to the campaign’s outcome, while also showing how a coalition’s strength can become a vulnerability when its members are deceived.