224 AD

AD 224 is the year of Cao Pi’s large-scale invasion of Wu, an expedition defeated by deception, defensive preparation, and attacks on its retreat. Its account contrasts the impressive scale of Wei’s forces with the limits of sheer numbers when the enemy controls the river defenses and the route of withdrawal.

Invasion preparations

After the alliance between Shu and Wu was renewed, Cao Pi ordered preparations for an immediate invasion, despite advice that Wei should wait and build up its military resources. By autumn AD 224, the preparations were complete: ten dragon boats, each more than two hundred feet long and able to carry two thousand men, joined a fleet of three thousand warships. The combined land and naval forces numbered more than three hundred thousand.

The scale of the mobilization made the Great River the decisive defensive line. With Lu Xun defending Jingzhou, Sun Quan appointed Xu Sheng to organize the defense there. Xu Sheng’s task was not simply to oppose the fleet directly, but to prevent its size from translating into a successful crossing and advance.

Xu Sheng’s defense

Xu Sheng’s preparations turned the apparent weakness of Wu’s position into a trap. During a heavy fog, Cao Pi’s forces saw no lights on the south bank and took this as evidence that the defenders had fled. When the fog cleared the next morning, they saw what seemed to be a vast wall, extending for roughly a hundred miles and guarded by a large army. The wall had been constructed overnight on Xu Sheng’s orders, but its deceptive appearance was enough to persuade Cao Pi that an attack would be futile.

Cao Pi concluded that his army could not overcome the apparent numbers and skill of the defenders. The weather further threatened the invasion: rising winds put the imperial dragon boat at risk, and Wen Ping intervened to rescue Cao Pi. Xu Sheng’s false fortifications had already checked the advance; the worsening conditions increased the danger of remaining on the river.

Retreat and defeat

News then arrived that Zhao Zilong and his men had advanced from Yangping Pass toward Chang’an. Facing this threat to Wei’s capital, Cao Pi ordered a retreat along the river. Sun Shao attacked the withdrawing forces and nearly captured the Wei ruler; the retreat also cost Cao Pi half his men.

The danger continued when Cao Pi tried to leave the water for dry land. Burning reeds soaked in oil blocked his route, and Ding Feng attacked. Zhang Liao was badly wounded, while Xu Huang helped Cao Pi escape. The invasion ended in a severe defeat for Wei: many soldiers died, Wu captured an immense quantity of spoils, and Zhang Liao later died of his wounds. Cao Pi gave him a full military funeral.

Significance

The episode makes the invasion’s great numbers a measure of its vulnerability rather than a guarantee of victory. Xu Sheng’s overnight imitation of a formidable defensive line halts the advance without requiring Wu to meet the invaders in a straightforward contest of strength. Once Cao Pi withdraws, the river route becomes a succession of dangers, and the expedition’s retreat compounds the failure of its initial objective.

The year’s campaign also connects military events on separate fronts. As Cao Pi retreats, Zhao Zilong is recalled from his planned advance toward Chang’an because Yong Kai’s rebels, supported by Meng Huo, have attacked southern areas of Shu with more than a hundred thousand men. Kong Ming decides to address that threat himself and needs Zhao Zilong back in Chengdu to guard the capital. Thus the episode’s conclusion redirects attention from Wei’s failed invasion to the pressure on Shu’s southern territories.