Battle of Yamen

19 March 1279: the assault on the floating court

At Yamen, near present-day Jiangmen in Guangdong, Yuan forces under Zhang Hongfan and Li Heng made their decisive assault on 19 March 1279 — the chronicles' cyclical day guiwei, which a few modern compilations convert instead to 20 March. Li Heng attacked from the north, Zhang Hongfan pressed from the south, and after fighting from morning into the afternoon the Song formation broke.

The defenders were already failing before the first attack. The Yuan had occupied the harbor approaches and cut the fleet's access to wood and fresh water; after more than ten days on dry food, Song defenders drank seawater and suffered vomiting and diarrhea.

A chancellor, a child, and the sea

Song commander Zhang Shijie had connected more than 1,000 vessels — a mixed concentration of court, transport and military craft, not 1,000 warships — into a floating defensive complex. As the Yuan closed on the imperial center, he cut loose and escaped through the harbor with more than ten ships.

Chancellor Lu Xiufu, judging the emperor's large, encircled vessel unable to escape, carried the child emperor Zhao Bing into the water; both died. The Song-history account adds a grim coda to Zhang Shijie's escape: a small craft sent back to fetch the emperor was refused, because Lu Xiufu feared it might deliver the boy into Yuan hands.

By the end of the day, senior Song commanders had surrendered, the imperial seal and members of the court were captured, and more than 800 surviving vessels were in Yuan hands. Chronicles claim more than 100,000 died with the court — a medieval aggregate, not an auditable count.

What the victory was — and wasn't

This was not, despite the popular framing, a Mongol fleet crushing a Chinese one: modern scholarship emphasizes that both fleets were predominantly Han Chinese, with only a few thousand Mongols among the Yuan personnel. Zhang Hongfan himself was a Han Chinese general in Yuan service.

Nor did the battle make Kublai Khan emperor — he had proclaimed the Yuan dynasty in 1271. What ended at Yamen was the Southern Song's last organized dynastic government, a mobile loyalist court that had survived aboard ships under successive child emperors since losing its capital in 1276.