Siege of Kaifeng (1232)

From April 1232 to May 1233, Mongol forces under the general Subutai besieged Kaifeng, capital of the Jin dynasty, which the Jurchen people had established across northern China. Famine, plague and the flight of the Jin emperor broke the defence, and the city opened its gates on 29 May 1233. The siege is also one of the best-recorded early uses of gunpowder weapons in war, and it brought the end of the Jin dynasty within a year.

In the early thirteenth century China was split between three states: the Jurchen Jin in the north, the Tangut-ruled Western Xia in the west and the Song dynasty in the south. After Genghis Khan united the steppe peoples in 1206, the Mongols invaded Jin territory in 1211. They besieged the Jin capital Zhongdu in 1213, and the Jin court moved south to Kaifeng in 1214. Zhongdu fell in 1215, and by 1216 large parts of the Jin realm were in Mongol hands. Revolts by Khitans in Manchuria and by the "Red Coat" rebels in Shandong weakened the Jin further. Genghis died in 1227, and his successor Ögedei renewed the war in 1230.

Ögedei and his brother Tolui led two armies towards Kaifeng from the north and south, but both fell ill and left the campaign. Tolui died the following year. Subutai took command of the combined force, which reached the Yellow River in late January 1232 and laid siege to Kaifeng on 8 April. Jin forces are said to have been far larger, but the Mongol army, perhaps 15,000 men under Subutai, held the city in a tight grip.

Peace talks made some progress in the summer of 1232 until the Jin side killed the Mongol envoy Tang Qing and his party. Inside the walls, plague spread, food ran short and supplies were seized from residents. Fear of treachery led to the execution of suspected traitors.

A detailed account by a Jin official inside the city describes the weapons used. The defenders hurled bombs from trebuchets that exploded on landing, pierced armour and set fire to the grass. When the Mongols dug trenches covered with cowhide shields up to the walls, the Jin lowered bombs on iron chains into them. Jin infantry also carried fire lances, spears fitted with a tube of gunpowder mixed with iron filings and ground porcelain, which shot flame about three metres. Historians disagree about whether the Mongols used gunpowder themselves at Kaifeng.

The city held out for months. Late in 1232 Emperor Aizong slipped out with his court, reaching Guide in February 1233 and later Caizhou, and left General Cui Li in charge. The emperor's departure shattered morale. Cui executed loyalists who had stayed behind, judged further resistance hopeless and surrendered. The Mongols entered Kaifeng on 29 May 1233 and plundered it, though they allowed trade, and wealthy residents swapped valuables for food. Male members of the Jin imperial family were put to death and the palace women carried off to the north.

Aizong asked the Song for help, warning that the Mongols would turn on them next, but the Song, long hostile to the Jurchens, allied with the Mongols instead. The combined forces besieged Caizhou from December 1233. Aizong took his own life, and the town fell on 9 February 1234; his chosen successor, Emperor Mo, was killed the next day, and the Jin dynasty ended. Aizong's warning came true a year later, when the Mongol conquest of the Song dynasty began.

Our 1200 map shows the Jin realm in northern China between the Song and the Mongol Empire as it was about to rise, and our 1279 map shows the whole country under the Mongol Yuan dynasty.