The Mongols Conquer the Great City of Kaifeng

The fall of the city of Kaifeng, the capital of the Jin State on the 26th of February, 1233 was the decisive moment in one of the greatest wars of the medieval period, the war between the Mongols and the Jin State that lasted from 1211 to 1234. It was also the culmination of the greatest power struggle between the various "peoples of the steppes" who dominated Chinese history for a thousand years - from the fall of the Tang Dynasty in 907 to the fall of the Manchu Dynasty in 1912).

The Jin State was founded by the Jurchens, a nomadic Manchurian people who were traditional enemies of the Mongols. After overthrowing the Liao State in the North of China in 1125, they turned on their former allies, the Chinese Song Empire, beginning a period of 100 years when the two states were often at war.

In 1127 the Jin captured the Song capital of Kaifeng, then the largest city in the world with a population of around 600,000, and pushed the Song State into Southern China, while they ruled Northern China from their capital at Zhongdu (later known as Beijing).

When Genghis Khan started to build up Mongol power, the Jin demanded his submission. But Genghis, remembering the injuries suffered in the past by the Mongols at the hands of the Jin and their allies, decided instead to go to war. The war started in 1211 and was the defining conflict of his career. 

Although the Mongols defeated the Jin in the open field, they were as yet unskilled in taking heavily fortified cities and were unable to capture Zhongdu. In 1214, the Jin Emperor Xuanzong made a temporary peace with the Mongols and moved his capital and court to Kaifeng. This was essentially a move that showed the weakness and lack of fighting spirit of the Jin. The next year the Mongols took Zhongdu with the help of several major defections of Jin troops. 

In 1224 the Emperor Xuanzong was succeeded by his able but ill-fated son Emperor Aizong. He made peace with the Southern Song State and sought an alliance with the Western Xia state in the West of China in order to resist the Mongols. As the Western Xia had already submitted to the Mongols, Genghis Khan reacted to this move by attacking and crushing Western Xia State in 1227. The next step was a renewed attack on the Jin State again, but fate intervened and Genghis Khan died, giving the Jin State a breathing space. 

The new Khan was Genghis's son Ogedai. After a transition period, the attack on the Jin State resumed in earnest in 1229. In early 1232 the main Jin army was crushed in the Battle of Three-Peaked Hill fought in snowy conditions, and by April two Mongol armies had advanced from the North and surrounded the capital of Kaifeng, beginning a ten month siege. Sabutai, one of the greatest Mongol generals, was in command.

The subsequent struggle was marked by dogged resistance from the Jin forces, who used various kinds of gunpowder weapons to resist the invaders, like "thunder-crash-bombs" and "fire lance flamethrowers." The former of these were hollowed-out stones loaded with gunpowder, hurled by trebuchets, that then exploded, often in mid air. The latter were an early form of gun attached to spears and used in close quarters fighting.

Ogedai Khan

While the fighting continued, the city suffered from plague and starvation. As long as the Emperor Aizong stayed with his troops, stout resistance continued, but towards the end of the year, he had an opportunity to escape and took it. He hoped to raise a new army and also persuade the Song to join forces, but they instead sided with the Mongols. 

After he left, the morale of the troops defending Kaifeng fell. This was a repeat of the pattern of Zhongdu, where the Jin troops also became demoralized when the Emperor retreated.

Finally General Cui Li, who had been left in command, seeing the situation was pointless, executed the remaining supporters of the emperor and surrendered the city to the Mongols.

The Jin State continued until the next year, when the Emperor Aizong was again besieged in another city and committed suicide by hanging himself. As soon as the Jin State was extinguished the Song State broke its alliance with the Mongols and recaptured Kaifeng and some other cities, starting the war that would lead to its destruction as well.