A print showing the Mongol emperor Genghis Kahn (c.1162-1227). After uniting all the Mongol tribes under his leadership, Genghis Kahn conquered the whole of northern China, ruled by the Jin dynasty, including the siege and conquest of the vast capital city at Zhongdu.

There are few military leaders in world history with a more elevated reputation than the Mongol tribesman Temüjin, better known to history as Genghis Khan, or Chingghis Khan. Conqueror of half of Asia, his name became a byword for military ruthlessness and competence. No ambition was more vaunted or, in the end, more successful than his conquest of the vast northern Chinese Empire of the Jurchen Jin in the first decades of the thirteenth century. Few battles are more symbolic of the shift in the Asian power balance than the fight in 1214-15 to capture the Jin capital of Zhongdu on a site near present-day Beijing.
Temüjin left few records and many of those who knew him well were illiterate. He was an outcast from his Mongol tribe following the death of his high-ranking father, and was said to have learned how to judge others and exploit their differences from his mother, Hoelun. He overcame the disadvantages of his youth and became a successful Mongol prince and warlord, his exploits and his political cunning attracting Mongol warriors to his side. Since the tribal rivalries of the Mongolian plain were a constant source of jealous friction and political uncertainty, there seems little doubt that Temüjin’s own astuteness, ruthlessness and shrewd judgement, as much as his success in almost constant fighting, explain his emergence as the dominant figure over the Mongol peoples. By 1206, he had become at last Genghis Khan, ruler of the Mongols, the name by which he is commonly remembered.


In 1211, he embarked on the conquest of northern China, then ruled by the Jurchen Jin dynasty, which had captured the region from the Song some years before. His army probably totalled about 120,000, though the exact figures are not known. Mongol society was organized for military operations, since all men between the ages of fourteen and sixty were liable to serve when required. They learned to ride and to fire the powerful composite bows of the steppe horsemen from an early age; large hunting trips were used as surrogates for military training. Genghis Khan insisted on tough discipline, executing anyone who abandoned the fight or began to plunder before the order was given. The Mongol army was organized into units based on a decimal system: 10,000 men made a division, or tümen; each division was divided into units of 1,000, those into hundreds and the core unit was one of ten men. They were adept at ambushes and feints, and retained exceptional mobility.

The standard Mongol military practices, however, could not easily be deployed against large cities unless the garrison was foolish enough to sally out to fight. The conquest of Jin China required siege equipment, so Genghis recruited Chinese experts to supplement his large cavalry army. Much of the frontier area was conquered in rapid and devastating raids, but Genghis knew it was necessary to seize the Jin capital at Zhongdu to complete the conquest. The vast capital, surrounded by 15 kilometres (10 miles) of walls, 12 metres (40 feet) high, protected by 900 towers and a triple moat, was larger than any city the Mongols had captured. It was defended by an estimated 36,000 men, including 20,000 inside the walls and 4,000 stationed in each of four subsidiary towns where stores were kept, connected to Zhongdu by underground tunnels. Genghis and his army arrived outside the walls early in 1214. Two attempts to storm the city were beaten off. On the first occasion, it seems likely that the Chinese let some of the attackers break through a gate, only to set fire to the street behind them, trapping the Mongols and slaughtering them. Genghis knew when to stop. A truce was called and the Chinese emperor paid over a Jin princess, 500 boys and girls, 3,000 horses and 10,000 liang of gold to get the Mongols to leave.

Genghis almost certainly planned to return and when he heard in July that the emperor Xuanzong had decided to abandon Zhongdu as his capital and move it further south to Kaifeng, he took this as a sign of treachery and sent a large army of Mongols, Khitans and renegade Chinese to blockade the city. Blockade was not a usual Mongol strategy, but in this case it did what Genghis wanted. Xuanzong sent two large relief armies with supplies to break the blockade, but the first was surprised by a Mongol raid and its leader, the drunken Li Ying, was captured along with 1,000 wagons. The second suffered the same fate, ambushed at the River Yongding and destroyed by a much smaller Mongol force. The situation in Zhongdu became critical. One story has it that due to the shortage of stone or metal shot for the cannon in the city, among the first recorded uses of artillery with gunpowder if true, the ammunition was substituted with balls made of melted-down gold and silver. Genghis waited for the defenders and the population to starve. Cannibalism was later reported among both the besieged and the besiegers. The whole Mongol army now invested the city, preventing further supplies for the stricken capital. In late spring, the Jin commanders abandoned the city, Wanyen Fuxing choosing to commit suicide, while the army commander Mojan Chinchung smuggled himself at night through the Mongol lines, only later to be executed by the emperor in Kaifeng.

In June, the abandoned garrison opened the gates and surrendered. Although Genghis had wanted to prevent the usual bloodbath, his angry and impatient soldiers looted the city (this was their only source of payment for military duty) and butchered thousands of the inhabitants, though not as mercilessly as in later sieges – at Urgench in 1220, the entire population would be decapitated and pyramids built of their heads. The capital, with its vast walls, was now a Mongol city, signalling the rapid decline of Jin rule. By 1234, the rest of Jin China was subject to the Mongols. Genghis Khan proved himself a shrewd commander, whether fighting on an open plain or besieging vast cities. According to his published Bilik (Maxims), he saw warfare as the finest of activities: A man’s greatest pleasure is to defeat his enemies, to drive them before him, to take from them that which they possessed.’ Warfare was the breath of life for Genghis Khan, a fact that helps to explain his remorseless pursuit of battle and the single-minded quality of his leadership.