Key point: The Mongols learned from any defeat, adjusting their strategy. Here's how they managed to smash their way into China.
In ad 1205, Mongol ruler Genghis Khan, having completed the unification of his Gobi Desert empire, began looking south toward China for further conquest. The ever-truculent Mongols had been a thorn in China’s side for more than 2,000 years. Their many raids were the main reason the Chinese had constructed a 1,500-mile-long Great Wall from the eastern coast on the Pacific Ocean to the very edge of the Gobi. Not without reason did the Chinese consider the Mongols barbarians—their very name meant “earth shakers.” At the head of a united army of fearsome nomads, Genghis Khan would soon make the earth shake again.
War With Xi Xia
Genghis’s first target was the western Chinese kingdom of Xi Xia. The Xi, known to the Mongols as the Tanguts, had emigrated east from the mountains of Tibet to the hilly grasslands centered on the Yellow River in the 7th century ad. The Mongols and the Xi, as wary neighbors, shared some of the same relatives; one of Genghis’s own stepdaughters was the wife of a Tangut chieftain. Family ties meant little to Genghis Khan. His father, Yesugei, had been poisoned by grudge-bearing members of a Tatar clan when Genghis, then called Temujin, was eight. Five years later, Temujin killed his own half brother Begter in cold blood after the two quarreled over some birds and minnows that Temujin had caught. “Apart from our shadows we have no friends,” he had been taught from the cradle. It was lesson he never forgot. After he had consolidated his power, Genghis Khan killed every male member of the Tatar clan that had killed his father—any boy taller than a wagon wheel was struck down.
The Mongols attacked the Xi Xia in 1209, first taking the border settlements north of the Yellow River. The 75,000 Mongol invaders faced an army of 150,000 Xi Xia troops near their capital at Zhongxing. The Xi Xia had stationed 100,000 armored pikemen and crossbowmen in large phalanxes in the center of the battle line, with 25,000 Tangut cavalry on each wing. The Mongols were not accustomed to being outnumbered. As nomadic warriors they traveled fast, in huge columns of superbly skilled cavalry, often separated by many miles but knit together by an intricate system of signal fires, smoke signals, and flags, and a gigantic camel-mounted kettledrum to sound the charge. They were used to coordinating their forces on small settlements or camps whose residents could not move with anything like the same speed or decisiveness. The Mongols were interested not in a fair fight, but a victorious one.
In the Xi Xia, however, they ran into an opponent who fought much the same way they did. The Mongols had taken extensive casualties in an earlier battle with the Xi Xia pikemen by charging their pike wall; they were determined to not repeat the mistake. The Mongol light cavalry rode parallel to the Chinese pikemen and crossbowmen, firing thousands of arrows into them while other Mongol forces fought with Tangut cavalry on the flanks. The Mongol and Tangut cavalry also rode parallel to each other, firing thousands of arrows and inflicting innumerable casualties on each side. Each side’s cavalry feigned retreat, but the other side wouldn’t fall for the ruse. Finally, the Mongols attacked the Tangut cavalry with their heavy cavalry. The Tangut cavalry broke and ran, leaving the huge phalanxes of the Xi Xia pikemen vulnerable to attack. The Chinese pikemen had formed a giant rectangle that faced in all directions, and they took repeated volleys of arrows that inflicted great damage while the Mongols themselves stayed mostly out of range of the Chinese crossbows. After the Xi Xia pikemen lost unit cohesion, the Mongol heavy cavalry attacked the remaining demoralized and exhausted Chinese from all sides to finish them off.
The Xi Xia capital of Zhongxing presented a new problem for the Mongols, who had little experience in siege warfare. In an earlier siege of the walled city of Volohai, the Mongols had attempted a series of suicidal assaults with scaling ladders that failed, and they suffered heavy casualties in the fighting. Genghis offered to lift the siege of the city provided the residents gave the Mongols 1,000 cats and 10,000 swallows in cages. The puzzled citizens of Volohai quickly granted the request—and just as quickly lived to regret it when the animals fled back into the city with tufts of flaming wool tied to each of them by the Mongols. Soon, the whole city was ablaze. While the defenders were occupied with putting out the fire, the Mongols scaled the now undefended walls and massacred the inhabitants.
Genghis did not want to face a similar costly assault of the walls of Zhongxing. Instead, he decided to break the dikes on the Huang River and flood the city below. The plan backfired, however, when the Mongol camp itself was flooded and hundreds of troops were swept away by the raging waters. To make matters worse, the move left two feet of standing water for miles around the city, in effect creating a ready-made moat. The Mongols retreated into the surrounding hills but returned in force in 1210. Xi Xia Emperor Li Anquan, not wishing to face another siege, agreed to give his daughter Chaka to Genghis Khan as a wife and to pay tribute to the Mongols as a vassal state. Genghis demanded and received another 1,000 young men and women, 3,000 horses, and vast quantities of gold, jewelry, and silk. The Xi Xia later rebelled in 1218 and 1223 because they tired of providing the Mongols with so many men to fight in their wars of conquest, but these rebellions were brutally put down.
Routing the Jin
In 1210, an emissary of the newly installed Jin emperor, Prince Wei, appeared before Genghis and demanded his submission and a tribute paid to the Jin. An infuriated Genghis answered that it was the Jin who needed to pay tribute to him; he spat on the ground as a gesture of defiance. With his flank secured by the conquest of Xi Xia, Genghis was ready to attack the mighty Jin Dynasty. In 1211, 30,000 Mongol troops under Genghis’s greatest general, Subedei, assaulted the Great Wall. The Mongols brought up groups of archers who cleared an area of wall while other Mongols scaled the wall with ladders and took possession of sections of it. The Jin rushed in reinforcements and recaptured the lost sections of the Great Wall. Thousands died on both sides as the fighting continued back and forth for several days.
The Jin brought most of their army to back up the forces defending the Great Wall. What the Jin didn’t know was that Subedei’s attack was merely a diversion. Some 200 miles to the west, Genghis and a force of 90,000 Mongols were crossing the Great Wall at its end in the Gobi Desert. The Onguts, a tribe similar to the Mongols, were supposed to be guarding the western end of the Great Wall for the Chin, but they defected to Genghis and allowed the Mongols to cross into China unmolested. After Genghis’s cavalry poured into China, Subedei’s force broke off its attack and crossed over into China from the end of the Great Wall as well.
The Jin forces were now out of position and moved to cut off the Mongols from Beijing. Genghis’s cavalry caught close to 200,000 Jin troops on open ground near Badger Pass, where the Jin hoped to block the Mongols from advancing any farther. The Jin formed for battle with the pike phalanxes and crossbowmen in the middle and armored heavy cavalry on the flanks. The outnumbered Mongol heavy cavalry engaged in a hotly contested battle on the flanks with the Jin cavalry as the densely packed Jin phalanxes and their crossbowmen held off the Mongol horse archers. Suddenly, Subedei’s remaining 27,000 Mongols (3,000 had died at the Great Wall) showed up on the battlefield on the flanks and rear of the Jin army. The rout was on.
After the Jin cavalry was defeated, the Jin pikemen, half of whom were militia conscripts, broke and ran. They were cut down by the Mongol cavalry or trampled by their own terrified horsemen. Bodies stacked “like rotten logs” littered the ground for more than 30 miles. Genghis then separated his army into three forces that burned, pillaged, raped, and murdered the populations of 90 cities over the next six months. Despite the awful destruction, the Jin would not surrender. Genghis became frustrated by the enormous size and scope of a nation-state like the Jin. He entered into negotiations with the emperor and agreed not to attack any more cities. The Mongols had already captured well over 100,000 Chinese prisoners; to make a negotiating point, Genghis had them executed.
The Capture of Beijing
The next year the Jin moved their capital farther south, from Beijing to Kaifeng, and began rebuilding their armies. Genghis was angered by the move, which he considered a betrayal of trust, and looked for an opportunity to attack the Jin again. In the spring of 1213, the Jin attacked the Mongol-allied Khitan tribe in Manchuria. Genghis came to the aid of his Khitan allies and attacked the Jin armies in Manchuria, which fell back to their fortifications at Nankuo Pass. The Mongols were blocked from attacking Beijing by the well-fortified Jin positions at the pass and by the eastern sections of the Great Wall. The Mongols headed into the pass and then retreated. It was all a ruse. The Jin forces hurried to trap the fleeing Mongols, recklessly leaving their fortified positions to pursue them. The Mongols led the Jin forces into their own trap and destroyed most of the Jin army. Those Jin troops that had not pursued the Mongols fled their fortified positions and retreated to the Great Wall, with the Mongols in hot pursuit. The Mongols caught and destroyed the remaining Jin troops as they tried frantically to retreat through the Great Wall. The Mongols then passed through the open gates of the Great Wall.