Mongol-Jin Dynasty War
Wanyan Heda's Jin army still had more than 100,000 men after the battle at Mount Yu, and the Mongols adopted a strategy of exhausting the enemy.
The Jin troops had had little rest all the way from Dengzhou, and had not eaten for three days because of the severing of their supply lines. Their morale was plummeting and their commanders were losing confidence. When they reached Three-peaked Hill, a snowstorm suddenly broke out, and it was so cold that the faces of the Jin troops went as white as corpses, and they could hardly march. Rather than attack them when they were desperate with their backs to the wall, the Mongols left them an escape route and then ambushed them when they let down their guard during the retreat. The Jin army collapsed without a fight, and the Mongols pursued the fleeing Jin troops relentlessly. Wanyan Heda was killed, and most of his commanders also lost their lives. After the Battle of Three-peaked Hill, Kaifeng was doomed and the Jin emperor soon abandoned the city and entered Hebei in a vain attempt to reestablish himself there. Thousands of people--offered a stubborn resistance to the Mongols, who entrusted the conduct of the attack to Subotai, the most daring of all their commanders. The Jin Emperor was driven south again, and by this time Kaifeng had been taken by the Mongols so he established his new capital at Caizhou (Runan, in Henan). Subotai wished to massacre the whole of the population. But fortunately for the North Chinese, Yelu Chucai was more humane, and under his advice Ogodei rejected the cruel proposal.
The Song, wishing to give them the coup de grace, declared war upon the Jin, and placed a large army in the field under their best general, Mongkong. The remainder of the Jurchen army, under their sovereign Ninkiassu, took shelter in Caizhou, where they were closely besieged by the Mongols on one side and the Song on the other. Driven thus into a corner, the Jins fought with the courage of despair and long held out against the combined efforts of their enemies. At last Ninkiassu saw that the struggle could not be prolonged, and he prepared himself to end his life and career in a manner worthy of the race from which he sprang. When the enemy broke into the city, he heard the stormers at the gate of his palace. Wanyan Shouxu committed suicide, and the Jin dynasty was finally destroyed. He retired to an upper chamber and set fire to the building. Many of his generals, and even of his soldiers, followed his example, preferring to end their existence rather than to add to the triumph of their Mongol and Song opponents. Thus came to an end in 1234 the famous dynasty of the Jurchens. Ninkiassu, the last of their rulers, was not able to sustain the burden of their authority, but he at least showed himself equal to ending it in a worthy and appropriately dramatic manner.
Fall under the Mongol Empire
Starting from the early 13th century the Jin Dynasty began to feel the pressure of Mongols from the north. Genghis Khan first led the Mongols into Western Xia territory in 1205 and ravaged them four years later. In 1211 about 50,000 Mongols on horses invaded the Jin Empire and began absorbing Khitan and Jurchen rebels. The Jin army had a half million men with 150,000 cavalry but abandoned the “western capital”. The next year the Mongols went north and looted the Jin “eastern capital”, and in 1213 they besieged the “central capital”. In 1214 the Jin made a humiliating treaty but retained the capital. That summer, Jin Emperor Xuānzōng (宣宗) abandoned the central capital and moved the government to the “southern capital” of Kaifeng, making it the official seat of Jin Dynasty power. In 1216 a war faction persuaded Xuānzōng to attack the Song, but in 1219 they were defeated at the same place by the Yangtze River, where Prince Hǎilíng had been defeated in 1161. Jin Emperor Āizōng (哀宗) won a succession struggle against his brother and then quickly ended the war and went back to the capital. He made peace with the Tanguts, who had been allied with the Mongols. Genghis Khan died in 1227 while his armies were conquering the Western Xia Dynasty. His son Ögedei Khan invaded the Jin Empire in 1232 with assistance from the Southern Song. The Jurchens tried to resist; but when Kaifeng was attacked, Āizōng fled south. The Mongols looted the capital in 1233, and the next year Āizōng committed suicide to avoid being captured, ending the Jin dynasty in 1234.
In his book Empire of The Steppes, Grousset reports that the Mongols were always amazed at the valor of the Jin warriors, who held out until seven years after the death of Genghis Khan himself.
In the years of 1211 and 1212 Chenggis Khan's armies occupied more and more territory of the Jin empire and attacked the Jin capitals, but withdrew after plundering the cities. In the turmoil, Prince Weishao was murdered by general Heshi Liezhizhong 紇石烈執中 and replaced with Wanyan Xun 完顏珣 (posthumous Jin Xuanzong 金宣宗). Chenggis Khan withdrew from the beleaguered capital Yanjing when Wanyan Xun presented him Princess Qiguo 歧國公主. The powerless emperor decided to shift the capital to the south, to Kaifeng, the old capital of Northern Song. The Mongols soon occupied Yanjing. Peasant armies rose up against the Jin government, called Hongaojun 紅襖軍 "Red shirt armies", and landowners had to protect themselves against the intruding Mongol hords. From 1217 on the Ĵalaγir Muqali (Chinese: Muhuali 木華黎) took over the command of the Mongol troops to conquer the Jin empire. Under this pressure the Jin court under the leadership of chancellor Shuhu Gaoqi 術虎高琪 decided to withdraw further to the south after conquering the Southern Song territory. In 1218 Shuhu Gaoqi was executed after too many officials had pledged against the unsuccessful conquest campaigns. Two years later the Song court united with the Western Xia empire (Xixia 西夏) to extinguish the Jin Dynasty. In 1223 both the Mongol general Muqali and emperor Jin Xuanzong died. His successor Wanyan Shouxu 完顏守緒 (posthumous Jin Aizong 金哀宗) concentrated on the defense against the Mongols and was able to reconquer some territory. In 1227 the Mongols extinguished the Western Xia empire, and the death of the great Khan only prolonged the life of the Jin Dynasty for some years although the monk-general Wanyan Chen 完顏陳 was able to obtain several victories against the Mongol armies. Ögödei (Chinese: Wohuotai 窩闊台) and Tolui (Chinese: Tuolei 拖雷) personally lead the conquest of Jin, and in the battle of Sanfeng Mountain 三峰山 near Junzhou 鈞州 the Jin army was totally defeated. Kaifeng was beleaguered in 1234, and emperor Wanyan Shouxu fled to Caizhou 蔡州 where the emperor transferred the throne to Wanyan Chenglin 完顏承鱗 and committed suicide. The Jin Dynasty became history.