Jin campaigns against the Song Dynasty

The Jurchen campaigns against the Song Dynasty were a series of wars that took place in the twelfth and thirteenth centuries between the Jurchen Jin Dynasty (1115–1234) and the Chinese Song Dynasty (960–1279). In 1115 the Jurchens rebelled against their overlords the Khitans of the Liao Dynasty (907–1125), and declared the formation of the Jin. Allying with the Song against their common enemy the Liao, the Jin promised to return to the Song nineteen heavily fortified prefectures in northern China that had fallen under Liao control since 938. The Jurchens' quick defeat of the Liao combined with Song military failures made the Jin reluctant to cede these territories. After a series of failed negotiations that embittered both sides, the Jurchens attacked the Song in November 1125, dispatching one army towards Taiyuan and the other towards Kaifeng, the Song capital.

Surprised by the news of an invasion, the Song general stationed in Taiyuan retreated from the city, which was besieged and later captured. As the second Jin army approached the capital, Emperor Huizong of the Song abdicated and fled south. A new emperor, Qinzong, was enthroned. The Jurchens began a siege against Kaifeng in 1126, but Qinzong negotiated for their retreat from the capital after he agreed to pay a large annual indemnity. Qinzong reneged on the deal and ordered Song forces to defend the prefectures instead of fortifying the capital. The Jin resumed their war against the Song and again besieged Kaifeng in 1127. The Chinese emperor was captured in an event known as the Jingkang Incident, the capital was looted, and the Song lost northern China to the Jin. Remnants of the Song retreated to southern China where they established Nanjing as their first temporary capital, before eventually relocating to Hangzhou. The retreat of the Song court marked the end of the Northern Song era and the beginning of the Southern Song.

The Jurchens tried to conquer southern China, but they were bogged down by a pro-Song insurgency in the north and a counteroffensive by the Song general Yue Fei. Yue regained some territories but retreated on the orders of the Southern Song emperor, who supported a peaceful resolution to the war. The Treaty of Shaoxing in 1142 settled the boundary between the two empires, but conflicts between the two dynasties continued until the fall of the Jin in 1234. A campaign against the Song by the fourth Jin emperor, Emperor Hailing, was unsuccessful. He lost the Battle of Caishi (1161) and was later assassinated by his own disaffected officers. An invasion of the Jin motivated by Song revanchism (1206–1208) was also unsuccessful.

Battles between the Song and Jin brought about the introduction of various gunpowder weapons. The siege of De'an was the first recorded appearance of the fire lance, an early ancestor of firearms. The Jurchen tribes were the ruling minority of an empire that was predominantly inhabited by subjects of the former Northern Song. Jurchen migrants settled in the conquered territories and assimilated with the local culture. The Jin government instituted a centralized imperial bureaucracy modeled on previous Chinese dynasties, basing their legitimacy on Confucian philosophy. The Mongol invasions of the 13th century ended both the Jin and Song dynasties.

Background


The Jurchens were a Tungusic-speaking group of semi-agrarian tribes inhabiting Manchuria. Many of the Jurchen tribes were vassals of the Liao Dynasty, ruled by the nomadic Khitans. To the south of the Liao was the Han Chinese Song empire, which had been founded in 960 by Zhao Kuangyin (later crowned Emperor Taizu). In 1114, the chieftain Wanyan Aguda united the disparate Jurchen tribes and led a revolt against the Liao. In 1115 he named himself emperor of the Jin Dynasty, adopting the Chinese name for gold.

The Song, after being informed in 1115 of the success of the Jurchen uprising by a Khitan defector, allied with the Jurchen rebels against the Liao, forming the Alliance Conducted at Sea. The alliance was named after the diplomatic exchanges that had to occur by traveling across the sea because the land routes were controlled by the Liao. Negotiations for an alliance began secretly under the pretense that the Song wanted to acquire horses from the Khitans. Song diplomats met with Aguda in 1118, while Jurchen diplomats arrived in the Song capital in 1119. The Jurchens settled on an agreement with the Song and offered parts of the Sixteen Prefectures to the Song in exchange for military support against the Liao and annual tributary payments. The Song wanted to acquire the entirety of the Sixteen Prefectures. The prefectures, nineteen in total, had been annexed by the Liao since 938 from the Shatuo Turk Later Jin Dynasty. Originally, the two sides had planned a joint attack against the Khitans by 1121, but it was rescheduled to 1122. Aguda was also growing increasingly frustrated as he realized that the Song intended to seize a larger share of the territory than had been promised.

Song resources were diverted to fighting the Western Xia and suppressing a popular rebellion while plans were being drawn up for an invasion of the Liao. The military leadership was impotent and squandered their advantages. The Song delayed their entry into the war, and when an army finally attacked in 1121 and 1122 under the command of the Chinese general and eunuch Tong Guan, the weakened Liao's smaller forces repelled the invaders with ease. They were forced to retreat twice back to the Song capital of Kaifeng. The Jurchens captured the main Khitan capital on February 23, 1122, while their Chinese allies suffered a series of military defeats against the Liao. In 1125, the Jurchens captured Tianzuo, the last emperor of the Liao Dynasty, near the Ordos Desert. A Khitan leader of the Liao court, Yelü Dashi, declared himself a prince and fled west to Xinjiang where he established the Kara-Khitan Khanate, also known by the dynastic name of Western Liao.

The collapse of the Liao led to negotiations between the Song and the Jin. Jurchen and Song representatives debated the terms of the first of the Song–Jin treaties. The Jurchen success against the Khitans and control of the Sixteen Prefectures gave them more leverage than the Song during the negotiations. Only a portion of the prefectures were returned to the Song, and the Song had to pay an annual indemnity of 300,000 packs of silk and 200,000 taels of silver. This sum included the indemnity that the Chinese previously paid to the Liao combined with the tax revenue that the Jurchens would have earned had they not returned the prefectures.

Campaigns against the Northern Song
The Jurchens conducted their campaigns against Song China soon after the capture of the last Khitan king in early 1125. The Jin emperor Taizong, successor and brother of Aguda, granted autonomy to the Jurchen generals, whose military actions no longer required the approval of the imperial court. The generals were angered by the military ineptitude of the Song and the series of failed diplomatic negotiations. Further exacerbating tensions was the incident of Zhang Jue in 1123. Zhang was a former Liao governor who was responsible for assassinating a Liao defector who had sided with the Jin. Zhang then took refuge with the Song, who reappointed him governor. The Song consented to the Jurchen request of executing Zhang, but the gesture was too late. The Jurchens decided to end the alliance with the Song and began preparations for an invasion.

Siege of Taiyuan
In November 1125 the Taizong emperor ordered his armies to attack the Song. The defection of Zhang Jue two years earlier served as the casus belli for the declaration of war. Two armies were sent to capture the major cities of the Song in late 1125. The western army, led by Wanyan Zonghan, headed towards Taiyuan through the mountains of Shanxi, on its way to the Song western capital Luoyang. It besieged Taiyuan in mid January 1126. The Song forces were not expecting an invasion and were caught off guard. The Chinese general Tong Guan was informed of the military expedition by an envoy he had sent to the Jin to obtain the cession of two prefectures. The returning envoy reported that the Jurchens were willing to forgo an invasion if the Song ceded their control of Hebei and Shanxi. Tong Guan retreated from Taiyuan and left command of his troops to Wang Bing. Taiyuan held on long enough to stop the Jurchen troops from advancing to Luoyang, but the city fell in late 1126.

Meanwhile the eastern army, commanded by Wanyan Zongwang, was dispatched towards Yanjing and eventually Kaifeng, capital of the Song Dynasty. It did not face much armed opposition. In 1125, Zongwang easily took Yanjing, modern Beijing, where the general Guo Yaoshi had switched his allegiances to the Jin. The city was the former Khitan Southern Capital, and had been handed to the Song after the defeat of the Liao. By December, the army had seized control of two prefectures and re-established Jurchen rule over the Sixteen Prefectures. The eastern army was nearing Kaifeng by early 1126.

First siege of Kaifeng
The Jurchen forces sent to Kaifeng reached the Yellow River on January 27, 1126. Fearing the approaching Jin army, Huizong planned to retreat to southern China. The emperor deserting the capital would have been viewed as an act of capitulation, so court officials convinced Huizong to abdicate. There were few objections. Rescuing an empire in crisis from destruction was more important than preserving the rituals of imperial inheritance. He was demoted to the ceremonial role of Retired Emperor. On January 28, Huizong abdicated and left the throne to his son Emperor Qinzong. Huizong departed the capital and escaped to the south.

Kaifeng was besieged on January 31, 1126. The commander of the Jurchen army promised to spare the city if the Song submitted to Jin as a vassal; forfeited the prime minister and prince as prisoners; ceded the Chinese prefectures of Hejian, Taiyuan, and Zhongshan; and offered an indemnity of 50 million taels of silver, 5 million taels of gold, 1 million packs of silk, 1 million packs of satin, 10,000 horses, 10,000 mules, 10,000 cattle, and 1,000 camels. The city was surrounded by the Jin army and there was little prospect of help from afar arriving. It would have taken 180 years for the Song to finishing paying a tribute of that size. Infighting broke out in the court between the officials who supported the Jin offer and those who opposed it. Opponents of the treaty rallied around the proposal of hunkering down until reinforcements arrived and Jurchen supplies ran out. They botched an ambush against the Jin that was carried out at night, and were replaced with officials who supported negotiating for peace. The defeat of the army in the ambush pushed Qinzong into meeting the Jurchen demands, and the officials convinced Qinzong to go through with the deal. and The Song recognized Jin control over the three prefectures. The Jurchen army retreated, ending the siege on March 5 after 33 days.

Emperor Qinzong reneged on the deal and dispatched two armies to repel the Jurchen troops attacking Taiyuan and bolster the defenses of Zhongshan and Hejian. The Song army of 90,000 soldiers and the other army of 60,000 were defeated by the Jin forces by June. The second expedition that tried to rescue Taiyuan was also unsuccessful. The siege of Taiyuan ended after 260 days, and the provincial capital fell to the Jurchens. By December 15, the Jurchen army that had conquered Taiyuan arrived in Kaifeng, where it joined the Jurchen forces besieging the Song capital.

Second siege of Kaifeng
Emperor Qinzong, who wanted to negotiate a truce with the Jurchens, left the capital Kaifeng barely defended with fewer than 100,000 soldiers. Qinzong committed a massive strategic blunder when he, unaware of the importance of the capital city, commanded that the armies of the empire must protect the prefectures instead of Kaifeng. The Song forces were dispersed throughout China, powerless to stop the second Jurchen siege of Kaifeng. The Jin, realizing the weakness of the Song, accused the Song of violating the peace treaty and launched a second military expedition. On January 9, 1127, a Jurchen assault on the city had commenced. Unlike the Jin, the Song did not dispose of their corpses, which made it appear that Song casualties were higher when the reverse was true. The morale of the Song soldiers was on the decline. The Jurchens broke through and looted the conquered city that day, and the city capitulated days after. Emperor Qinzong tried to appease the victorious Jurchens by offering the remaining wealth of the city. The royal treasury was emptied and the belongings of the city's residents were seized. Qinzong, the former emperor Huizong, and members of the Song court were captured and imprisoned by the Jurchens as hostages. They were taken north to Manchuria, where they were stripped of their royal privileges and reduced to commoners. The former emperors were humiliated by their captors. They were mocked with disparaging titles like "Muddled Virtue" and "Double Muddled". The Jin made them perform a ritual meant for war criminals in 1128. The harsh treatment of the Song royalty softened after the death of Huizong. Titles were granted to the deceased king and his son Qinzong was promoted to Duke, a position with a salary.

The Jin Dynasty did not expect or desire the fall of the Northern Song Dynasty. Their intention was to weaken the Song in order to demand more tribute, and they were unprepared for the magnitude of their victory. The Jurchens installed a former Song Dynasty official, Zhang Bangchang, as the puppet emperor of a newly established Da Chu dynasty. Zhang reigned for a short duration before the Song commanded his execution. He was coerced into suicide, a move that showed that the Song still retained some influence in northern China and that the Jin had yet to solidify their control of the new territories.

The Jin had hoped that a puppet state would be capable of administering northern China and collecting the annual indemnity without provoking a rebellion by the native Han Chinese. The move did not deter the resistance of the Han Chinese, who were motivated by their anger towards the looting by the Jurchens rather than by a sense of loyalty towards the inept Song court. A number of Song commanders, stationed in towns scattered across northern China, retained their allegiance to the Song, and militias were organized by armed volunteers opposing the Jurchen military presence. The insurgency slowed the southern advance of the Jin Dynasty.

Fall of the Northern Song
Many factors contributed to the Song Dynasty's repeated military blunders and subsequent loss of northern China to the Jurchens. Traditional accounts of Song history held the venality of Huizong's imperial court responsible for the decline of the dynasty. These narratives condemned Huizong and his officials for their moral failures. Early Song Dynasty emperors were eager to enact political reforms and revive the ethical framework of Confucianism, but the enthusiasm for reforms gradually died after the reformist Wang Anshi's expulsion as Prime Minister in 1076. Corruption marred the reign of Emperor Huizong, enthroned in 1100, who was more skilled as a painter than as a ruler. Huizong was known for his extravagance, and funded the costly construction of gardens and temples while rebellions threatened the state's grip on power. A modern analysis by Ari Daniel Levine places more of the blame on the deficiencies in the military and bureaucratic leadership. The loss of northern China was not inevitable. The military was overextended by a government too assured of its own military prowess. Huizong diverted the state's resources to failed wars against the Western Xia. The Song insistence on a greater share of Liao territory only succeeded in provoking their Jurchen allies. Song diplomatic oversights underestimated the Jin and allowed the unimpeded rise of Jurchen military power. The state had plentiful resources, with the exception of horses, but managed its assets poorly during battles. The Song military lacked a consistent supply of horses, giving the dynasty a significant disadvantage against the mounted steppe nomads. Unlike the expansive Tang and Han empires that preceded the Song, the Song Dynasty did not have a significant foothold in Central Asia where a large proportion of its horses could be bred or procured.

Southern retreat of the Song court
The Jin sought to completely destroy the Song after their victory at Kaifeng. The attempt to displace the Song was not successful. At least one prince of the Song Dynasty, Zhao Gou who later was enthroned in 1127 as Emperor Gaozong of Song, had escaped capture. The future emperor managed to evade the Jurchen troops tailing him by moving from one province to the next. The Jurchens tried to lure him back to Kaifeng where they could finally capture him, but did not succeed. The remainder of the Song court retreated south after the conquest of northern China. The move marked the end of the Northern Song and the beginning of the Southern Song era of Chinese history, with the city of Nanjing, modern Shangqiu, as the first in a series of temporary capitals called xingzai. The court moved to Nanjing because of its historical importance to Emperor Taizu of Song, the founder of the dynasty, who had previously served in the city as a military governor. The symbolism of the city was meant to secure the political legitimacy of the new emperor, who was crowned emperor of China in Nanjing on June 12, 1127.

The Song court retreated south once more from Nanjing to Yangzhou while the Jurchens marched after them. The court spent over a year in the city between 1128 and 1129, before moving to Hangzhou in 1129. The Jin advance stopped at the Yangtze River, but the Jurchens continued to stage raids against Song settlements further south. Hangzhou was declared the new capital in 1132, and would remain the capital of the Southern Song for the next 150 years, despite the Song court's treatment of the city as just a temporary capital. The city was chosen for the natural barriers that surrounded it, including lakes and rice paddies, which made it more difficult for the Jurchen cavalry to breach Hangzhou's fortifications.

The retreat to southern China led to major demographic changes. The population of refugees from the north that resettled in Hangzhou and Nanjing had grown greater than the population of original residents, whose numbers had dwindled from repeated Jurchen raids. The government encouraged the resettlement of peasant migrants from the southern provinces of the Song to the underpopulated territories between the Yangtze and the Huai Rivers. Hangzhou grew into a major commercial and cultural center of the Song Dynasty. It rose from a middling city of no special importance to one of the world's largest and most prosperous. Marco Polo remarked that "this city is greater than any in the world" during his stay in the Yuan Dynasty, when the city was not as wealthy as during the Song. Once retaking northern China became less plausible and Hangzhou grew into a significant city for trade, the government buildings were extended and renovated to better befit its status as a genuine imperial capital and not just a temporary one. The imperial palace in Hangzhou, modest in size, was expanded in 1133 with new roofed alleyways and in 1148 with an extension of the palace walls.

Wars with the Southern Song
After the fall of Kaifeng in 1127, Jurchen forces continued to cross the Yangtze River and invade southern China. When they neared Hangzhou on January 26, 1130, the Song court fled on ships to islands off the coast of Zhejiang, and later to the city of Shaoxing. The court returned to Hangzhou in 1133 after the Jurchens finished pillaging Hangzhou and retreated. The continuing insurgency in northern China hampered the Jurchen campaigns south of the Yangtze. Reluctant to let the war drag on, the Jin decided to create the state of Qi, a puppet state in northern China. The Jurchens believed that the state, nominally ruled by someone of Han Chinese descent, would be able to attract the allegiance of disaffected members of the insurgency. The Jurchens also suffered from a shortage of skilled manpower, and controlling the entirety of northern China was not administratively feasible.

In the final months of 1129, the Jurchens enthroned Liu Yu as the emperor of the Qi state. Liu was a Song official from Hebei who had been a prefect of Jinan in Shandong before his defection to the Jin in 1128. Daming in Hebei was the first capital of Qi prior to its move to Kaifeng, former capital of the Northern Song, in 1132. The Qi government instituted military conscription, made an attempt at reforming the bureaucracy, and enacted laws that enforced the collection of high taxes.

General Yue Fei's counteroffensive
The Jin's push southward was halted by a Song campaign led by the general Yue Fei. His defense of the Southern Song made him a national hero. The son of an impoverished farmer, he had joined the military in 1122. Early in his career, he fought against local Chinese warlords who were looting northern China; their suppression was necessary for the continued resistance against the Jurchens. Yue participated in the second siege of Kaifeng in 1127. After Kaifeng fell, he joined an army in Jiankang tasked with defending the Yangtze. This army prevented the Jurchens from advancing to the river in 1129.

Yue Fei's rising reputation as a military leader attracted the attention of the Song court. In 1133, he was made the general of the largest army near the Central Yangtze. Between 1134 and 1135, he commanded the counteroffensive that defeated the state of Qi and recaptured the territories conquered by the Jurchens. By 1137, the emperor of Qi had his title reduced to that of a prince and the Jin puppet state was dissolved.

Yue Fei led military expeditions against the Jurchens that achieved large territorial gains. When a Jurchen army led by Wanyan Wuzhu invaded in May 1139, Yue was assigned to head the Song forces defending the city of Huainan. Wanyan retreated to Kaifeng instead of advancing to Huainan, and Yue's army followed him into Jin territory, disobeying an order by Gaozong that forbid Yue from going on the offensive against the Jurchens. Yue captured Zhengzhou and sent soldiers across the Yellow River to stir up a peasant rebellion against the Jin. In the Battle of Yancheng, Wanyan launched a surprise attack on the Song forces in Yancheng on July 8, 1139 with an army consisting 100,000 infantry and 15,000 horsemen. Yue Fei directed his cavalry to attack the Jurchen soldiers. The Jin army was defeated and the battle was a decisive victory for Yue Fei. Yue continued on to Henan, where he recaptured Zhengzhou and Luoyang. By 1140, he was forced to withdraw after the emperor ordered him to return to the Song court.



The real Yue Fei differed from the later myths that grew from his exploits. The portrayal of Yue as a scholar-general is only partially true. He was a skilled general, and may have been semiliterate in Classical Chinese, but he was not an erudite Confucian scholar. Contrary to traditional legends, Yue was not the sole Chinese general engaged in the offensive against the Jurchens. He was one of many generals that fought against the Jin in northern China, and some of his peers were members of the scholarly elite. Many of the exaggerations of Yue Fei's life can be traced to a biography written by his grandson, Yue Ke. Yue Fei's later status as a folk hero emerged in the Yuan Dynasty and had a large impact on Chinese culture. Temples and shrines devoted to Yue Fei were constructed in the Ming Dynasty. A Chinese World War II anthem alludes to lyrics said to have been written by Yue Fei.

Emperor Gaozong supported a peace treaty with the Jurchens and sought to rein in the assertiveness of the military. The military expeditions of Yue Fei and other generals were an obstacle to negotiations for peace. The government weakened the military by demoting the generals and rewarded them with different titles. Yue Fei resisted by announcing his resignation as an act of protest. He was imprisoned in 1141 and poisoned a year later. Jurchen diplomatic pressure during the peace negotiations may have played a role.

Treaty of Shaoxing
On October 11, 1142 the Treaty of Shaoxing was ratified, ending the conflict between the Jurchens and the Song. By the terms of the treaty, the Huai River, a river north of the Yangtze, was designated as the boundary between the two empires. The Song agreed to pay a yearly tribute of 250,000 taels of silver and 250,000 packs of silk to the Jurchens. The peace ensured by the Shaoxing treaty was interrupted during two occasions after 1142. One campaign was initiated by the Song and the other by the Jin.

The treaty reduced the Southern Song's status to a Jin vassal. The document designated the Song as the "insignificant state," while the Jin is recognized as the "superior state". The text of the treaty was not recorded in Chinese records of the event, a sign of its humiliating reputation. The contents of the agreement were recovered from a Jurchen biography. Once the treaty had been settled, the Jurchens retreated and returned north, and trade resumed between the two empires.

Emperor Hailing's campaign
Emperor Hailing, fourth emperor of the Jin Dynasty, began an invasion in 1161 but never formally declared war. Notified beforehand of the plan, the Song prepared by securing their defenses along the border, especially near the Yangtze River. Jurchen armies left Kaifeng on October 15, reached the Huai River border on October 28, and marched in the direction of the Yangtze. The Song lost the Huai to the Jurchens but captured a few Jin prefectures in the west, slowing the Jurchen advance. A group of Jurchen generals were sent to cross the Yangtze River around the city of Caishi in Anhui while Hailing established a base near Yangzhou.

The Jurchen army was defeated while attacking Caishi between November 26 and 27 during the Battle of Caishi. Traditional Chinese accounts consider this the turning point of the war, characterizing it as a military upset that secured southern China from the northern invaders. The significance of the battle is said to have rivaled a similarly revered victory at the Battle of Fei River in the 4th century. Contemporaneous Song accounts of the war claimed that the 18,000 Song soldiers tasked to defend Caishi were able to defeat the invading Jurchen army of 400,000 soldiers. Modern historians are more skeptical, and consider the Jurchen numbers an exaggeration. Song historians may have confused the number of Jurchen soldiers at the Battle of Caishi with the total number of soldiers under the command of Emperor Hailing. The conflict was not the one–sided battle that traditional accounts imply, and the Song had numerous advantages over the Jin. The Song fleet was larger than the Jin's, and the Jin were unable to use their greatest asset, cavalry, in a naval battle.

The Jin lost, but only suffered about 4,000 casualties and the battle was not fatal to the Jurchen war effort. A modern analysis of the battlefield has shown that it was a minor battle, although the victory did boost Song morale. Hailing's downfall was not determined by a single battle. It was his poor relationships with the Jurchen generals, who despised him, that doomed the chances of a Jin victory. The war ended on December 15 after Hailing was assassinated by disaffected officers in a military camp.

Song revanchism
The Jin were weakened by the pressure of the rising Mongols to the north, a Yellow River flood in 1194 that devastated Hebei and Shandong in northern China, and the droughts and swarming locusts that plagued the south near the Huai. The Song were informed of the Jurchen predicament through their embassies in the Jin capital, and started provoking their northern neighbor in 1204 and onward by raiding Jin settlements. These early clashes continued to escalate, partly abetted by Song officials in support of revanchism, and war against the Jin was officially declared on June 14, 1206. The document that announced the war claimed the Jurchen lost the Mandate of Heaven, a sign that they were unfit to rule, and called for an insurrection of Han Chinese against the Jin state.

Song armies captured the barely defended city of Suzhou but suffered large losses against the Jurchens in Hebei. Soldier morale sank as weather conditions worsened, supplies ran out, and hunger spread, forcing many to desert. The massive defections of Han Chinese in northern China that the Song had expected never materialized. A notable betrayal did occur on the Song side, however: Wu Xi, the governor and general of Sichuan, defected to the Jin in 1206. The act would have meant a loss of the entire western frontier of the war had Song loyalists not assassinated Wu, which they did on March 29, 1207. The Song advance was impeded by Jin military successes. By the fall of 1206, the Jurchens had captured multiple towns and military bases.

Since neither combatant was eager to continue the war, a peace treaty was signed on November 2, 1208, and the Song tribute to the Jurchens was reinstated. The Song were obligated to pay an annual indemnity of 50,000 taels of silver and 50,000 packs of fabric. It was also stipulated that the Song had to present to the Jurchens the decapitated head of the Chinese minister who had instigated the war.

Rise of the Mongols
The Jin Dynasty shied away from further military expansion and was content with appeasement through tribute, similar to the practices of the Song. The Jin were occasionally threatened by raiding steppe nomads from the northwest. The most important of these nomadic confederations were the nascent Mongols, who began as a Jurchen tributary. As the Mongols expanded, the Jin suffered territorial losses and invaded the Song in 1217 to remedy their shrinking resources. Jurchen military successes were limited, and the Jin faced repeated raids from the neighboring state of Western Xia. A second invasion against the Song was conducted soon afterwards and did marginally better than the first. The Jin tried to extort an indemnity from the Song but never received it.

A peace treaty was negotiated with the Song in 1224 that ended the annual tributes to the Jurchens. Diplomatic relationships between the Jin and Song were also cut off. The Jin Dynasty collapsed when the Jurchens were defeated in a Mongol and Song siege of Caizhou in 1234. The Song Dynasty fell in 1279, when the remaining Song loyalists lost to the Mongols in a naval battle near Guangdong.

Cultural and demographic assimilation
The capital of the Jin Dynasty was moved to the south from Manchuria to Beijing in 1153. Jurchen migrants from Manchuria settled in the Jin-controlled territories of northern China. Constituting less than ten percent of the total population, the two to three million ruling Jurchens were a minority in a region that was still dominated by 30 million Han Chinese. The southward expansion of the Jurchens caused the Jin to transition their decentralized government of semi-agrarian tribes to a bureaucratic Chinese-style dynasty.

The Jin government initially promoted an independent Jurchen culture alongside their adoption of the centralized Chinese imperial bureaucracy, but the empire was gradually sinicized over time. The Jurchens became fluent in the Chinese language, and the philosophy of Confucianism was used to legitimize the ruling government. The Khitan script, from the Chinese family of scripts, formed the basis of a national writing system of the empire, the Jurchen script. All three scripts were working languages of the government. Jurchen clans adopted Chinese personal names with their Jurchen names. Emperor Hailing of the Jin was an enthusiastic proponent of Jurchen sinification and enacted policies to encourage it. Hailing had been acculturated by Song diplomats from childhood, and his emulation of Song practices earned him the Jurchen nickname of "aping the Chinese". He studied the Chinese classics, drank tea, and played Chinese chess for recreation. Under his reign, the administrative core of the empire was moved south from Manchuria. Palaces were erected in Beijing and Kaifeng, and the Manchurian residences of Jurchen chieftains were demolished.

The emperor's political reforms enforced the adoption of Chinese governance and culture. His sinification policies were connected with his desire to conquer all of China and legitimize himself as a Chinese emperor. The prospect of conquering southern China was cut short by a coup against Hailing on December 15, 1161 that resulted in his assassination. Hailing's successor, Emperor Shizong, was less enthusiastic about sinicization and reversed several of Hailing's edicts. He sanctioned new policies with the intent to slow the assimilation of the Jurchens. Shizong's prohibitions were abandoned by Emperor Zhangzong. Zhangzhong promoted reforms that transformed the political structure of the dynasty closer to that of the Song and Tang dynasties. Despite cultural and demographic changes, the hostilities between the Jin Dynasty and the Southern Song persisted for the remainder of both empires.

Gunpowder warfare
The battles between the Song and the Jurchens spurred the invention and use of gunpowder weapons. The fire lance, one of the earliest ancestors of the firearm, was used by the Song against the Jurchen siege of De'an in 1132. The weapon consisted of a spear attached with a flamethrower capable of firing projectiles from a barrel constructed of bamboo or paper. Later fire lances used metal barrels and fired projectiles farther and with greater force.

An early rudimentary bomb called the huopao, filled with gunpowder and propelled with a trebuchet, was also in use as an incendiary weapon. The huopao was used by the defending Song army during the first Jurchen siege of Kaifeng in 1126. In 1127, huopao were employed by Song forces against the Jurchens in Hebei. At the Battle of Tangdao in 1161, the Song navy fired huopao against the Jurchen fleet of 600 ships. The Song were victorious in the battle, and also in the battle of Caishi later on in the year where the army deployed gunpowder bombs. A bomb cast with pig-iron called the tieuhuopao was used by the Jurchens in 1221.