The Jin–Song Wars are a series of conflicts between the Jurchen Jin dynasty (1115–1234) and Chinese Song dynasty (960–1279).

In 1115, the Jurchens had rebelled against their overlords, the Khitan Liao dynasty (907–1125), and declared the formation of the Jin.

Allying with the Song against their common enemy the Liao, the Jin promise to return to the Song the territories in northern China that had fallen under Liao control since 938.

The Jurchens' quick defeat of the Liao combined with Song military failures make the Jin reluctant to cede these territories.

After a series of failed negotiations that embitter both sides, the Jurchens attack 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 retreats from the city, which is besieged and later captured.

As the second Jin army approaches the capital, Emperor Huizong of the Song abdicates and flees south.

A new emperor, Qinzong, is enthroned.

The Jurchens begin a siege against Kaifeng in 1126, but Qinzong negotiates for their retreat from the capital after he agrees to pay a large annual indemnity.

Qinzong reneges on the deal and orders Song forces to defend the prefectures instead of fortifying the capital.

The Jin resume their war against the Song and again besiege Kaifeng in 1127.

The Chinese emperor is captured in an event known as the Jingkang Incident, the capital is looted, and the Song loses northern China to the Jin.

Remnants of the Song retreat to southern China and, after brief stays in several temporary capitals, eventually relocate yo Hangzhou.

The retreat of the Song court marks the end of the Northern Song era and the beginning of the Southern Song.The Jurchens tried to conquer southern China in the 1130s, but they are bogged down by a pro-Song insurgency in the north and a counteroffensive by the Song generals Yue Fei, Han Shizhong, and others.

The generals regain some territories but retreat on the orders of the Southern Song emperor, who supports a peaceful resolution to the war.

The Treaty of Shaoxing in 1142 settles the boundary between the two empires along the Huai River, but conflicts between the two dynasties will continue until the fall of the Jin in 1234.

A campaign against the Song by the fourth Jin emperor, Prince Hailing, is unsuccessful.

He loses the Battle of Caishi (1161) and is later assassinated by his own disaffected officers.

An invasion of the Jin motivated by Song revanchism (1206–1208) is also unsuccessful.

A decade later, the Jin launch an abortive military campaign against the Song in 1217 to compensate for the territory that they had lost to the invading Mongols.

The Song form an alliance with the Mongols in 1233, and in the following year jointly capture Caizhou, the last refuge of the Jin emperor.

The Jin dynasty collapses that year in 1234.

After the demise of the Jin, the Song dynasty itself becomes a target of the Mongols, and falls in 1279.The wars engendered an era of technological, cultural, and demographic changes in China.

Battles between the Song and Jin bring about the introduction of various gunpowder weapons.

The siege of De'an in 1132 is the first recorded appearance of the fire lance, an early ancestor of firearms.

There are also reports of battles fought with primitive gunpowder bombs like the incendiary huopao or the exploding tiehuopao, incendiary arrows, and other related weapons.

In northern China, the Jurchen tribes are the ruling minority of an empire that is predominantly inhabited by former subjects of the Northern Song.

Jurchen migrants settle in the conquered territories and assimilate with the local culture.

The Jin government institutes a centralized imperial bureaucracy modeled on previous Chinese dynasties, basing their legitimacy on Confucian philosophy.

Song refugees from the north resettle in southern China.

The north is the cultural center of China, and its conquest by the Jin diminishes the international stature of the Song dynasty.

The Southern Song, however, quickly return to economic prosperity, and trade with the Jin is lucrative despite decades of warfare.

The capital of the Southern Song, Hangzhou, expands into a major city for commerce.