Fall of Kaifeng: the Jingkang incident and the end of the Northern Song

After the fall of the Liao the alliance between the Song and the Jin broke down over the frontier lands and the Song's dealings with former Liao commanders. In the autumn of 1125 the Jin invaded; early in 1126 its armies crossed the Yellow River and besieged Kaifeng. Emperor Huizong, who had pursued the alliance with the Jin, abdicated on 18 January 1126 in favour of his eldest son Qinzong and fled south. The Jin withdrew after the Song promised to cede three frontier prefectures and to pay an enormous indemnity, and after the emperor's brother Zhao Gou had been sent to the Jin camp as a hostage.

The respite was short. In the autumn of 1126, accusing the Song of inciting former Liao commanders against them, the Jin armies of Wanyan Zongwang and Wanyan Zonghan invaded again; Zongwang reached the walls of Kaifeng on 9 December, Zonghan eight days later. Few troops were left in the city, and relief armies could not break through. The court put its trust in Guo Jing, who claimed he could summon divine soldiers by magic: on 9 January 1127 he had the defenders leave the walls and led his men out of the Xuanhua Gate, they were routed, and the Jin troops mounted the walls. Qinzong went to the Jin camp outside the city to sue for peace; the Jin demanded vast sums in gold, silver and silk, and from February they kept him in their camp. On 20 March 1127 they ordered the Zhao house to be replaced, the next day Huizong too was brought to the camp, and on 20 April the minister Zhang Bangchang was made emperor of a puppet state of Chu.

On 10 May Huizong and on 13 May Qinzong, with the empress, the crown prince and much of the imperial clan, were led away north. According to the History of Song, the Jin also carried off the imperial carriages, regalia and ritual vessels, the instruments of the court orchestras, the armillary sphere and water clocks, the books of the palace libraries and the maps of all the prefectures, together with officials, palace women, eunuchs, artisans and entertainers. The two emperors lived out their lives as prisoners in the north-east: Huizong died at Wuguocheng in 1135, Qinzong in 1156. Huizong's ninth son, Zhao Gou, who had been outside the capital, was enthroned at Yingtianfu (present-day Shangqiu) on 12 June 1127 and became the first emperor of the Southern Song, which from 1138 had its capital at Lin'an (Hangzhou). Remembered as the ‘humiliation of Jingkang’ after the era name, the fall of Kaifeng left northern China to the Jin for more than a century.