In October of that year, Zhao Kuangyin, Taizu of the Song Dynasty, sent an envoy to Taiyuan to persuade him to surrender, but Liu Jiyuan refused to surrender to the Song Dynasty on the one hand, and urgently sent an envoy to Liao to ask for help.

In November, Liao Muzong sent Ta'er, the commander of the Liao army's soldiers and horses, to lead a large army to rescue the Northern Han and force into Taiyuan. In terms of the Song army, although the army is hedgehog, Jinyang is surrounded by mountains on three sides, controlling mountains and rivers, the key points of the four stops, controlling the capital of the five plains, and winning in the shape of the world, since the Spring and Autumn Period and the Warring States Period, it is a first-class strategic place, and then it has been continuously repaired and strengthened by the dynasties, and it has already been impregnable.

At that time, Jinyang was the first important place of the Han Kingdom, and the three generations of the Northern Han Dynasty lords had never relaxed the city defense of Jinyang since the first day of the founding of the country.

Under the efforts of the three generations of lords of the Northern Han Dynasty, Jinyang City not only strengthened the city defense more than the previous dynasties, but also the grain and grass hoarded in the city were also very sufficient, enough to support more than a year, so although there were Song generals Li Jixun and others desperately attacked, but they could not be attacked for a long time.

In addition, when they heard that the Liao army was coming, they had no choice but to lead their troops south. The Northern Han army took the opportunity to launch a pursuit and plundered the Jin and Jiang states of the Song Dynasty.

In February of the following year, that is, in February of the second year of Song Kaibao (969), Zhao Kuangyin, who was unwilling to fail, ordered Cao Bin, Dang Jin and other generals to lead their troops to Taiyuan first, and led the army to follow and conquer the Northern Han Dynasty.

Liu Jiye of the Northern Han Dynasty learned that Zhao Kuangyin was personally driving, and he knew that he was outnumbered, so he shrank his forces and retreated to Taiyuan.

At the beginning of March, Zhao Kuangyin's troops went to Taiyuan, and then requisitioned tens of thousands of local migrant workers, built a long wall to surround Taiyuan, and built a long causeway, diverted Fen water to irrigate the city, and attacked in many ways.

As a result, Liu Jiyuan had to command the defenders to resist the attack of the Song army on the one hand, and then continue to ask Liao for help.

It happened to be at this point in time that on March 12 of that year, Yelu Jing, who was hunting in Montenegro, was killed by his attendants.

Subsequently, the son of the young Liao Shizong Yelu Ruan, who was only twenty-one years old, was supported by some of the four royal forces, Gao Xun, the privy envoy of the Southern Yuan of the old ministry of Sejong, the Flying Dragon Maid, and the Taizu Temple to stabilize Han Kuanghei, and the son-in-law of Liao Taizong Yelu Deguang, who was born in the descendants of the young father's house of the uncle of the Liao State, Xiao Siwen, the commander of the horse, and others supported him as the new emperor of the Liao State and changed the Yuan to Baoning.

From the Later Zhou Dynasty to the founding of the Northern Song Dynasty, whether it was the Later Zhou Dynasty of the Central Plains Dynasty or the Great Song Dynasty, the biggest reason for the failure of the Liao army at the most critical time of attacking Jinyang was because of the intervention of the Liao army.

Taking advantage of the turmoil within the Liao State, Zhao Kuangyin decided to seize this once-in-a-lifetime opportunity and command the Song army to step up the siege of the city.