In the fourth year of Song Xuanhe, the Song army swept the Zhongjing Road and Xijing Road of the Liao Dynasty according to the agreement, led by Tong Guan and Cai You to attack Liao in two ways, the East Route Army led by Chongshi Dao to Baigou, and Xin Xingzong led the West Route Army to Fancun. He was also regarded as the lord of the Liao Dynasty, and Yelu Chun, who was sitting in Nanjing's Xijin Mansion, sent Yelu Dashi and Xiao Gan to lead troops to resist.

In May, the Liao Mourning Army, which was already in the West Mountains and was about to die, actually defeated the Yang Keshi Division, the vanguard of the Song West Route Army, and the Xinxing Sect Division, the East Road Army. The Song army suffered many casualties, and had to retreat in the direction of Xiongzhou, and the Liao army gathered elite cavalry to chase and kill, and the Song army led by the seed master Dao fought a bloody battle outside the city of Xiongzhou. In the face of the Liao army's crazy counterattack and the sudden blow of the hail, the Song army was scattered on all fronts, from the south of Xiongzhou, the north of Mozhou, between Tangbo, and the west of Xiongzhou, Baozhou and Zhending, the dead bodies pillowed each other, and they were invincible. The rest of the Liao army in the area north of Xiongzhou actually showed off its might, and then the division returned, and the Liao Dynasty was in Nanjing.

The soldiers and horses of the Liao Dynasty, which was originally at the time of life and death, used the power of mourning soldiers to defeat the Song army, which thought it was bound to win, which undoubtedly boosted the morale of the officers and men in the army. However, supported by the ministers, Yelu Chun, who was called Emperor Tianxi, also died of illness at the time of the life and death of the Liao Dynasty, and the edict set up the fifth son of Tianzuo Emperor Yelu Yanxi, Qin King Yelu Ding, as the emperor, but now Yelu Ding still stayed with Yelu Yanxi, who fled to the Yinshan area, and Yelu Chun's widow Concubine Xiao Puxian was respected as the queen mother and called the regent.

Tong Guan, who was anxious to capture Nanjing of the Liao Dynasty, sent people to secretly communicate with Li Chuwen, a powerful minister of the Song Dynasty, who planned to belong to the Song Dynasty, and the Song army also gathered troops and horses to march to Xijin Mansion again. Subsequently, Gao Feng of Liaoyi Prefecture, Xiao Qingyu and other military generals successively descended to the Song Dynasty, Xiao Puxian knew that the situation was critical, and it was really difficult to return to the sky, and after discussing with the courtiers of Xijin Mansion, he was called a minister to Song and Jin, and expressed his willingness to surrender, just to retain the power of the Liao Dynasty to be complete.

After Zhao Ji got the report in the Song Dynasty, he thought that the land of Yanyun in the Nanjing region of the Liao Dynasty was about to be recovered, and he was Longyan Dayue, so he waved his pen and analyzed the Tianjin Mansion to make Yanshan Mansion (Yanjing), and changed the names of other military states. But instead of accepting the Liao Dynasty's invitation to call the ministers and quit the army, now that the general trend has been decided, why not wave the army to conquer Yanjing in one fell swoop? First of all, the Song army of Yang Keshi and Gao Shixuan's department attacked Yanjing at night, and under the guidance of Nei Ying, they brazenly entered the city.

However, the Song army, which thought that the situation had been decided, rushed into the city and plundered property, wanton and even slaughtered the Khitan and Xi people, and the Han people in the city were also looted and plundered, and the people of the city even together with a large number of Han people who identified with their Liao identity aroused resistance, and fought fierce street battles with the remaining Liao army and the Song army, Yang Keshi fled in embarrassment, Gao Shixuan and other soldiers died in the city, and only a few hundred of the six thousand elite soldiers were scattered and fled. As for the Song army, which was still outside Yanjing City, it ran into the Liao Dynasty Zhibei Yuan's privy council when he heard that Yanjing was lost, and he also commanded the troops of Xiao Gan's troops and horses......

Xiao Gan led his troops to intercept the Song army's grain road, and the night attack broke Liu Yanqing, Liu Guangshi's troops and horses, the Song defeated army disturbed and routed, trampled on each other, and the number of people who fell into the cliff stream was unknown, Xiao Gan waved the army again to pursue, and the Song army fought in Baigou again, the Song army was as defeated as before, and fled to Xiongzhou, and was no longer able to capture Yanjing......

The Western Army that exterminated the Manichaean uprising in Jiangnan was originally the elite division that the Song court relied on the most, but it was defeated one after another by the remnants of the Liao army, which was far beyond the surprise of Tong Guan and even the Song court ministers who tried their best to promote the destruction of Liao. As for the reasons for the defeat, in addition to the fact that the Western Army was transferred to the south and the north, the generals were tired, and the Heshuo Forbidden Army, which was also the main force of the Liao invasion, was not strong enough, and it also underestimated the huge combat power of the Liao Dynasty in a desperate situation, and the discerning people also knew very well that the two fiascos were also related to Tong Guante's over-eagerness to achieve results, and the same undercurrent between the factions of the generals of the Western Army.

And Yelu Dashi and Xiao Gan, two famous generals who successively won great victories in the battles to defeat the Song army in the defense of the Liao Dynasty in Nanjing, at least at this stage, the shock caused to the Song people was not inferior to that of Yelu Xiuge, Yelu Xianzhen and other famous generals who had repeatedly defeated the Song army when the Song and Liao wars were frequent.

Originally, according to the agreement of the Song and Jin, the Song army mainly attacked the Nanjing Province of the Liao Dynasty, while the Jin army focused its attack on annexing the vast territory of the West Jingdao of the Liao State, and each other's offensive directions had their own focuses. However, when the Song army had been defeated one after another, and even Tong Guan, who was still planning to recover the land of Yanyun and satisfy his ambition of becoming the king and the lord, took the initiative to send envoys to ask the Jin army to go south to capture the land of Yanyun.

Since there are strong reinforcements that can take Yanjing on their behalf, it is okay to spend a lot of money to redeem Yanjing and other places, and they can still recover the credit of Yanyun and get rewarded by the imperial court, as for the impact of spending the treasury and asking the Jin army to attack Liao on their behalf, these are not within Tong Guan's consideration......

The weakness of the Song army's combat strength and the attitude of the Song envoys were unexpectedly unexpected by the ministers and generals of the Jin State, and the attitude of the vast majority of Jurchen leaders below Wanyan Aguta towards the Song court underwent a subversive change. This is still based on the fact that the Jin State did not intend to violate the treaty of the "Maritime Alliance" at first, but at the request of Tong Guan, the commander of the Song Army, asked his own soldiers and horses to go south to work on his behalf......

Finally, Yan Agu sent the edict to the Liao Dynasty Nanjing Dao Zhudi, claiming that the king had arrived, and those who surrendered would forgive his sins, and the officials were still the same, and ordered him to complete the two words Yan Lu Bu, Di Gu Nai, Yinshu Ge and other generals to lead the army to occupy Juyong Pass, and then went straight to Yanjing to kill with a momentum like a bamboo. Although the Northern Liao regime defeated the Song army twice, it knew that it was difficult to resist the Jin army, so it had to abandon the city and flee. Xiao Gan, who was originally the leader of the Xi clan, led the defeated army with his own clan as the main body to flee to Jianqi Mountain.

After the Jin soldiers entered Yanjing bloodlessly, they appeased the civil and military officials who surrendered to Northern Liao, and immediately sent soldiers and horses to search for the remnants of the Liao army. Originally, it was a wait-and-see who could be in the Song, Liao, and Jin forces around Yanjing, but from the current situation, many powerful armed forces who were based on the territory to protect themselves also began to tend to submit to the Jin side.

In addition to the Yelu Dashi who escorted Xiao Pu to Yinshan to meet Yelu Yanxi, and Xiao Gan, who led the Xi tribe to retreat and assemble, and seemed to have another move, the remnants of the Liao army who escaped from Yanjing were also killed by the Jin army's pursuers and scattered soldiers and horses......

However, at the same time, the two naval ships sent from the Baozhou area of eastern Liaodong and the Jeju Shuibo Liangshan on the Jingdong Road in the Song Dynasty met at Wuqing County in the south of Yanjing in Nanjing Province of the Liao Dynasty (later the area of Tanggu in Tianjin......