With the issuance of the committee's order, the Beiping Army naturally immediately mobilized troops and transferred materials, so that the Left Route Army of the Northern Expedition could complete the formation and operation in the shortest possible time, and everything seemed to be in an orderly manner. The retreat from Muttel's side, however, ran into some troubles, did not go well, and the progress was noticeably not as fast as expected. The main reason for this situation is the interference and obstruction of the dozen or so small guerrilla troops of the Khitan army scattered between Jianzhou, Andezhou and Jinzhou. Although these small groups of marching troops were not large, each of them numbered more than 1,200,000 men, in terms of combat effectiveness alone, they did not pose any threat to Muttel's 5,000 cavalry, especially the "Ranger Battalion" and "Wolf Tooth Battalion", which included the most elite of the "Wyvern". However, as the saying goes, "the toad falls on the surface of the foot - it can't bite people but disgusts people", and the small group of guerrillant troops of the Khitan army could not pose a substantial threat and damage to Mutel's troops, but they could affect the process of his retreat, interfere with his marching order, and thus greatly delay his withdrawal to Jinzhou.

The problem is, time is of the essence for Muttel's ministry right now. On the one hand, Muttel had to return to Jinzhou before the Left Route Army left the fortress, and complete the replenishment and rest of his subordinates, so that he could carry out the task of attacking the Khitan Tokyo Road in a good state. On the other hand, at this time, Muttel's department was already in a state of shortage of grain and grass, and the longer the delay on the road, the closer it was to the unfavorable situation of running out of food. In addition, the retreat route of Muttel's division passed mainly through mountainous and hilly terrain, and the brigade could not be divided into multiple columns and march in unison to speed up the speed as in the plains. It can be said that this retreat of Muttel's unit can be called the most urgent, dangerous, and aggrieved since the formation of the "Flying Dragon Army", and it is also the first time that the troops have withdrawn without achieving a substantial victory.

Fortunately, although it took half the time longer than expected to complete the distance of less than 200 miles of more than 100 miles, although the soldiers were physically and mentally exhausted due to the harassment of the small group of Khitan guerrillant troops, and although the number of casualties in the retreat process was close to the number of the previous westward attack, Mutel's headquarters finally entered Jinzhou Yongle City almost at the same time as the first division and one regiment of the "Flying Dragon Army" that went north from Shanhaiguan on the fifth day after receiving the order to retreat. At this time, it was already the twelfth day of the seventh lunar month of the eighth year of Xiande.

A series of overt or covert adjustments on the side of the Beiping Army, especially the withdrawal of the Muttel Army's return to Jinzhou and the Lulongshan Battalion, made the Khitan Imperial Court, which had only seen the actions on the surface and had always been worried that the Beiping Army might do its best to go north in the Lulongshan Camp and attack Dading Mansion with the Muttel Army from the east, breathed a sigh of relief, and at the same time, the courage to fight and the morale of the army, which had fallen to the bottom, also recovered a little. Yelu Jing was complacent about the correctness and effectiveness of his previous order to clear the wilderness and attack the grain road, and rewarded Xiao Haili, the prime minister of the Khitan North Mansion who succeeded Yelu Tartlie who had been killed in battle, and commanded the soldiers and horses of Zhongjing Province, and Xiao Haili, who was the chief governor of military and state affairs, and who was deeply trusted by himself; At the same time, he began to ponder whether it was possible for his side to cut off the grain route of the Beiping army in Jinzhou in a similar way, so that the other side would retreat without a fight due to lack of food, so as to recapture the occupied prefectures and counties of his side.

Fortunately, Yelujing's blind optimism did not affect the front-line commanders. Xiao Haili, the new commander of Zhongjing Province, was still cautious about the retreat of Mutel's headquarters and the cancellation of the Lulongshan battalion of the Beiping Army. First, although Mutel's troops were in a dilemma because of the cut off of the grain route and the unfavorable attack on the county seat of the prefecture, they did not suffer any losses along the way, and the entire army still maintained the complete structure when it left Jinzhou, advanced and retreated in an orderly manner, and acted in a uniform manner. I am afraid that this retreat is more because the gains and losses of continuing to fight will not outweigh the losses, and it will not be possible to achieve such huge results as in the past. Moreover, when retreating, the formation was strict and orderly, and the various units alternately covered and retreated in echelons, which seemed to be very orderly, and it was far from the point of discouragement, low morale, and collapse of the ranks. As for the cancellation of the Lulongshan battalion, it can be regarded as a normal retreat operation carried out by the Beiping Army according to the established Jihua after the camp completed the mission of containing and confusing the Liao army before the camp, and a normal retreat operation under the condition that its own men and horses were threatened and suffered any losses and losses, obviously cannot be counted among the benefits brought by the success of the northern tactics of Zhongjing Province - the Lulongshan battalion did not seal off the surrounding area as tightly as before in the process of withdrawal. There is no deliberate camouflage in terms of numbers as before, so that the spies of the Khitan army can easily get a glimpse of its true face and figure out its true number.

Second, based on Xiao Haili's previous understanding of the Beiping Army through various channels, he believed that with the strong strength of the Beiping Army and the concept that it would want to put Daliao to death since the ninth year of the Ying calendar, after spending such a huge amount of manpower and material resources and creating such a huge momentum and influence, it would never be possible for Muttel's troops to return to the camp and stop because of the slightest setback, and be satisfied with the results of the invasion of the land of Run, Lai, Jin and other six states. This time, Muttel's retreat and the cancellation of the Lulongshan camp must have some conspiracy behind it.

However, although Haili wrote to the court several times and stated his interests to Yelujing, he hoped that the other party would not be blindly optimistic, but should be cautious everywhere, and never relax his vigilance against the Beiping army that deliberately showed weakness to himself. It's a pity that Yelujing did not accept Xiao Xuli's advice, but was still immersed in the "brilliant results" of "repelling" the Beiping army. It's just that the wish is beautiful, but the reality is cruel. The smile on Yelujing's face had not yet dissipated, and the news that the 15,000 troops of the Beiping Army had left Gubeikou and gone north and retreated to Jinzhou, and the news that Mutel's headquarters had turned around and rushed straight to Tokyo Road fell on his head like a heavy hammer.

Moreover, it is different from the past when the Beiping army went out to "fight the grass valley", and only plundered the property, grain and other materials of the Khitan people; It is different from Muttel, who marched eastward, to plunder local forts, harass the Khitan people, and create chaos in Tokyo Province. This time, the soldiers and horses of the so-called left road of the Northern Expedition from the ancient Beikou of the Beiping Army broke through a city, not only looted the property and grain of the Khitan people, and gave all their land to the people of the Han and other tribes, but also arrested all the Khitans in these cities, and escorted them back to the Great Wall in batches, like the soldiers who were captured in the Battle of Youyun, to serve as slaves and coolies. In other words, this time the Beiping army marched into Zhongjing Road, no longer just to hit the living Liliang of the Great Liao here, weaken the strength of the Great Liao, and hit the morale of the Great Liao army, but to completely drive the Khitan people out of Zhongjing Road, to exterminate the Khitan people, and to completely turn Zhongjing Road into the world of the Han people and other tribes that originally submitted to the feet of the Khitans.

Such a move by the Beiping Army made Ye Lujing, who had lost face due to the Beiping Army's sudden second expedition to the north, no longer able to sit still - in the environment where Daliao was repeatedly attacked by the Beiping Army, the situation was turbulent, the nobles and nobles in the clan were full of complaints, and political enemies were eyeing the throne, if he did not take action against the large number of people taken away by the clan, he was afraid that the throne would really be lost. On the one hand, Yelujing ignored Mutel's subordinates, who were rampaging on the Tokyo Road but would not have a realistic impact on the basis of his rule, and strictly ordered that in order to avoid repeating the mistakes of Yelu Tart, all his forces had been shrinking in the area of Dadingfu, and Xiao Haili, who did not dare to easily confront the Beiping army head-on, immediately led his troops south, and before the new reinforcements from the imperial court arrived, he blocked the Beiping Army's northern expedition to the left route army, which was violently killing Zezhou, and must not let it drive out all the Khitans in the city and along the way as he did in Bei'anzhou. On the other hand, he ordered the mobilization of all the troops he could from the area around Nakyo-do, and pulled out 20,000 horses from the few remaining Pimuro palace tent troops, and reluctantly cobbled together a reinforcement of about 70,000 men, and went south to reinforce Xiao Haili. He also ordered the soldiers and horses of the Southwest Road Recruitment Division to attack the Datong Mansion of the Beiping Army in order to attract the attention of the Beiping Army and disrupt its actions in Zhongjing Road.

Although through various channels, especially through the correspondence between the past and Yelu Tartlie, who had fought against the Beiping Army for many years, Xiao Haili already knew something about the Beiping Army, and knew very well that it was almost impossible to defeat or even resist the opponent's attack in a face-to-face confrontation with the 50,000 men and horses he had. However, in the face of the emperor's strict decree and the policy adopted by the Beiping Army to exterminate the Khitan people in the north this time, Xiao Haili had to lead the army south to fight a decisive battle with the Beiping Army on the left side of the Northern Expeditionary Army, just to show his loyalty to the emperor, just to show his reputation as a Khitan warrior and commander of the army, just to give the reinforcements who were not much stronger than his own soldiers and horses, and who were still not the opponents of the Beiping Army, to rush to buy a little time.