Yelu Yilag did not move his troops in Enzhou, but he was in a hurry to besiege Zeng Zhilin and the Muters of Dadingfu. First, the reason why Zeng and Mu surrounded Dading and did not attack was that they hoped to use this as bait to implement the strategy of encirclement and reinforcement that the Beiping Army had used many times, annihilate the Khitan reinforcements in the movement, and defeat a little mobile Liliang of the Khitan Zuihou. Now that Yelu Yilag has not moved south, this trick will not work, and the goal of weakening the strength of the Khitan army as much as possible will not be achieved. Second, whether it was the Left Route Army of the Northern Expedition led by Zeng Zhilin or the cavalry unit of the Right Route Army of the Northern Expedition led by Mutel, the attack on Dadingfu this time used the policy of no grain routes and no logistical supply lines, so as to feed the war and obtain grain from the enemy. Both armies had limited food and grass to carry with them, and if the battle could not be resolved in a short time, the soldiers under their command would go hungry. The requisition of grain and grass stocks from those prefectures and counties conquered earlier may solve the urgent need for a while, but after all, these places have limited grain stocks, and they still have to keep some of the grain stocks to deal with emergencies, which can not be provided to the Beiping Army for use, and it is not enough to support the needs of the Beiping Army for a long-term siege war. Moreover, the safety of grain transportation from these states and counties is also a very big problem. After all, Jereilagah was cautious but not stupid. He may not dare to lead a large army to a decisive battle with the Beiping Army, but he will not hesitate to send a small force to attack the Beiping Army's grain route and cut off the opponent's logistics supply line. After all, his predecessor Xiao Haili followed the instructions of the Khitan court and forced back the cavalry troops of the Northern Expedition of the Beiping Army to the right route of the Northern Expedition with the strategy of fortifying the walls and clearing the wilderness. The biggest weakness of the Beiping Army's northern expedition -- the lack of grain and grass and the lack of supplies -- is obvious to all, and there is no reason why Yelu Yilage should not take advantage of this weakness. It can be said that Yelu Yilage's stagnation in Enzhou was, on the one hand, of course his intention to avoid the advance of the Beiping Army and not want to repeat the mistakes of his two predecessors and other colleagues who were defeated at the hands of the Beiping Army, and on the other hand, he must have taken advantage of the weakness of the Beiping Army's ineffective logistics in the Northern Expedition to consume his opponents.

It can be said that Zeng and Mu are now in a dilemma. On the one hand, if you want to annihilate the Khitan army, you can only implement a long-term siege strategy, wait for Yelu Yilag to resist the pressure of the Khitan Emperor to relieve the siege of Dading and have to go south, and then intercept it halfway to eliminate it. However, according to the current grain and grass reserves of the besieging Beiping army, it is impossible to support the Khitan reinforcements to the south. On the other hand, if we want to prevent the troops from falling into the predicament of lack of food or even no food, the only way to do this is to quickly conquer Dading City and replenish it with the food stored in the city. But in this way, the bait to attract Khitan reinforcements to the south did not exist. And with the cautious inference that Yelu Yi Lage is showing now, he is afraid that as soon as Dading City is broken here, he will have reason to give up the task of rescuing Dading City, and immediately lead the army to retreat north, so as to keep the Khitan army a little maneuverable.

As for temporarily ignoring Dading City and directly going north to find a decisive battle in Yelu Yilag, it is even more unrealistic. First, Yelu Yilage is now trying to avoid a face-to-face hard fight with the Beiping army, if he finds that there is an intention to go north to fight with him, I am afraid that he will retreat as soon as possible, and will not give the Beiping army a chance at all - with the mobility of the Khitan reinforcements, unless the Beiping army launches a war aimed at destroying the Khitan regime, otherwise the existing liliang and logistics situation of the northern expeditionary army under Dading City is basically not possible to catch up with the other party. Second, the Left Route Army of the Northern Expedition fought all the way, pursuing speed and maintaining strong enough combat effectiveness, so the states and counties conquered along the way did not divide their troops to guard, but handed over the relevant defense to their original Han army. At this time, if Dading Mansion is bypassed to seek a decisive battle with the Khitan reinforcements, the defenders of Dading City are likely to take the opportunity to send troops south to reoccupy the prefectures and counties that have been conquered by the Beiping army. In this way, not only will the Beiping Army need to spend time and energy to recapture these prefectures and counties, but there may also be a situation where the Khitan Army wantonly slaughters the Han people in these prefectures and counties in order to retaliate for the Beiping Army's captivity of the Khitans, and in order to punish the Han people who surrendered to the Beiping Army or helped the Beiping Army, which is absolutely unacceptable to the brothers of the crossing team.

However, in the face of the predicament, Zeng Zhilin was not discouraged. On the one hand, he sent the cavalry regiment of the 1st Division of the "Flying Dragon Army" to the south to persuade Nong, Wending, Yuzhou, and other prefectures and counties to collect grain, so as to ensure that the northern expeditionary army would not be short of grain in a short period of time. On the other hand, he also worked with Muttel to actively find countermeasures and find ways to break the current deadlock and complete the strategic goals of the northern expedition.

It's just that things are easier said than done, and after a few days, Zeng and Mu couldn't find a way to transfer Yelu Yilage, who was cowering in Enzhou City and couldn't hold out, out of the city. Seeing that half a day had passed, and there was still no progress on his side, Muttel couldn't help but feel depressed in his chest, he slapped the table fiercely, and said angrily: "I haven't thought of a way to do it for several days, and I am spending it under this Dading City, and this battle is really embarrassing." According to the younger brother, since the move of encircling the point to send reinforcements does not work, we might as well take Dading City in one go, use the treasury inventory in the city to replenish enough grain and grass, and then go directly north to find the decisive battle of Yelu Yi Lage. If he fights with us, if he retreats without a fight, then we will chase after him, and we will chase him wherever he goes. Not only that, but while we are chasing Yilage, we also have to kill all the Khitans we see along the way, killing one when we see one, killing one when we see two, and killing one of them cleanly. Kill until Yelu Jing, the dog emperor, can no longer sit still in his camp, and orders Yelu Yi Lage to fight a decisive battle with us. Hmph, I'm going to see if it's his Yelu Yi Lage who runs fast, or Lao Tzu's knife that is fast. ”

Zeng Zhilin waved his hand when he heard this, and said, "Thirty-fifth brother, don't be impatient. Not to mention how many Khitans will stay there along the way and wait for us to kill once we continue to go north. Let's just say that if the Khitans use the strategy of 'clearing the wilderness' some time ago, without calling on a large number of chariots and horses, our existing carrying capacity alone can support our army of 20,000 people in the 'hide and seek' game of 'hide and seek' for a long time in Zhongjing Road, Shangjing Road and the Khitan army, and Yelu Yi Lage. During this time, how sure are you that you will kill enough Khitans to force Yelu Jing to order Yelu Yilag to fight us in a decisive battle? Besides, we are a guest army, and we are led by the nose by the opponent in this unfamiliar place, and it is easy to lose the morale of the army after a long time, and it is easier to be caught by the opponent. ”

Speaking of this, Zeng Zhilin suddenly paused, and quickly caught the flash of inspiration in his mind. After thinking for a moment, he seemed to say something to Mutel, and seemed to be talking to himself: "Since I can't lure him south, why don't I do the opposite, and do what I do, so that I can lead his army back north, and then take him by surprise on the way of retreat." Such an effect should be similar to luring them south and encircling them to send reinforcements. Yes, that's it. ”

Thinking of this, Zeng Zhilin's forehead, which was originally gathered into a "Sichuan character", gradually stretched, and immediately issued a combat order to all departments of the Northern Expeditionary Army - on the fifteenth day of the eighth lunar month of the eighth year of Xiande, launch an attack on Dading City.