Bai Jinguang's description was roughly the same as what Kuhehan said, and after listening to it, Zhao Junsheng asked Kuhehan: "I plan to build a city here to prevent Princess Tuzhen and her people from moving south again and reoccupying the Mobei grassland after we leave, what do you think?" ”

This question is really difficult to answer for Kuhehan, he is a Rouran person, although he surrendered and surrendered to the Qianchao, but he has always been a Rouran person, this point cannot be changed, now Zhao Junsheng actually asked him if he could build a city here, if he said that he could not build a city here, he would be accused of not being sincere and obedient; If he said that he was in favor of building a city here, and he was suspected of flattery, it was really difficult to deal with.

Hu Hehan thought for a while and saluted and said: "Your Majesty, please forgive the minister, just building a city is not able to hold Mobei, once Princess Tuzhen and they are relieved, they can completely wave their troops south to cut off the connection between the city and the imperial court here, without supplies and reinforcements, the garrison will not last long!" If you want to defend Mobei and prevent other tribes from getting involved in Mobei, you can only move a large number of tribesmen and deal with the covetousness of other tribes with the method of all people! ”

Zhao Junsheng, Dongfang Chen and the others nodded secretly, Hu Hehan's words were still very pertinent, and they did not avoid this question.

Li Song said at this time: "Your Majesty, this time we didn't bring tools, and we didn't have craftsmen, I'm afraid that we won't be able to dig the mountain and build the city, and I'm afraid we will have to wait until the next time to build the city!" ”

Zhao Junsheng shook his head and said: "As soon as we leave, those Rouran people who moved north will definitely go and return, or other tribes will occupy here, so even a few months of power blank period can't be there!" ”

At dinner, in order to celebrate the meeting with Bai Jinguang's men and horses, he once again slaughtered cattle and sheep, so that the soldiers of the whole army had a full meal.

In the tent, Zhao Junsheng and the generals and ministers of the army drank wine and ate meat while talking.

He said, "I plan to leave a general with 5,000 men and horses to guard here for three months!" Tomorrow, I will send 800 miles of expedited horses back to Chang'an, and order Fu Zhan to lead 5,000 cavalry, 3,000 foot soldiers, and 2,000 people to rush with a large amount of grain, grass, tools, and other baggage, and rush to change the guard in three months at the latest! I wonder which general would like to stay and guard for three months? ”

This is a chore, don't look at it as only three months, once the main army withdraws, there will be 5,000 men and horses left here, which can be described as a lone army, which may be attacked by the barbarians of the Mobei at any time, including Rouran.

The risk of this lone army staying here is very high, why? Because it is a strange environment, people are always cautious in an unfamiliar environment, very honest, and dare not be presumptuous; In his own home and hometown, he is always very presumptuous, even rampant. Just like a person who has never been far away to study or work in other places, if he is unfamiliar with the place and has no relatives, he will definitely feel very panicked, lonely and helpless, even if he just meets a fellow countryman, he can feel the warmth, although they are two different things, but the truth is the same!

Under such circumstances, the lieutenant generals and colonels of the army are restrained, and they are not as calm as they should be, and they are worried about making mistakes, and sometimes the more they worry about making mistakes, the easier it is to make mistakes.

The generals were all thinking about whether to take the initiative to ask Ying to stay, Bai Jinguang, who had the highest qualifications, and the lieutenants were silent when they saw that the generals were silent, worried that the emperor would not be able to come to the stage, and were about to stand up and ask for their lives, Yang Lie was the fastest to take a step towards them: "Your Majesty, please lead the army to stay and guard the northern frontier!" ”

Zhao Junsheng showed a smile on his face and praised: "General Yang understands righteousness, is loyal and courageous, and I am very relieved!" I named you the general of Ningbei, and gave you 5,000 soldiers, 2,000 horses, 5,000 cattle, 20,000 sheep, 200,000 catties of grain, 300,000 arrows, and a number of other baggage. You only need to defend for three months, and within three months, Fu Zhan will lead an army to replace you, and then you can return to the court, and I will send troops to meet you at the border! ”

Yang Lie bowed down on one knee: "The minister receives the order!" ”

The army continued to rest for two days, and then Zhao Junsheng led the army to the division, and Yang Lie returned with 5,000 soldiers and horses, and Zhao Junsheng left him the promised livestock and baggage.

After Zhao Junsheng led the army, Yang Lie personally led the troops to replan the camp, using some tools such as swords, spears and shields to cut down trees around the camp to build a camp, arrange traps around the camp, build stables, cattle sheds and sheepfolds, send people to graze cattle full-time, and build a number of beacon towers on the high mountains near the camp for warning.

The role of these 5,000 soldiers and horses is not only to garrison the camps in square inches, but also to carry out a strong deterrent to the barbarians of various tribes who covet the grasslands of Mobei.

Therefore, Yang Lie sent cavalry in units to parade around to fight against all the barbarians who tried to graze and live in Mobei, and the cavalry on the patrol had to patrol as far as three hundred miles away, and it would take five or six days to go back and forth.

The parade adopts a rotation system, and the men and horses should rest in the camp for several days after the parade mission, and the permanent strength in the general camp is as many as 3,000 people, divided into three thousand teams, and the cavalry who go out to parade can be reinforced at any time to cope with the sudden situation.

After taking the squad from the camp on the south bank of the Beihai Sea, Zhao Junsheng's army returned to the Mutuo camp ten days later.

"Hey, what's wrong with this Mutuo camp? Your Majesty, look? The lieutenant who was following Zhao Junsheng pointed ahead and said to Zhao Junsheng.

Zhao Junsheng looked around and found that a large fortress had been erected on a hill next to the Mutuo camp, this fortress was made of stones, composed of a dozen fortresses of various sizes, and the highest fortress was erected on the top of the mountain, towering high.

Zhao Junsheng was impressed by Chang Kun and the others who stayed here, and it was only twenty days since he led the army to leave, and Chang Kun and others organized people to build such a large fortress here.

Chang Kun and the generals and officials who stayed behind rode up to meet him.

"Greetings to Your Majesty!"

Zhao Junsheng smiled: "You are indeed welcome, look at this fortress, what's going on?" To my surprise, it only took me 20 days to build! ”

Chang Kun said: "This idea was suggested by Liang Chengdong, an officer with the army! Liang Chengdong, come out! ”

An official immediately stepped forward to salute Zhao Junsheng: "The minister has seen Your Majesty!" ”

Zhao Junsheng nodded and asked, "Why do you suggest casting a fortress here?" ”

"Back to Your Majesty, since the minister came here with His Majesty, he accidentally found that this mountain was full of scattered stones that could be easily mined, and remembered that His Majesty said that if he wanted to defend Mobei, he would build a garrison in Mobei and recruit a large number of people to come to graze, so he had an idea. And this location is very suitable for building a city, the materials are ready-made, and there is a large number of ready-made labor, and here is the intermediate node between the old Khan's court and the North Sea, where the city can be built to reinforce both the Khan's court and the North Sea, located in the upper reaches of the confluence between the two major rivers, the geographical location is extremely important! If you hold this place, you can block the enemy coming from the west to the east, and you can also easily cut off the return route of the enemy army who killed the Khan's court from the north! ”

After listening to this, Zhao Junsheng couldn't help but look at this Liang Chengdong with admiration, this civilian official is very good at seizing the opportunity, and his military vision is very comparable.

Regarding the matter of building a city here, Zhao Junsheng only talked to Dongfang Chen, Chang Kun, Wei Juan, and other three people, but he didn't expect Liang Chengdong to also see the importance of this location, and also found that the hill next to it was suitable for building a city, so he suggested that Chang Kun take local materials and use the labor of those obedient Rouran people.

Thousands of Rouran troops and more than 10,000 Rouran old and weak, plus nearly 20,000 cadres and soldiers took local materials, and it only took more than 20 days to turn a barren mountain into a large fortress.

Wei Jun smiled and said to Zhao Junsheng: "Your Majesty, among the ministers, this Lord Liang is a talented person, if he goes through some training, he can be of great use!" ”

Zhao Junsheng looked at it and waved his hand: "Let's go over and have a look, let's go!" ”

The army and horses went to the camp to rest first, Zhao Junsheng and his party came to the fortification, accompanied by Chang Kun and Liang Chengdong, Zhao Junsheng and others visited the fortress that was still being built.

Zhao Junsheng came to the top of the fortress at the top of the mountain, and looked down, almost unobstructed within a radius of more than twenty miles, and could see every move of the enemy army far away.

Zhao Junsheng asked, "Whose idea was the shape and structure of this fortress?" ”

Liang Chengdong replied: "Back to Your Majesty, it was suggested by the minister to General Liang, so that you can make full use of the terrain and stones on the mountain!" ”

"Yes, yes, very well thought out, but no matter how I look at it, I think this fortress has a bit of a Western castle style!"

Liang Chengdong was surprised: "Your Majesty also understands Western architecture?" ”

"I don't understand, I've just seen similar pictures in the classics!"

Liang Chengdong said: "When Prince Persian Belus went to Chang'an, the minister was fortunate to get acquainted with him, and once the minister went to visit him and found that he brought many books from the West, some of which were dedicated to introducing the architectural style of the Western Roman Empire. ”

Zhao Junsheng thought for a while and asked, "Liang Chengdong, if I let you stay and continue to preside over the construction of this castle, would you be willing?" ”

Liang Chengdong immediately saluted and said: "The minister has this intention, if it is not halfway, the minister feels regretful!" ”

"Well, I ordered you to stay here and preside over the construction of this castle, but you won't have so much labor available in the future, I will take all these Rouran troops and the obedient Rouran tribe with me, and only some of the soldiers stationed here can be mobilized!"

"Command!"

After resting for two days, the army left 2,000 men to garrison and continue to improve the construction of the castle, and officially returned to the court.

After crossing the Zhiju River, the army marched south along the direction of Shishui for two days, then turned southeast, and arrived at the Khan's Court two days later.

There are 1,000 people left behind by the Khan's court, and the former lively Rouran Khan's court is gone, and there is only a depression at this time.

The soldiers of the Northern Expedition rested for another day in the Khan's Court, and continued their journey south the next day.

The army crossed the Dome Ridge and followed the water of the garden all the way to the south.

After arriving in Daze, Zhao Junsheng sent Chang Kun to lead 5,000 soldiers and horses to escort the Rouran troops and the Rouran troops who returned to Shun to the western foot of Jinwei Mountain to be handed over to Su Ji for placement, and those troops were to be escorted to Pu Zhihai, and after completing the task, Chang Kun's army would return to Chang'an through the Western Regions.

After the army was divided into two routes, Zhao Junsheng led the army from Daze to march in the direction of Bigan City through Junji Mountain and Jiluo Mountain.

A few days later, the army arrived at Bigan and rested for two days, then set out for the south again, arriving at Jilusai five days later.