When Tian Yu, the captain of Huwuwan, was still in Youzhou, he was as powerful as the governor of Youzhou Wang Xiong.
Tian Yu advocated being tough on the Hu people, while Wang Xiong advocated being gentle on the Hu people.
In the end, Cao Rui chose Wang Xiong not only because of their identities and backgrounds:
Tian Yu was just a surrendered general, and he was from a humble background and had followed Liu Bei.
But Wang Xiong is different. He was promoted by Cao Pi himself and was born into a Shandong clan.
More importantly, Cao Rui's choice of Wang Xiong can not only relieve the pressure on the Youzhou border, but also mobilize more manpower and material resources to go west to resist Ji Han.
Even as the relationship with the Hu people eases, you can also get war horses through the grasslands.
But everything has advantages, there must be disadvantages.
The years of peace and frequent exchanges with the Hu people have not only caused the relaxation of the military equipment in Youzhou, but also the gradual abandonment of frontier warnings such as Shuzhai.
"The Baoqiu Water is actually a road connecting Youzhou and the outer city. The caravans in Youzhou often take this route and transport salt and iron to Yishi City in the outer city."
"After Tian Yu left Youzhou, there were also tribes outside the frontier who drove the livestock on this road and went to Youzhou to sell."
"But it is mostly in autumn, now it is summer, and the river water is high, so few people pass by."
The old Zhu Wu pointed at Baoqiu Shui and explained to General Zhendong:
"Sir, don't look at the waterside and you can only ride together. When the autumn water is low, the water is exposed to the bottom of the water. This place can even be used for the brigade of cavalry to walk."
"When the villain was young, Wuhuan was still strong, so he often went south to rob the Han area."
Speaking of this, he looked carefully at the General.
General Zhendong's face was calm, his eyes fell on the road beside Baoqiu Shui that could only ride together, and said slowly:
"It is enough to be able to ride together, but only if it cannot be discovered."
The old Zhu Wu hurriedly said:
"Now the livestock on the grassland is the time to gain weight, and there will be no tribes coming here at this time."
After hearing the old Zhu Wu's words, General Zhendong did not speak, but his eyes were looking to the south.
"When will the caravans in Youzhou usually go out of the frontier?"
"Sir, the Han caravans go out of the frontier, and most of them buy and sell livestock and fur with tribes on the grassland, and they are basically in autumn."
Then there is no problem.
He asked someone to call Pei Xiu up and ordered:
"From now on, you not only have to record the sections of the road we have walked, but also have to draw the shape of the mountain. Do you know?"
Pei Xiu nodded:
"Show understands."
As a disciple of King Feng, you may not know anything else, but you must know how to calculate and draw.
It is rumored that this is the first knowledge that Mr. Feng taught since he came out of the mountain, and it is the open-door learning.
Pei Xiu himself has a very high talent and has a strong interest in map drawing. He has to join Feng Guiwang's sect, which is like a fish in water.
In recent years, many people have participated in the mapping of maps in the Han army.
After a few more years of experience, I will enter the North Korea and officially participate in the map surveying and mapping of the Han Dynasty.
The map is a confidentiality of the court. The more precise the map, the higher the level of the secret.
Not to mention military maps, if ordinary people dare to hide them privately, it is at least a start to make a mistake.
Pei Xiu now doesn’t need to worry about her future.
The only question is where you can go.
Being able to follow General Zhendong to make contributions to the war will undoubtedly write a strong mark on his resume.
——
Although the water volume of Baoqiu surged in summer and the roads by the water can only accommodate double riders in parallel, for the big men who had just passed through the swamp and the poison valley, this was already a smooth road.
If you don’t have to worry about being discovered, you don’t even have to send a scout out, just follow Bao Qiushui all the way south.
Seven days later, General Zhendong led 7,000 elite soldiers to a large bay quietly. This was not only closest to the ancient mouth of Yuyang, but also the last big bay for the army to hide.
Less than twenty miles south is Yuyang Gu Pass.
As soon as the army appears at the entrance of the Wan, it will be immediately discovered by the guards of Yuyang Gu Pass.
Yuyang Ancient Pass is built on the west bank of the Baoqiu River. The terrain in front of the pass is small and can accommodate at most a thousand people to attack the city.
The east bank of the Baoqiu River is cut through the mountains and cannot pass through.
There is a mountain on both sides of the pass.
If Guancheng is an iron lock, then the two mountains of east and west are two iron gates.
The three are integrated into one, forming an extremely solid Youzhou key.
As long as there are three or five thousand defenders in Guancheng and one or two thousand troops stationed in the east and west mountains, even tens of thousands of troops will probably be difficult to advance.
Of course, Guancheng is not without weaknesses.
That is to wait until the water volume of Baoqiu drops in autumn and reveals enough riverbeds. If the defenders of Guancheng do not block the riverbed in time, they will take advantage of the cavalry's advantages and fight for heavy casualties to pass quickly on the riverbed.
Then turn around and attack from front and back. As long as Youzhou fails to rescue in time, it is enough to capture the pass.
But this weakness is equivalent to not being the case for General Zhendong.
Because she couldn't wait until that time.
And she can't withstand such casualties.
Putting down the Qianli Mile Mile Mile, General Zhendong looked at Pei Xiu, who was also holding the Qianli Mile Mile Mile Mile Mile Mile Mile Mile Mile Mile Mile Mile Mile Mile Mile Mile Mile Mile Mile Mile Mile Mile Mile Mile Mile Mile Mile Mile Mile Mile Mile Mile Mile Mile Mile Mile Mile Mile Mile Mile Mile Mile Mile Mile Mile Mile Mile Mile Mile Mi
"how?
Pei Xiu estimated it in her heart and shook her head, "It's hard to say, I still need to go back and test it."
After gesture, he said, "Even if it can be done, the thief army may be able to move to the mountain in the west to hide..."
"You don't have to worry about the mountain, just pay attention to the checkpoint."
General Zhendong stared at Pei Xiu and said slowly:
"I urgently summon you to come here with the army just to solve the problem, not to ask you to ask questions."
"No matter what method you use, you must do this for me, otherwise you should know the consequences."
I don’t know if the weather was too hot or the pressure from General Zhendong was too great, Pei Xiu subconsciously let out a sweat:
"Students understand."
Then he raised the Qianli Mile Mile again and observed it carefully.
General Zhendong did not disturb him, but just looked at the mountain on the other side of Guancheng.
If you want to pass this pass successfully, in addition to winning the pass, you also need to take down the mountain on the west bank that depends on the pass.
As for the mountain on the east coast, it is not that important.
There is a Baoqiu Water separated by a river. If Guancheng is gone and the mountain on the west bank echoes, the military value of the mountain on the east bank will be greatly reduced.
There is a threat, but not a big threat.
After Pei Xiu finished observing, the few people quietly retreated down the mountain. The general of Zhendong along the way did not disturb Pei Xiu's thinking. He asked until he returned to the water bay where the army was stationed:
"What are your thoughts?"
Pei Xiu pondered for a moment and replied:
"It's not impossible. The outer city of the gate is about one meter away from the water surface. As long as the water level of the Baoqiu water can be raised by one meter, it will indeed spread to the city wall."
His eyes fell to the rushing Baoqiu Shui in front of him, and said thoughtfully:
"I have calculated the amount of water in Baoqiu these days. If you want to raise the water level by one meter, you only need to store water for two days, and it will not exceed three days at most."
"But there is a problem, that is, to find a water storage area of at least one mile in radius. Of course, this is the minimum requirement, preferably one and a half miles or even two miles."
General Zhendong pointed to the water bay where the army was located and asked:
"How is it here? It looks big enough."
Pei Xiu shook her head:
“Big is big enough, but the location is not right.”
He pointed to the downstream water turn, "The exit is too big, it is difficult to build a dam, and the temporary dam is not solid. If it takes too long, there is a risk of collapse."
"If you build a dam there, the foot of the mountain will not be high enough, and you need to increase it."
While saying that, he shook his head, "The project volume is too large, we don't have enough manpower. If we really want to start construction here, it is very easy to be discovered by thieves. It's inappropriate, inappropriate!"
General Zhendong frowned. She chose this place to camp, one for the purpose of concealing, and the other for the convenience of water attacks.
This place is not far from the gate. If you can really store water successfully, it is easy to catch the thief off guard.
Unexpectedly, Pei Xiu rejected it.
"This is the most suitable place. If it is not suitable, do you have any other choice?"
Pei Xiu took out a tart cloth bag from his arms and opened it carefully. It was a map he drew these days.
There are densely painted symbols that only he can understand.
"Please look here, General. Where did we pass by yesterday?" Pei Xiu pointed to a place on the map, probably because he was afraid that General Zhendong would not understand it, and then he deliberately circled it out with a pen:
"Here, just next to the Baoqiu Water, there is a pool of water, which is a low-lying land with a very dangerous terrain."
(i.e., the Heilongtan in later generations)
"Do you still remember the pool of water?"
General Zhendong thought about it and a dangerous place floated in his heart, and nodded: "I have an impression."
"Yes!" Pei Xiu said with a little excitement, "that place is big enough, and the outlet of the Baoqiu water is extremely narrow."
"Just cut off the Baoqiu water in this pond, block the outlet, and wait until the water is full, and finally open the dam to release the water."
"Storing water in a deep pool is much more convenient than here, and it saves a lot of manpower, at least much more than here."
"The downside is that it is about forty miles away from the pass, which is a bit far away."
General Zhendong slapped onto the map and said immediately:
"Forty miles, not too far, just right! Then store water here."
He looked at Pei Xiu and asked, "How much manpower is needed?"
"This," Pei Xiu scratched his head with a pen. "When the student passed by, he just took a brief look. As for how much manpower is needed and how high the dam needs to be built, he still has to go there to measure it before he can find out."
"Stay now!"
General Zhendong didn't wait for a moment and urged him.
Let Zhao Guang stay and lead the team to look back and go to find what Pei Xiu said about the pond water.
It took only more than an hour to travel around twenty miles and walk lightly.
The previous episode was just concerned about rushing, and the leader passed by quickly without having time to take a closer look.
When I returned to Tanshui to observe, the first thought of General Zhendong was:
This is really a great place to set up an ambush!
The pool water is embedded in the folds of the main vein of Yanshan Mountain, shaped like a gap nipped out of the fangs of a giant beast.
Two rock peaks face east and west, and the rock walls are covered with longitudinal gullies, like trenches plowed out by the gods with their fingernails.
The Baoqiu River was tightened by the mountains here, and the river channel, which was originally thirty meters wide, suddenly shrank to five meters.
The river roared like thunder as it squeezed across the pass. The water mist that rose did not dissipate for years, condensed into blue-black moss on the rock walls. From a distance, it looked like the old scales of a giant dragon faded away.
There is a layer of strange dark green floating on the surface of the pond all year round. When the sunlight is direct at noon, the water surface will see golden and green waves, just like a dragon's eyes opening and closing.
Thousand-year-old cypresses grow in the cracks of the rock. The trunks are twisted like spasms, but the crowns are tilted southwards. This is a unique "flag tree" in Yanshan, which is caused by the north wind outside the border for many years.
The shallows were piled with animal bones rushing down from the upstream, soaked in grayish white.
Once General Zhendong mentioned it, he could remember this place because the terrain here was too unique.
Even if she passed by in a hurry, she left an impression on her.
"General, look!"
Pei Xiu raised his eyes to observe the surroundings and suddenly pointed to a certain place.
Following Pei Xiu's pointing, I saw that the terrain on the north side of the Tankou was somewhat incompatible with the surrounding area, as if it was done by artificial means.
When they approached, the soldiers asked the sergeant to clean up the weeds, and half of the rammed earth dam revealed their true colors.
"General, it turns out that a predecessor had built a dam here for a long time!"
Standing in front of the broken dam, Pei Xiu touched the rammed earth that was still solid. While excited, she couldn't help but wonder:
"Yes, yes, there are indeed people building dams here, but for some reason they were destroyed. But it doesn't seem like it was washed away by water..."
General Zhendong was also surprised that the dam ruins appeared here. She looked at the destroyed place and looked clear:
"This is being destroyed."
Pei Xiu was shocked:
"Since ancient times, water control has been a great merit. I only heard of promoting water conservancy, but I have never heard of destroying water conservancy. Who is so bold?"
"How do I know?" General Zhendong was a little impatient. "Youzhou must be able to build a dam here. You really want to know that after you capture Youzhou, you will go and check it out."
However, in order not to dampen Pei Xiu's enthusiasm, she still explained it more:
"You have said that water control is a great merit. If Youzhou built this dam, it will naturally not be destroyed for no reason. The most likely thing is that the Hu people went south to rob, thinking that the dam was in trouble, so they were destroyed."
If such a good place to set up an ambush, thousands of people would lose tens of thousands of people if they could make good use of the weirs.
Therefore, the Hu people destroyed the dam, which is not considered a nonsense.
(According to later generations, this was built by Zhang Kan, the prefect of Yuyang of the Later Han Dynasty, when the land was stationed, and it was later destroyed by the Xianbei to go south and robbed.)
Seeing that General Zhendong was a little impatient, Pei Xiu remembered the purpose of his trip and did not dare to say more.
After a round and observation, I returned to the remains of the dam:
"Since my predecessors built a dam here, why should we pay more attention? And we can also use this half of the dam to save a little more trouble."
After saying that, he took out the tools on the spot and began to measure the dam. There were also students from the academy in the army who could help Pei Xiu.
After the measurement was completed, there was another intense calculation.
When the results came out, it was already night.
"General, with this half of the dam, it originally took three days to build the dam, but now it only takes two days."
Pei Xiu held a piece of paper in his hand and handed it to General Zhendong, "Add to store water, it only takes five days at most."
Anyway, it is a temporary dam, so there is no need to think about too much.
Just simply calculate the project volume and it's almost done.
General Zhendong glanced at the paper and saw that there were numbers on it, and some of them were unique formulas of Alang Master.
She didn't reach out to take it, just asked:
“How many people are needed?”
"It takes about one thousand people to build a dam, and if there are more, it can't be squeezed. In addition, it takes two thousand people to log and weave baskets to install sand and stone."
"Total three thousand?"
"right."
"Six thousand people are divided into two groups of people and take turns to carry out. I want you to build this weir as quickly as possible."
As for the remaining one thousand people, they will scatter out to monitor the possible enemy situations.
Anyway, it is nearly one day away from the gate, so don’t worry too much about being discovered by the thieves at the gate.
"Remember, the more water you store, the better!"
"Students understand."
It is only a five-meter-long mountain pass with six thousand people, which is more than enough.
Plus, the college-born generals and schools help.
It makes Pei Xiu confident.
He is really familiar with civil engineering.
Not only him, but many students from college are also familiar with him.
Mr. Sir is right, civil engineering knowledge is of great use, whether it is governing the people or in the military!