Of course, Zhuge Liang's confidence in Guan Yu was not unreasonable. After all, they had already made plans and started to lay out traps as soon as July and August when Liu Bei came to Luoyang for the eastern tour.

The total budget of Luoyang New City and Nanyang Canal has been added to more than one billion yuan to cope with the technical adjustment of "the stone required by Luoyang New City is mined on site from Yique Longmen, and the stone produced by the Tongbai Mountain Pass in Nanyang will be used to strengthen the urban defense of Kunyang and Ye County on site."

All the extra money is spent, so you have to make money back with the capital and the profit, right? What kind of people are Li Su and Zhuge Liang? Can they tolerate their investment loss?

Not to mention losing money, even if the return on investment is a little lower, it will not be acceptable.

Therefore, Cao Cao and Xiahou Yuan came to the fight in November. At first glance, there was no problem, but when they really started to bite the tough problem, they were shocked to find that Kunyang City had become an indestructible fortress, and they were simply kicked to the iron plate.

...

The first Cao army to arrive in Kunyang was Xiahou Yuan's army, and Cao Cao would have to arrive in three or four days.

Xiahou Yuan was in full swing. Relying on his large number of people, he ordered the troops to make preparations. He sent technical troops to build a catapult, a well railing, a chariot, and a wooden donkey to dig the city to prepare for a strong attack.

On the one hand, the army began to siege the city, build long trenches, camps, and corridors, and surrounded them to death. I thought that I would not delay both hands after a long time.

At the same time, Xiahou Yuan also roughly observed the terrain around the city and found that this Kunyang City was indeed different from other medium-sized and sturdy cities I remembered.

It seems that the city wall has become thicker, but not very tall. There are also bulging earth platforms built in the four corners of the city, which are much higher than the wall. This thing should be called "Jiu Tower", but the city before the Han Dynasty did not build a corner tower, so Xiahou Yuan could not name it.

In addition, the obstacles and facilities such as trenches, sheep and horse walls, and deer antlers resisting horses are indescribable.

There are also some secret killing weapons that Xiahou Yuan cannot see for the time being, such as the four gates have built the Neiwangcheng, but Xiahou Yuan has not yet climbed the tower, so he cannot see the existence of the Neiwangcheng.

Cao's army besieged ten levels of Kunyang City, and the camps were as prosperous as Wang Mang 180 years ago.

Kunyang City is located south of the Han River. Unlike Ye County, which is bordered by the Lishui River to the south, Kunyang has a higher terrain and the city is not directly bordered by rivers. It is difficult to divert water, so there is no moat.

The military water is still seven or eight miles away from the north city wall. Therefore, in history, when Wang Mang's army and Liu Xiu fought here, the Mang army had to be chased and oppressed by the Han army and squeezed into the military water. Only then did "the military water overflow, tens of thousands of drowning people were drowned, and they did not flow."

However, although it is not close to the river, there is no shortage of water in the city. Don’t worry about this, Xiahou Yuan will not use his brain in this direction.

The Chinese-style city was not thirsty for death by the water cut off. There were hundreds of wells in Kunyang City, and the groundwater was abundant nearby. Therefore, when Liu Xiu and Wang Mang's army fought, the people in the city could "take their homes and draw" under the suppression of the arrow rain on the well railing (drawing water with arrows on their backs)

Without a moat, Xiahou Yuan also saved the construction of trenches and bridges. He just needed to get some simple equipment and fill all the waterless dry ditches and traps.

On November 15th, Xiahou Yuan had not yet fully built the catapult car, but had just created other equipment.

Originally, he didn't want to launch a tentative attack so quickly, but on this day, he got the fast horse envoy sent by Bo Wang to Li Dian.

It is said that Xiahou Dun suffered a crushing defeat the afternoon before. Almost half of the 60,000 troops responsible for blocking Tongbai Mountain were lost by Xiahou Dun.

When Xiahou Yuan heard this, he complained, but he also knew that the news must be blocked and a fight was taking advantage of the morale.

He ordered the messenger not to make a statement. Xiahou Dun's defeat and heavy losses were enough for a few senior generals to know about it. He must not let ordinary soldiers of the siege know about it.

Then, before Cao Cao arrived, he launched the first wave of offensive without the help of the catapult.

Seven or eight ladder trucks, hundreds of ordinary light flight ladders, dozens of rushing cars, city-digging donkeys, and tens of thousands of infantrymen launched a tentative attack from the east and west directions.

Xiahou Yuan did not expect to break the city at once, so he filled all the trenches outside the city, smashed the sheep and horse walls, and cleared out the obstacles before the general attack.

After the attack began, Xiahou Yuan personally visited the battle to observe the enemy's defense.

The Cao army soldiers carried earthen bags like ants, followed heavy equipment to fill the trenches, and even mobilized and forced many local people and even prisoners in Yingchuan County to take on the most unskilled work.

After all, Yingchuan County was also an important source of chaos in the late Han Dynasty. When the Yellow Turbans were in trouble in the early years, the Yellow Turbans in Nanyang and the Yellow Turbans in Yingchuan were the most recurring. Whoever made these two counties have few lands and many people, and the population exploded and there were no fields to plant, could only be a thief.

There are too many prisoners in each county, and they can only be taken to work hard labor and reform, and they can't even organize military farms - because there are too many people and too few fields, and there is not enough land to plant. Now that we have to fight a siege, there are of course countless prisoners who can be brought up as cannon fodder.

Naturally, arrows fell like rain at the top of the city. Firepower began to be poured out after two or three hundred steps, scattering the Cao army and the cannon fodder prisoners who were charging, but they could not stop the Cao army's momentum.

Cao Cao was strict in his military administration, and Xiahou Yuan had strict military laws. Those who were afraid of fighting died, and those who became deserters or even surrendered to the enemy would even be in charge of their family. The soldiers of Cao's army were not so easy to be discouraged.

Historically, after the founding of the State of Cao Wei, many laws were put into place to replace defenses in other places to ensure the reliability of the troops and prevent the enemy from surrendering. Although it has not been implemented in the form of laws, its ideological prototype can be first seen in Xiahou Yuanzhi's army.

Xiahou Yuan sneered in his heart at first: "The guards in the city are too impatient. How could there be such a waste of arrows when defending the city? At least wait until the attacking soldiers approached within fifty steps before fifty steps before firing the arrows. What are you afraid of if there is a city wall?

It seems that he is not a famous general, and there is hope for Kunyang to take it. I don’t know who is defending the city, and no one answers the previous shouting and scolding formation."

The reason why Xiahou Yuan had this idea was of course because he didn't know that Guan Yu was in the city. Just as the war started, Guan Yu had no intention of revealing his identity. At least he had to wait until Cao Cao came to the city and suffered a lot, so Guan Yu planned to solve the mystery and shock the enemy.

Otherwise, I would have been afraid that the enemy would feel that he had been trapped at the beginning and would not dare to attack. Wouldn’t it be a waste of time?

Xiahou Yuan’s analysis of tactics is not wrong under normal circumstances, because the tactics of using firepower in the fire of the bow and crossbow during the war in the city are completely different from those in the field.

In field battles, because both sides are charging and fighting in handicaps, they have to fight in front of them, leaving a short window of time for long-range firepower output. The so-called "no three arrows at the end of the battle" refers to ordinary bows and arrows within a hundred steps. If you shoot three rounds, you have to fight in close combat.

In this case, you should cherish every second after the enemy enters the range. If you can output one more round, you don’t care whether you are wasting arrows. If you are too far, the hit rate is extremely low.

There is no time to seize the city. Even if the arrows are started before fifty steps, the hit rate will greatly increase. At the same time, there is no need to worry about falling into melee immediately. After the attacking side has to slowly climb up the high city wall after these fifty steps, the defensive side has a lot of time to output.

Xiahou Yuan suddenly realized that the defending generals "cannot fight against the city". Such a luxurious way of fighting would not require a siege of the city for a month or two, and the arrows in the city would definitely be exhausted.

However, as he watched, his confidence soon could not last.

As Cao's army filling the trenches became closer and closer, Xiahou Yuan found that the arrow density of the defenders was also increasing. Not only were people shooting arrows on the city wall, but there were a large number of crossbowmen behind the sheep and horse wall behind the trenches outside the city, and there were even those who arranged the crossbows behind the sheep and horse wall.

What was even more arrogant was that as Cao's army approached, the defenders actually opened the city gate, but there was a gate that could be lowered at any time. They obviously planned to contact the approaching crossbowman to return to the city at any time.

"The guard actually pressed the crossbowman in front of the city wall? Aren't he afraid that the crossbowman would fall into the ground to fight in close combat? He dared to open the city gate to meet them at any time? What if I rushed over and grabbed the door?"

Xiahou Yuan saw the adrenaline soaring, and he felt more and more that he was a fish-stealer on the other side, and his impulse was almost uncontrollable.

Fortunately, he was also a famous general who had fought an old war, so he finally settled down. At the same time, he took dozens of horses to patrol the city gate and walked to the front of the open city gate to look inside. Then he saw the existence of the inner city gate - there was a wall inside the open city gate, so he was not afraid of being taken away by accident.

Although he realized that the enemy did not have the danger of being captured by the city, Xiahou Yuan just couldn't understand the benefits of such deployment. At best, it was not profitable or harmless. Since there was no profit, why did the enemy have to make more trouble?

Fortunately, Guan Yu quickly revealed the mystery to him. The "profit" of such deployment was immediately reflected by the lives of thousands of Cao's soldiers and cannon fodder.

As the destruction progress accelerated, Xiahou Yuan finally discovered that the close-range crossbow shooting rate of the defenders was astonishingly high! The casualties of the Cao army in front were so fast that it was simply abnormal.

But Xiahou Yuan himself couldn't get too close to supervising the battle, and he was even a little confused, not sure what was going on.

...

In fact, Cao's army, who was destroying the fortifications in front of him, was undergoing purgatory-like baptism.

Especially the Han army's crossbows fired within fifty steps, killing people faster than cutting wheat. Although Cao's army had encountered crossbows many times before, the killing efficiency and hit rate of crossbows in the original experience could not be so high.

The tragic sounds were heard everywhere, and grassroots officers could not suppress them at all. Even the law of sitting could not shock the cannon fodder that fled backwards.

But they didn't know the principle, and they didn't even understand it.

At this moment, Guan Yu was also secretly observing the city, supervising the battle to defend the city, but he didn't have someone to use his banner.

Because Guan Yu was also curious about the effect of Zhuge Liang's newly built additional city defense facilities and newly deployed city defense tactics in the past few months.

The results of the actual trial at this moment undoubtedly made Guan Yu very satisfied. Moreover, in the months before the war, Zhuge Liang only told him about the ideas taught by the theory, but now it has been verified by actual combat, and the mystery of it suddenly became clear.

"Kong Ming's ability to master the math is really useful for the battle formation. It is just that the sheep and horse walls have become a form of gentle slopes and trenches. It actually has such an effect.

Kunyang City has a high terrain and no moat. It was originally a weakness. I didn’t expect that the hill-climbing terrain that is rising slowly the closer it is to the city wall. It has been slightly rectified and leveled, and the slope is modified. The effect of the powerful crossbow shooting directly to the enemy is so good."

It turned out that the ordinary ancient sheep and horse wall fortifications just made a low wall behind the moat, which was only about one person high. Before the enemy crossed the river, soldiers could be arranged to guard here and use bows and crossbows to shoot flatly to suppress the river surface.

Once the moat is broken, the traditional sheep and horse wall has to be abandoned. At the same time, the structure of the sheep and horse wall may also lead to being used by the siege party in turn. Once the siege troops fill the river and push it behind the sheep and horse wall, they can put their waists on the sheep and horse wall to cover the arrows and shoot at the top of the city.

Of course, because the sheep and horse wall is too short, and the main city wall is at least three times the height of the sheep and horse wall, the defenders on the main city wall still have the advantage of being condescending. The crossbowmen in the siege will still be shot by the condescending rain of arrows, and they can only sit and reload while sitting on the back of the sheep and horse wall while the arrow is loading.

However, because there is no moat in Kunyang City, Zhuge Liang, under the guidance of Li Su, actually built a gentle slope that gradually rises upwards, and does not have a wall that clearly highlights the ground.

The bunker that was originally for the guardian to hide was directly dug into a "half-ditch" - the reason why it is called a half-ditch is because the ditch has only a section facing the enemy side, and there is no section facing the side facing oneself, only a slope.

The depth toward the enemy side is just as smooth as the chest of the defender's crossbowmen. The defender can be like the rifle soldiers in the trench of modern war cats, only exposing their heads and necks on the ground, and shooting arrows on some arms. Most of the whole body is hidden underground.

Don't underestimate this design. The essence of this design is not only a better cover, but also the positioning of the siege party, which greatly increases the probability of the attacker being shot by a crossbow.

Because in normal field battles, if the altitude of the offense and defense sides are the same, the hit rate of the crossbow flat shooting is actually very high, and the hit rate of the shooting is low. Flat shooting is a line that swept a line, and the enemy is layered on the cross section, and those who fail to hit the front row may also be trapped in the back row. As long as there are enemies on the flight trajectory of the arrow, they can hit it.

The shooting hit rate is low because the shooting only hits a point, and the arrow descends from the sky. Not only do you need to aim left and right, but you also need to be accurate in front, back, up and down, which is equivalent to changing from a one-dimensional straight line aim to a two-dimensional planar projection aim, and the hit rate is reduced by an order of magnitude.

Unfortunately, there are very few opportunities for shooting in field battles. The so-called three arrows are only in front of the battle. Even the shooting at long distances is counted. The final shot may be only one chance.

Moreover, the field formation is thick, and if you shoot flat, you can only output the first row or the first two rows. In order to prevent the shot from hitting the comrades, the people behind can only shoot (the first row is kneeling and the second row is standing).

Or crossbows with particularly slow loading speeds are made into "three-stage fire of muskets" and take turns to shoot arrows and backward to load. This leads to poor output density.

Siege war can provide great convenience for the continuous output of long-range firepower. You have the opportunity to shoot dozens of rounds during the enemy's charge. However, cases of the city being broken are still everywhere. The damage of the siege warriors by the guarding bows and crossbows does not increase dozens of times more than that of field battles. This is actually a simple physical misunderstanding.

That is, although the defending soldiers have gained a high advantage and will not be approached, the defending soldiers have lost the opportunity to "block a line with a flat shooting" and can only shoot condescendingly in three-dimensional shooting.

The arrows shot down on the city walls all hit a single point, and they have to aim left and right and right, and then the up and down high and down high. If this point is not hidden, it will be shot in vain. It is precisely this physical principle that the defending party does not absolutely crush the siege party.

In fact, this problem has been solved with the popularization of engineering geometry in the Western world in the era of navigation.

The castle built by Westerners in the 16th century has been reduced in height, so long gentle slopes can be piled in front of the city wall and opposite the moat. The length of this slope is basically the same as the maximum range of the musket at that time.

After the siege soldiers walked to this slope, they no longer walked forward horizontally, but climbed the slope. The slope of the climbing slope always matched the rifle aiming line of the defenders on the city wall, so the massacre efficiency was doubled. (See the picture attached to the Easter Egg seal for a while)

It is equivalent to a three-dimensional shooting game that was originally fighting on the battlefield and eating chicken, but suddenly simplified to a two-dimensional plane horizontal level shooting game. Just aim at the left and right, and the right and left will be accurate, and the dimensions of the upper and lower are cancelled.

The massacre efficiency was absolutely excellent.

Of course, Zhuge Liang did not have so much manpower to carry out Western battalion-style construction. After all, the area of ​​the city in the east is much larger than that in the west. To build a "slope slope with the same length as the city wall and three hundred steps wide". Even if the height of the earth slope is only one person high, the amount of earthwork is already larger than the construction of the city wall itself.

Therefore, Zhuge Liang only controlled the length of this tangent slope to a width of fifty steps, which was equivalent to the range of the crossbow. In this way, the amount of soil work per unit wall length was reduced by more than 30 times (it was proportional to the cross-sectional area, the oblique edge was shortened to 1/6, and the cross-sectional area was reduced to 1/36.)

In addition, Zhuge Liang has participated in the construction of canals over the past year and has rich experience in managing soil work. When strengthening Kunyang City, he also assigned some manpower to do it.

At this moment, Xiahou Yuan's cannon fodder soldiers were so confused and fearful. They didn't know why they died so easily, and why all the Han crossbowmen on the opposite side became sharpshooters.

The hit rate of the crossbow was raised to a level similar to that of a machine gun, but the fire density was still far inferior to that of a machine gun - after all, one had to change the magazine if it hit ten rounds, and the other could hit hundreds of rounds before it was replaced.
To be continued...