The Great Wall is, of course, a lock, and it is true for Zhuxia and other races. Numerous wars between farming nations and nomads have basically revolved around the Great Wall.

The Central Plains Dynasty was able to control the Great Wall, even if it did not have the strength to counterattack, it was able to resist the enemy forces coming from the grassland from the mountains of the Great Wall, protecting the counties in the rear from being ravaged by the Husbands. .

Thinking of the other way around, once the nomads break through the Great Wall, they can enter Sahuan in the counties and counties of the Central Plains Dynasty. Even if they are not going to grab some big cities, specifically those villages that are not protected by walls, they can still grab a lot of pots. Full.

　　Sangyu is against the demolition of the Great Wall. It is not that he does not want future generations to see this epic wonder, nor does he say that it may be built after it is demolished. It is very objective to point out that Han has no extra manpower at present.

　　 It must be said that the length of the contemporary Great Wall may be much longer than that of the Great Wall built in the Ming and Qing Dynasties. The east side starts from Liaodong and connects to Dunhuang. Although some areas in the middle are "blank", the Great Wall exists on the whole, making the Great Wall look like a giant dragon entrenched on the ground.

"Your Majesty, the Great Wall is mostly built on the mountain. If you want to dismantle it, it is not easy." Sang Yu didn't dare to fight Liu Yan directly and said logically: "The great man does not need to rely on the danger of the Great Wall, nor is it necessary for warning. Whatever it is."

　　 Liu Yan just thought about it that way. He really used a huge amount of manpower to demolish it. It's better to ignore it and let the Great Wall fall into disrepair with the passage of time.

Yu Yi, who has been shut up, is thinking about something else. The Han country is now gathering people into a county, and the colony is no longer building walls. There was a dynasty that adopted the same approach, and then waited for the country to become decadent, and the territory was everywhere. When incidents occurred, there were beacons everywhere, and because there was no city wall as a backing, the speed of the fall was faster than one place.

　　 The dynasty that Yu Yi thought of was the Qin Dynasty. After the first emperor completed the sweep of the Eight Wastes, he not only ordered the counties and counties to demolish the city walls, but also ordered the demolition of various gates.

　　 What kind of thought did the emperor first give such an administrative order? Because there is no relevant written record, the descendants can basically rely on guesswork. Most guesses are that the first emperor probably felt that there were walls in cities everywhere. In the event of a rebellion, the walls would become a barrier for the rebels. Then, the Qin army can fight well, and there is no need for a city wall to guard the city at all. A war is not based on a city wall, but an army composed of people.

In fact, if you look up historical books or geography, you will find that Xianyang is a metropolis without city walls. Because of the barrier of Hangu Pass in the counties and counties of Guanzhong, only some counties around Hangu Pass have walls. No city wall was actually built to the west or north.

　　 Then there is some reliable speculation as to why the First Emperor ordered the city walls to be demolished in various places. The cities in Guanzhong in the land of Longxing have no walls. Why do they have walls in places other than Guanzhong? Isn't it consistent with Guanzhong?

"The widow naturally knows that it is precisely because of the removal of various passes that Qin has no danger to defend, so that the emperor of the Han Dynasty can attack Xianyang. Xianyang also has no city defense as a support and encounters civil strife, Ziying has no choice but to lead hundreds of officials out of the tree-lined road. Naturally, Liu Yan ignored the Qin State and repaired several passes and city walls. Otherwise, Wu Guang also went straight to Guanzhong and was stopped in Xingyang, and Liu Bang didn’t need to go through the pass: “The capital of the country naturally needs to pass the pass. Prevent accidents."

　　 Sang Yu didn't directly mention the disadvantages of not having a barrier. He reminded him vaguely, seeing that Liu Yan was sensible, he naturally wouldn't say anything further.

The reason why Liu Yan believes that counties and counties do not need city walls is the Han country that has emerged from the ruins. Without the imminent threat, the manpower and material resources should be used first in the places where they are most needed, such as quickly repairing water conservancy and irrigation facilities. The county’s roads are also well maintained.

Another point is that Liu Yan is very aware of the current situation of Han. The population is currently in a state of rapid population decline. In fact, the number of people in each county is quite limited. The construction of the city wall will inevitably not be overhauled, and the population increase in the future will appear to be too small. The city wall will make the residential area inextensible.

The most important thing is that the firearms are already present, and they will develop as time goes by. The military role that the city wall can play is to decrease again and again. Waiting for the war to turn into artillery roars, and the soldiers also fight with guns. The city wall built by huge manpower and material resources was just a matter of heavy artillery bombardment.

　　 In the war of the firearms age, if you had the skill to build city walls, it is better to choose favorable terrain to build fortresses containing underground fortifications. At worst, you can also pull barbed wire and dig trenches. Isn't it more cost-effective than city walls?

　　 Speaking of firearms, Liu Yangang received a memorial from Chang'an, mentioning that the long-term research on the rifle has yielded results, and the physical objects and drawings were sent far away.

　　 The real thing Liu Yan saw didn't look like a rifle, so it was appropriate to call it a gun if he insisted on saying it.

　　 It was a big shot, reaching two meters in length, and the barrel occupies six to seven tenths. It is still in front-loading mode, it needs to be charged first and then the projectiles are put in. The triggering device uses flintlock, which directly skips the matchlock mode.

　　 "The caliber is 20 millimeters?" Of course Liu Yan can lift the big gun. He looked at the caliber and commented: "It's more like a gun..."

　　 Not to mention, the caliber of the gun is already large, and the caliber of the gun made in modern times is generally more than 15 mm. Even more exaggerated guns have a caliber of forty millimeters. It is better to call a gun than a gun by its name.

　　 "Charge." Liu Yan would not test fire by himself: "Try it with fire."

　　Naturally, there are sergeants who are busy. They use a fixed gunpowder bag. The process is to tear the gunpowder bag, put the gunpowder into the barrel, and then use the cleaning rod to push it forward. The next step is to load the projectiles. Someone takes the supporting bracket to support the front body of the barrel, and then one person lifts the back of the gun body.

　　 "Fire!"

　　 The military in charge of shooting pulled the trigger. He felt a strong thrust in an instant. Because of his inexperience, the man took a step backwards. Fortunately, he grabbed the gun body and didn't remove it.

　　 After the trigger was pulled, there was a loud "bang", and a puff of white smoke came out of the muzzle. Many of the people shuddered by the sudden movement.

Liu Yan has been looking at the arrow target placed in front...Uh, its responsibility has become the gun target. After the shot was fired, the target was safe, but the projectile penetrated the ground from a distance of 1,600 meters, which was hard to be seen by the naked eye. A piece of dust came out.

　　 "……"

　　 It was okay to see the target of the gun. Everyone looked at the sergeant who operated the shooting unanimously, making the sergeant's forehead sweat instantly.

　　 The range of the gun was very far. According to some records, the maximum range of the gun in the Qing Dynasty was 2280 meters. That is the range of the artillery, but the accuracy is almost no.

　　 Liu Yan has just watched it, the barrel is not a rifled pattern, it is destined to have no accuracy. He would not let the sergeant pull down and chop because the sergeant did not hit the target, just signalling to continue charging and shooting.

　　 Once again the preparation process, the sergeant was in charge of the shooting. This time he was much more nervous than the first time. He asked all the known gods in his mind to pull the trigger. His luck is very good, this time it can be regarded as not short.

　　 Gunshots rang again, and the gun target, which was placed about a hundred meters away, shattered.

That is, the target of the gun is broken. It is not only the projectile penetrating through it. The process of its fragmentation is extremely fast. The sawdust is shot horizontally, the hemp rope on it is directly broken, and the support frame is also smashed. He flew back several meters away.

　　 "Single-engine cannon." Liu Yan said a term that no one understood. He motioned: "Arrange a few more targets, and arrange them as far away as three miles away."

　　 I had a hit, and then seeing the target that was hit was directly smashed, everyone had a deeper understanding of this new weapon, and it was all because of its power.

　　 charged and fired repeatedly, and several sergeants in charge of shooting seemed to be getting better and smoother, waiting for the target placed three miles away to be hit by an unusually lucky one, and the test firing stopped.

　　 "Within two miles, the hit will inevitably break." Sang Yu stroked the gun target brought back from three miles away, and said happily: "Even three miles away, the hit has such a big hole."

　　 is a big hole, it should be about ten centimeters in diameter, and the wooden board used as the target is also full of cracks.

　　 "The farthest is up to three miles..." Yu Yi just asked the soldiers to explore more, and he really found the impact point: "It's farther than the range of our first-generation artillery!"

　　The first-generation artillery of the Han Dynasty was a six-pounder gun with a range of seven or eight hundred meters. The lethality of a solid projectile was only smashing, but there was no multiple penetration effect, and it would not kill or wound one shot at a range of ten meters.

　　 The current Han country has developed a variety of artillery, the largest being a 155mm naval gun with a range of up to six miles. The projectile aspect is no longer limited to solid bullets, and the incendiary bombs and incendiary bombs have also been studied. It is a pity that the artillery itself plus the gun mount is very heavy and it is not very convenient to transport.

　　 The most recent time in the Han country, except for Li Tan who just played artillery bombing the barracks, there will be no place for artillery to launch power again. There is a problem of transportation inconvenience. The army is also not installed by the Gyeonggi Guards or the Emperor's Guards.

"Widows have heard that Daqin or Persia also have firearms." Liu Yan did not recall from his own memory. It was a message sent back by Wang Meng, the envoy: "Daqin has ballistas, and the projectiles will explode when they fire, and there are also projectiles that burn on the ground. ."

　　If you count the time, Wang Meng should have reached the border of Persia, but he doesn't know where he is currently. He will go to Persia, the capital of the western capital of Thailand, and travel to other places. The next stop is to East Rome (Turkey).

　　 Rome attaches great importance to large-scale equipment. In addition to matching various large-scale military equipment, each legion also has a dedicated craftsman camp. They started to play with large military equipment after the conquering of Greece, and then they began to be out of control. Every time the Roman legions engaged in battle, the shadows of ballistas and catapults were bound to be seen, and the projectiles fired evolved from stones (bed crossbow arrows). To the projectile (fire oil bed crossbow arrow).

　　 Liu Yan still knows how the so-called explosive and flammable projectiles in Rome are about. In fact, they are products made by mixing petroleum with other materials.

　　 "Da Qin's ballista is the same as our artillery?!" Yu Yi rushed to the extreme surprise: "It was researched earlier than us!"

Liu Yan still needs to explain. Everyone was relieved to hear that it was a crossbow and a catapult. After hearing that the projectiles were researched with oil, they were curious to ask what the oil is, but naturally Liu Yan explained it again. What is oil.

　　The Romans and the Persians are not short of oil, and each has research in the field of oil use.

　　 The first country in Europe to use oil as a military weapon was Greece. At that time, Roman soldiers were burnt to coke (Greek fire) by Greek oil. After Rome defeated and occupied all of Greece, the Romans who were good at learning would naturally not let go of the use of oil. They also discovered that the homeland of Carthage (North Africa) produced oil, and the use of oil was more extensive.

　　 The Persians are relatively primitive in using oil. It is used for burning. It is usually placed in altars and pots, and then thrown to burn the enemy. They also have oil producing areas within their borders, or the kind that pops up by themselves without digging. The Arabs behind replaced the Persians to rule the land. The Arabs directly created the fireboat~lightnovelpub.net~ Because the Arabs and the Europas have always been superior in the confrontation at sea, there is also " They also cut off Europa’s connection with the East for more than two hundred years in the sea area named “Arabian Sea”.

　　 "It turned out to be a bed crossbow and a catapult, and it was also oil..." Sang Yu was still very proud: "We have always been in the lead."

　　 If you talk about gunpowder, it has actually appeared in the Spring and Autumn Period, but its power is so small that no one wants to study it specifically. Gunpowder has been a derivative of alchemy for a long time. Later, it was gradually transferred to entertainment (medicine puppets). It was only in the late Tang Dynasty that it was used for military purposes, but the power of the formula is still not very good. Sample.

　　 Liu Yan began to write afterwards. He asked to reduce the size on the basis of raising the gun, and at the same time asked about the research of the rifled carving.

It is inevitable that the Han army will use firearms on a large scale. The first large-scale use of firearms should be the navy. There are already twelve warships equipped with naval guns that have been launched for sea trials. I just don't know if I can catch up with the bombardment of Asan.

"Maybe five years..., ten years at the latest?" Liu Yan looked forward with deep anticipation: "Jieshi will have an army of rifles and artillery, and they will conquer from the east to the end of the west. ."

That day will inevitably come. The target of the battle will become Persia. Liu Yan will continue to promote scientific and technological research during his lifetime. Artillery and rifles have appeared one after another. As long as he continues to pay attention to it, the steam engine will be developed sooner or later. At that time, not only the Han army will sweep the land, but the navy will also cross the world.