The return cannon has been built, Sima Yi sent people to return to the camp quickly, so that people can transport the return cannon as quickly as possible, in order to save some time, Sima Yi also ordered some soldiers and horses to collect stones nearby.

Although the Wei army's return cannon was an imitation, it was equally heavy, and although the Longshan Road was wide, it was also difficult to transport it as a whole, so the return cannon was disassembled to make the carriage pull it.

The ancients made wooden utensils, rarely using nails, but playing mortise butt, easy to disassemble and transport, and the return cannon is like this.

Soon the return cannon was transported to the Longshan crossing, at this moment it was getting westerly, the sky was getting darker, Cao Pi in order to know whether Jieting City was a strong city, ordered a night battle.

Soon the assembly of the return cannon was completed, and dozens of return guns were erected on the road more than a mile wide at the Longshan crossing.

Cao Pi sat on his war horse, looking at the street pavilion city in front of him, and felt a little nervous in his heart.

According to reason, no matter what, it is impossible to build a strong city in more than a month, but looking at Liu Chan's confident appearance, he is obviously full of confidence in Jieting City.

If the return cannon really can't break through the defenses of Street Pavilion City, then what should it be?

Immediately, Cao Pi shook his head, feeling that his idea was a little ridiculous, the power of the return cannon was endless, even if the blue brick and stone slab wall could not last long under the continuous bombardment of the return artillery.

Even if the city built by Liu Chan is as hard as a blue brick and stone slab, as long as it is continuously bombarded, how long can it last?

Sima Yi walked to Cao Pi's side and arched his hand: "Your Majesty, the return cannon has been assembled, whether to attack or not!" ”

Cao Pi said coldly: "Give me an attack, I don't believe that Liu Chan can build an impregnable city in a month!" ”

"Attack me!" Hearing this, Sima Yi ordered loudly.

Suddenly, there was a stone rain in the sky, and dozens of hundred-pound boulders flew towards the head of the street pavilion city.

Liu Chan and the others had already gone down the city and dodged in the rear of the city, under the attack of Shi Yu, Liu Chan did not dare to easily attack his front, but in the same way, the Wei army did not dare to attack in this situation.

Rumble!

Rumble!

Rumble!

The boulder fell on the city head and smashed on the city wall, resounding with a huge rumbling sound, if the distance is closer, you can see that the boulder did not cause any damage to the city wall at all, at most the angular boulder rubbed against the wall, making some palm-sized potholes.

As for the kind of round stone without edges and corners, it is just to wipe off some cement ash, and it can be repaired with cement afterwards.

Liu Chan looked at the boulder falling on the top of the city under the city, and was stunned.

Chen Zhi saw that Liu Chan was distracted, thinking that Liu Chan was worried, and said with a smile: "Your Majesty don't worry, the last general has found someone to try, and the return cannon can't destroy the city wall." ”

Liu Chan smiled slightly when he heard this: "No, I am thinking that when the city is built, a roof should be made at the head of the city, so that not only can it be protected against arrows, but even if it is faced with the bombardment of the return artillery, it can also stay at the head of the city." ”

The principle of making a roof for the head of the city is the same as a building with two floors, only the pillars are thick enough, the roof is thick enough, and the return cannon is also difficult to damage.

The height is more than two meters, which is enough for people to pass, and it can not only increase the defense of the city in wartime, but also protect it from rain on weekdays.

The generals laughed dumbly when they heard this, originally they thought that Liu Chan was worried about the lack of defense of the city wall, but they didn't expect Liu Chan to be thinking about setting up a roof for the city wall.

The sky has not completely darkened, and the Wei army has already started a fire here, and Cao Pi looked towards the city wall by the light of the fire, hoping to find some big holes or cracks.

It's a pity that after searching for a long time, Cao Pi only found some palm-sized cement marks.

Cao Pi's face suddenly fell, this street pavilion city is really not afraid of returning to the gun!

Sima Yi saw that Cao Pi's face was wrong, and hurriedly said: "Your Majesty, if it is dark today, and this wall is gray and black, you can't see anything at all, it is better for Your Majesty to go back to the camp to rest first, and Weichen will continue to lead his troops to attack." ”

Cao Pi nodded and said, "Then I will be waiting for your good news tomorrow!" ”

Early the next morning, Cao Pi woke up early, summoned Jiang Ji, and asked, "It's been a night since Zhong Da led his troops to bombard Jieting City with Hui artillery, but is there any news?" ”

Jiang Ji's face was a little unnatural, and he couldn't speak.

Cao Pi asked, "What?" Didn't it work out overnight? ”

Jiang Ji hurriedly knelt on the ground: "Street Pavilion City is indestructible, Weichen and others are incompetent!" ”

"I don't believe it!" Cao Pi let out a loud shout, got up and left the camp, intending to go to Jieting City to see what was going on in person.

When Cao Pi came to Jieting City, the Wei army had already stopped bombardment, mainly because the stones had run out, and the soldiers were collecting stones in the mountains and forests.

The Han soldiers re-ascended to the top of the city, and when they heard that Cao Pi was coming, Liu Chan also climbed to the top of the city.

At this moment, the sky was already bright, Cao Pi looked towards the street pavilion city, and saw that the gray-black wall was full of potholes, but those potholes were not big, only the size of a palm, and they were not deep, the shallow ones were only scratches, and the deep ones were only one or two inches.

The reason why there are potholes is because the poured concrete city wall is uneven, because in later generations, the concrete will be poured with a vibrating machine to make the concrete stronger, and the cement slurry is evenly distributed.

The place where the stone was damaged was just unevenly distributed cement.

Although these potholes look terrifying, they are really a drop in the bucket compared to the city walls with a thickness of three or four zhang.

Cao Pi looked at the city wall of the street pavilion, his eyes were full of disbelief: "This is impossible! That's impossible! ”

Rammed earth city wall, a round of bombardment can be broken by returning artillery, blue brick and stone slab wall, a night of bombardment can also appear big holes or huge cracks, this Han army within a month, the shoddy city wall, why will there be nothing at all?

Now the Han army has built an impregnable city here, completely blocking the Wei army's road to Longyou, and if it can't take the city, it is equivalent to the west of Liupan Mountain, and there is no possibility of retaking this place.

Liu Chan climbed to the top of the city and looked at Cao Pi condescendingly, his eyesight was unmatched, although he was a hundred steps away, Liu Chan could vaguely see the expression on Cao Pi's face at the moment.

Aggrieved, helpless, hideous, guilty, and even fearful.

Liu Chan shouted to Cao Pi under the city: "Cao Zihuan, thank you for sending me so many stones, I can still use it to build the city." However, this bit of stone is far from enough, anyway, you have a lot of soldiers, so you will send more in the future, and you don't have to be afraid of damaging my city.

But I won't be able to thank you in the future, tomorrow I will go to Longyou and pacify Liangzhou, you can slowly collect stones for me to build a city here, I will tell you here to take care! ”

Cao Pi listened to Liu Chan's words, his face suddenly turned red, his throat swelled, and a mouthful of blood suddenly surged to his throat, almost spurting out.

Cao Pi knew that he couldn't let this mouthful of blood spurt out, so he hurriedly pursed his mouth, his face turned red, and then his throat surged again, but he swallowed this mouthful of blood into his stomach.

With so many soldiers and horses here watching, if Liu Chan vomits blood angrily, he will definitely not be able to hide it. At that time, if this matter is known, then he, the emperor of Great Wei, will lose his prestige, and the morale of the soldiers and horses will be greatly reduced.