The grain transport ships on the river are all flat-bottomed boats, and they do not have any offensive facilities. Except for soldiers standing on the ship and shooting randomly, it is difficult to have too much attack power. Moreover, the ships are swaying and the ships are relatively scattered. Even if they use dense rain of arrows to attack the enemy, their lethality is much weaker.

It is better to have a wide river like the Yellow River and the Yangtze River, but if it is a river on the plain, the widest river is only a hundred steps, and the narrower place is only twenty or thirty steps. Once the enemy occupies both sides of the river, it will be a disaster for the fleet.

Few people will fight with more than a thousand ships, which is almost brainless and deadly. Not to mention Cao Hong, Cao Cao will not think about this, but Dong Hu has the advantage of cavalry, so he can set up ten thousand cavalry on both sides of the strait to escort the fleet.

It is too dangerous for more than a thousand ships to enter the Jishui River. Once others set fire, it would be a disaster. Logically speaking, even if there are cavalry escorts on both sides of the Taiwan Strait, Dong Hu should not take such danger, but he needs to fight a shocking offensive and defensive battle.

April is approaching, and in May he must end the war in Jiyin and Shanyang County. These two counties avoided the rampant million Yellow Turban Army last year. There were winter wheat planted last year in the fields. He had to ensure that the war ended before the summer harvest. Cao Cao clearly stood by the city wall. If he wanted to take down the battlefield, he had to use heavy siege equipment.

It was too late to build temporary siege equipment, but the ship solved this problem and could directly move heavy giant crossbows and catapults from the arsenal.

More than a thousand large and small ships directly killed from Luoyang were within the area controlled by Dong Hu, and Cao Hong could not have heard the news. When he learned about it, countless ships had already reached the city. In addition to fighting to kill some spies for help, all 30,000 Cao troops were blocked in the city.

Dong Hu did not give Cao Hong any preparation time, and he attacked hard as soon as he came up. First, 20,000 cavalry surrounded the city and shot the guards at the top of the city. Cao Hong had seen this kind of fighting style in Chenliu, and immediately ordered the soldiers to hide under the female wall.

Seeing that the four cavalry camps had no effect in shooting back and forth, Dong Hu immediately stopped the attack.

"Tell Jiangzuoying that in one hour, fifteen trenchers must fire."

"promise!"

Dong Huyuan looked at the city wall and saw that Cao's army did not have too much disturbance. He secretly praised Cao Cao for growing up too fast, and it took only how long he had stopped the morale of the Qingzhou army.

After the military order was issued, the first attempted attack ended like this. Dong Hu turned around and returned to the temporary central army tent. He wanted to listen to the reports of the generals of the Four Cavalry Battalions, and roughly judged the defense strength of each city gate from the reactions of the soldiers at each city head, and chose the main attack direction.

Dong Hu temporarily stopped the attack, but Cao Hong, who was standing at the top of the city, was even more nervous, especially seeing countless craftsmen assembling huge trenchers...

"General..."

A general hurriedly climbed up to the city.

"The last general has already observed it. Except for those outside the southern city... there are those, there are no other gates in each city."

Hearing such words, Cao Hong felt a little relieved and looked at the armored general with a serious look.

"Then Dong Hu is very comparable. Each city gate must not relax its vigilance. In addition, recruit young and strong men to climb to the top of the city immediately! The thieves come and everyone will fight with the thieves to the end!"

"promise!"

Cao Hong looked serious, but his mind was messy... Time passed little by little, and Cao Hong stood at the top of the city with his sword, silently watching the gradual formation of stone catapults several feet tall one or two hundred steps away, and looked at countless armored iron cavalry...

"Boom...boom..."

The war drum of the sky suddenly rang without warning, and the big hand pressing the sharp sword suddenly tightened. Cao Hong looked at the disturbed and disturbed Min Zhuang and soldiers on the city.

"Everyone knows that the Liangzhou thief is cruel, and now the Japanese general and you and others live and die together!"

"If there is a turmoil in the army, behead you!"

With a "clang", Cao Hong's sword was unsheathed.

"Play the drum to cheer—"

As Cao Hong drew his sword and roared, war drums were rippling on the top of the city. Just as the morale of the army gradually stabilized, more than ten black shadows outside the city rushed towards him.

"General, be careful..."

While a man shouted out his words, he threw Cao Hong to the ground, without waiting for Cao Hong to be furious...

"Boom boom boom..."

The loud noise exploded in his ears for more than ten years. A man was torn into two halves by a big stone on his head, and half of the city gate tower was smashed...

"This...this..."

Cao Hong looked at this scene a little dazed, and then slapped him twice in his mouth, making his followers look horrified.

"The thief has only fifteen thunder cannons. Even if I let him smash it, the thief can't do anything to me-"

Just when Cao Hong was furious, someone suddenly screamed.

"fire--"

"The thief set fire-"

"boom!"

A ball of fire hit the city gate tower that collapsed halfway, and more than ten balls of fire went over the city and smashed into the city. This time, it was obviously thrown farther than the previous stone ball.

Regardless of the danger, Cao Hong hurried to the other wall, and saw dozens of fires lit up in the city.

"Be careful, General!"

"The thief threw the fireball again-"

This time no one threw Cao Hong down. Cao Hong instinctively lowered his body, and more than ten burning fireballs flew into the city. Cao Hong saw clearly that a ball of fireballs hit a house in the city, like a spark, and the splashed flames instantly swallowed the entire courtyard...

The first wave is the solid stone ball that tests the distance, the second wave, the third wave... are all hollow stone balls, with four hollow stone balls. There is a pot of fuel inside the stone ball. The outside is tied with hemp rope. Because the weight is lighter than the solid stone ball, the projection distance is also farther. Once the hollow stone ball hits heavily on the wall and the ground, it will immediately burst, creating a fire scene of ten meters in radius.

The weight of the wooden box at the tail end of the counterweight catapult is fixed, and the length of the casting rod is fixed. That is to say, the force projected is unchanged. The only thing that can affect the projection distance is the weight of the projectile and the length of the casting belt.

The heavier the projectile, the lower the height of the vertex of the projectile, the closer the projection distance, and the length of the casting belt wrapped in the projectile also determines the projection distance.

The principle of the counterweight catapult is the same as that of a person holding a catapult pole. He throws the stone out, which is different from the principle of a thunderbolt chariot. The reason why the thunderbolt chariot sounds like a thunderbolt is that the wooden pole that throws the stone will hit the horizontal wooden pole of the catapult chariot, and then it makes a "pop".

The counterweight catapult uses potential energy, while the thunderbolt cannon is torque force or pull-bow elasticity. Both are thunderbolts, and the principles are different. If it is a siege, the giant counterweight catapult is the sharpest. If it is used on a warship, the thunderbolt cannon is more suitable.

As the Craftsman Camp replaced different stone-cat belts, the range of the "incendiary bomb" was also increasing, and the fire gradually spread. In just one or two hours, the fire almost burned half of the city.

Ninety-nine percent of the houses in this era are wooden houses and thatched huts. Rich and noble families must live in the center of the city, while ninety-nine percent of the houses near the city wall are ordinary people, basically all of them are messy thatched huts. Such houses are the most likely to be ignited by fires.

Whose house is not panicked when it catches fire? Use the length of the catapult belt to adjust the range of the catapult, gradually transfer firepower to the enemy's depth, further aggravate the fire in the city.

Water and fire are ruthless. Once the fire burns, even if there are yards surrounded by earth walls in the city, Mars several meters high will fall on nearby houses. Under the scorching heat, Mars will fall on other thatched roofs and will immediately burn quickly.

Dong Hu stood outside the city to observe and judged the chaos in the city according to the rolling smoke...

"I ordered the craftsman to build a camp, and replace the incendiary bomb with solid bombs, and hit the city wall hard, and concentrate on a corner of the southeast of the city wall!"

"Then the order Sun Niu, Hu San, Li Jue and Guo Si will attack Xicheng for an hour. If the attack is not allowed to take down the Xicheng Gate for an hour, the attack will be temporarily suspended."

"The order to Dong Fu and Dong Fang harass Beicheng and Dongcheng."

"The message was made to alert Dong Gu to the direction of Dingtao County. Once Cao Cao was found to come to help, he would immediately send a message."

"Sent Zhang Liao to be alert to Cao Hong suddenly attacking from the south city and destroying the catapult..."

"Sentence..."

...

After observing the fire in the city for a while, Dong Hu secretly estimated that the people in the city were putting out fires, and the chaos of the people would definitely affect the morale of the Cao army guarding the city. He decided to let Sun Niu and Hu San launch a strong attack in the west city. As for the East City, the North City, and the South City were just to attract the firepower cover of the soldiers guarding the city.

Just as he was about to go to the West City to take a look, Xiao Dongbai, wearing a mask, suddenly grabbed his clothes.

"Dad, can't we use stones to smash their city gates? Why do we need people to smash them there? There is no city gate there and there is a lot of water!"

Seeing Xiao Dong Bai pointing to the southeast corner, Dong Hu couldn't help but smile, bent his knees and squatted down, pointed his hand at the city gate, and said with a smile: "Based on the steps taken by the soldiers on the city gate several times, you can roughly determine that the city wall is two meters wide. If you look at the city gate tower at the city gate, you should know that the city gate is the most solid place."

"The strong city wall is secondly. If we want to break into the city gate, the enemy will definitely want to drive us out. So, the city gate hole is the most dangerous place for siege."

"The enemy is worried that we will hit the door directly, so we dug a moat outside the city wall. When you fill the moat with soil, they will block the city gate with sacks filled with sand and soil in the city. If it is not blocked, they can use fire and temporarily block the city gate with wooden carts filled with knives."

"But they cannot always use fire to block the city gate holes. Carts filled with knives can also be knocked open by siege hammers. These are temporary methods. The most dangerous thing is the urn city, which is that another small city is built inside the city gate, and the enemy can stand at the top of the city and shoot arrows downwards."

Dong Hu pointed to the gate of the suspension bridge and said, "The urn city usually only exists in military cities. It is easy to know in advance that the city with urn city is changing rapidly on the battlefield. We cannot simply think that urnju County is just a private city, and we think that the enemy cannot make urn city temporarily. The enemy can use wooden fences and large chariots to temporarily form a urn city. Once the enemy does this, if the commander of the surveillance side is too impulsive and is trapped in the urn city first and killed by the enemy in the city, the consequences will be unimaginable."

Dong Hu pointed to the southeast corner with a smile on his face, and his hands gestured a ninety-degree folding angle.

"The thickness of the corner wall is thicker than the front wall, but because the walls have edges and corners, just like a stonemason hitting a stone, it often does not directly hit the center of the stone, but chooses to hit the edges of the stone because the edges and corners are easily smashed."

"White'er looked at it again. There was a lot of water there, which means that the terrain was low-lying. It was the time of drought in spring and summer. We still couldn't see any clues. If it was rainy in midsummer, the city wall would be soaked in water. After years of soaking, the city wall would be much looser. The enemy might be able to create a temporary urn at the city gate in advance, but they would not choose to create a urn at a corner."

Xiao Dongbai nodded repeatedly.

"Yeah, Bai'er remembers it!"

"hehe……"

Dong Hu rubbed the little girl in his arms and then stood up.

"There is no constant force in the military, and the water is no constant form, so we cannot be bound by dogmatism."
Chapter completed!