The rear army was responsible for defending both sides of the estuary of the Nandu River. The coast was built with complete fortifications. The first line of defense was wooden stakes buried in shallow seas, which could prevent enemy medium-sized warships from rushing to the shore, leaving only the channel for ships to enter and exit unclosed; the second sand embankment built along the coastline was one meter high, two meter wide at the bottom and one meter high at the top, and reinforced with wooden fences. Archers, grenadiers and small crossbows were arranged to block the impact of enemy cavalry and shoot enemy landing troops that had just rushed to the beach.

After the two lines of defense, a trench two feet wide and five feet deep. Because it is close to the sea, the ditch is filled with sea water, and even war horses are difficult to cross. One trench behind the ditch is a five-foot-high low wall built with the mud and sand dug the trench, and military defense is arranged. In the middle, reefs protruding on the ground or artificially built high platforms, heavy crossbows, stone throwers, and rocket launchers are placed.

The stone thrower arranged here is by no means a human towing or counterweight type commonly used in this era, but is a torsional stone thrower with the same principle as the launching of the crossbow, powered by noose. However, it is also a big guy, and it is placed there like a small temple with a flagpole, weighing less than four or five thousand kilograms. It is precisely because of its weight and size, it is too large to be installed on a ship and difficult to move. Of course, it can also be miniaturized. However, Zhao Bing felt that the crossbow with sufficient fire rate and power was used as "city defense cannons".

This instrument is placed with a roller in place, and then a support is added to the bottom of the side to adjust the range of the projectile. The end of the rod arm is fixed through the opening of the large iron hook, and a grenade belt is installed on the top of the rod arm to place the stone bullet. A stone projectile is placed on the grenade belt. Four soldiers on both sides of the trench are rotated and the noose is tightened by the ratchet mechanism to pull the projectile arm down until the rod arm is almost flush with the ground. When released, a large wooden hammer is hit to the iron structure handle and fire it. When the rod arm is released, it bounces upwards and throws the stone bullet out of the grenade belt.

Zhao Bing also suffered a lot of trouble when designing it. If the upper end of the rod arm was made into a seat to place a stone bullet, the end of the rod arm must be made large and heavy. If it is used to block the cross-bone of the rod arm, it also needs to be reinforced. This will make the chance of throwing stones more bulky and not conducive to manufacturing and movement. So he thought of using a grenade belt, and the length of the belt actually becomes an extension of the rod arm, which will not cause significant increase in the weight of the rod arm.

The lever principle used by the catapult is that the longer the lever arm, the longer the distance swept through the air, and the farther the projection distance. When using a grenade belt, the lever arm can be made to gradually thin from a thick head upward, and the lever arm can be much lighter at the same time. Compared with the lever arm with a thick end to place the projectile, the speed is much faster when rebounding, and the power increase is also surprising. The difference is the same as the difference between the small slingshot and the large slingshot used by school children to shoot stones.

Zhao Bing once conducted an experiment. Although this heavy torsion catapult did not reach the record that it could throw a horse weighing 500 kilograms into a city of two or three hundred meters, it would be completely terrifying to throw a fat man of two or three hundred meters away at the limit. If such a large stone hits a warship, even a large warship would be unbearable. If it hits the top of the ship, he felt that he could pierce the ship in one fell swoop. If it was added three or five kilograms of stones were thrown out in the way of the Heavenly Girl scattering flowers, it would definitely be able to lay a large area, and it would be much more economical than rockets...

"The stone thrower, loading the shotgun, four hundred steps away, and the target enemy ships on the river are ready!" The command post of the commander of the rear army Zhuang Siqi was set on a high slope. The enemy troops landing on the sea were either sunk or overturned under the bombardment of rockets. However, the Badulu ship could carry fifty soldiers. With their rowing together, the warship was already very fast, and the speed was faster with the help of the rising tide. The ship was small, which made half of the ships avoid the bombardment of rockets. The subsequent enemy ships were still used to the sea estuary. Seeing the enemy ships rushing up the sea estuary, he ordered.

"Prepare is completed!" Guantong hand saw the signals sent back by each gun position and reported.

"Start!" Zhuang Siqi ordered.

‘Hu, Hu…’ Ten stone throwers were set up at the coastal estuary to fire at the same time. The stones wrapped in the belt drew a parabola and flew towards the sea with the sound of wind. The sea lift was trumpet-shaped and narrowed as it went deeper. With the hidden piles set up, the passage was only fifty steps wider. Although the stone throwers were not accurate enough, they were still more reliable than rockets, with thousands of stones as big as bowls hitting this area.

Everyone knows that a glass that falls from five or six floors high contains enough potential energy to hurt a single one, and it will be a deadly thing if it hits a single one. These stones falling from the air are more than ten times more powerful than a cup. Of course, those enemy soldiers are not fools. Seeing an "air attack", they raise their shields to block them. But how can these wooden shields be blocked? They are instantly smashed and smashed, but blocking is better than hitting directly. Although they suffer some skin injuries, they will not be seriously injured. Some are unlucky, and those who are directly hit will all burst into brains and bones and tendons.

The warship is much larger than the human, and the chance of being hit is naturally higher. It is better to hit it in a thick place. Some stones penetrate directly through the gangway, and the people on the ship suffer. The small holes can still be blocked. Scoop out the water, and the big ones can only swim ashore as ducks. This round of attacks caused great damage to the enemy, and there were less than ten enemy ships blocked by rushing through two rounds.

However, the elite are elites. After decades of war, the Mongolian army suffered great losses. However, they also annexed the surrounding nomadic tribes and many foreign tribes, including the Han people in the north. They could still maintain more than half of the infantry and cavalry forces, and accounted for 30% of the navy. Therefore, after suffering huge losses, they still rushed to the beach regardless of everything, trying to seize a foothold, and even failed to rescue their companions who fell into the water.

"Heavy crossbows are prepared, flowering bullets, targeting enemy ships 200 steps away!" Zhuang Siqi looked at the enemy ships that had become sparse on the river and ordered.

Now, because of wasting rockets, the matter of punishing Liu Wenjun and Zhang Zizhen for eating big pots every day has spread throughout the army. Of course, Zhuang Siqi also needs to take it as a warning. Therefore, after using rockets to bombard the dense enemy landing fleet, he used stone throwers to attack the lost enemy ships. Then the rest are not suitable for large-scale coverage and attacks, and the crossbows are suitable for precise targets.

"Report, the crossbow is ready!"

"Start!" After receiving the reward from Guantong's hand, Zhuang Siqi immediately ordered...

…………

"Your Majesty, this scorpion cannon is really powerful, even more powerful than the bed crossbows we used to equipped in the past!" Zhang Shijie smiled at the enemy who was smashed by a torsional stone thrower and smirked.

"Scorpion cannon?! Do you call this kind of stone throwing machine a scorpion cannon?" Zhao Bing was stunned when he heard this, put down his telescope and turned his face and asked.

"Yes!" Zhang Shijie said, "After the launch of the stone thrower in the army, the arm of the lever is like a scorpion's tail. The grenade belt is like a hook piercing at the tail end. The stone bullet shot out is powerful. All the people in the middle died immediately, just like a scorpion. I look very vivid. Do you think it's wrong?"

"No, no, everyone is very vivid, it's much better than what I think. Let's call it Scorpion Cannon in the future!" Zhao Bing waved his hand and smiled.

He was so worried that he heard Zhang Shijie's words that he was so nervous that when the torsion stone thrower was invented, the Greek soldiers really called it the scorpion cannon, but it disappeared because it was too secreted as early as BC. You must know that there were still many limitations in the exchange between the East and the West at this time, but someone called out the "nickname". How could Zhao Bing not be nervous? If someone knew the secret of the sling, he would not enjoy these two weapons that were powerful enough to change the outcome of the war.

"Oh, what does Your Majesty think this stone thrower looks like?" Zhang Shijie was curious and asked the little emperor.

"Haha, I feel that this stone thrower is like a wild donkey when he loses his temper and kicks the stones on the ground!" Zhao Bing said with a smile and kicked his legs backwards. In fact, this "wild donkey" is another name for the Greeks.

"Haha, Your Majesty is so funny!" Seeing Your Majesty's clumsy imitation of the donkey and trying to get rid of his son, Zhang Shijie was stunned for a moment, and was amused by His Majesty, who was still full of childishness, and said with a laugh.

"Why, don't I learn something like this?" Zhao Bing asked as a serious person. In fact, the closest contact between him and a donkey in his previous life was that the donkey meat was burning. He had seen donkeys from the animal world, but it is common for horses to kill him now. But seeing Zhang Shijie's lewd smile, I felt relieved. After all, the aesthetic views of the East and the West also have the same? It's a pure coincidence!

"This... although not exactly like it, it's 80%." Zhang Shijie saw that His Majesty was serious, but he was embarrassed. He said that it seemed neither good to look like it nor not. He held it in a long time and said ambiguous words.

"I remember this. I will ask them to find a donkey to see tomorrow." Zhao Bing said in contemplation for a moment. He was secretly happy in his heart. Zhang Shijie was also an honest person. If he was a sensible person, he would definitely show himself how the donkey would hurt his son. If he felt it hurt, he would praise the person he learned. He insisted that the donkey would beat him like this, and would never be so perfunctory.

"Your Majesty, I'm afraid it's hard to find donkeys in Qiongzhou, but there are many horses in the army. They are almost the same when they are about to fall down." Zhang Shijie frowned and said in embarrassment, and gave His Majesty an idea.

"Hey, I don't agree with the words of Shushu. Since donkeys and horses are two kinds of beasts, there must be differences. I must look at Qiongzhou and can't find a donkey!" Zhao Bing was almost injured after hearing this. Why was Zhang Shijie so funny? He took his words seriously, and he pretended to be more serious and said.

"Yes, yes..." Zhang Shijie nodded repeatedly, and complained in his heart. After all, His Majesty is still a child, and he has to work hard to find a donkey for him.

‘Boom, boom, boom…’

"Your Majesty, the rear army has fired a cannon!" Just when Zhang Shijie didn't know how to continue talking on this day, the west thought of explosions one after another. He secretly chanted Amitabha Buddha, and the cannon sounded like a save his own life.

Zhao Bing looked at the explosion and saw that the remaining enemy ships turned into broken wood and rotten boards under a fierce round of crossbows. Some of them could move and pulled off their heavy armor and fluttered, or used the wooden shield as a lifebuoy. However, the dead and not dead were pushing their lower bodies into the shore involuntarily. These living people gradually gathered together, rushed to the shore under the arrows of the Song army like locusts, and lie in the depression.

"Are they feint attacking?" Zhao Bing estimated that the group of enemy soldiers who came ashore had about a hundred people. They threw away their helmets and removed their armor, and some of them even sank into the river. But there was no support ship to follow him. What can they do with this little man!

"Your Majesty, they should be a feint attack, testing the reality of our army and preparing for the next attack!" Zhang Shijie replied.

"I'm wondering, the narrow waterway in the river is not a place for military use. Why don't they land on the coast?" Zhao Bing said that the enemy's first round of attack just now sent thirty Badulu warships, with a team of 1,000 people. The river surface is narrow and the impact surface is limited, and it is easy to be attacked by the opponent's concentrated firepower on three sides. No matter how you look at it, he has no chance of winning, which makes him very confused. Why was the waste of troops so wasted.

"Your Majesty, I think Ali Hague probably has seen through our plan. He must be worried about our naval army intercepting him, so he wanted to land and gain a foothold as soon as possible, otherwise the losses would be greater." Zhang Shijie analyzed, "From the Nandu River to go straight to the Fucheng. He thought that as long as we could land here and control the estuary, our coastal defense line would collapse, and we could only give up the Fucheng and retreat south. However, in my opinion, their enemy troops should be eager to succeed, and the two sides did not cooperate well, otherwise they could attack Haitian Island in two ways, and control this place and achieve the same goal!"

"Well, Shushu has a good analysis. I'm afraid it's going to start attacking there!" Zhao Bing pointed to Baisha Island and said. He knew that his "counter-espionage plan" could only be hidden for a while. With Ali Hague's head not difficult to see through after discovering Sodu's action, he still believed that most of the Qiongzhou naval army was pursuing Sodu. Now his strategic intention has been exposed. If he returns to the flight, he will have no chance and may be chased by himself. Therefore, as Zhang Shijie said, he launched an attack with all his own bets.

"Oh, Liu Zheng's resignation to the enemy will cause harm for a hundred years!" Zhang Shijie also turned to Baisha Island and looked at it.
Chapter completed!