Faced with the death order from Suiyang, even if Tang Ying and Le Yi wanted to spare the lives of the Song army, they had no choice at this time.

Fortunately, although Dai Yan gave such a death order, he also brought reinforcements. Now that the domestic armies of the Song State have been mobilized and they still need to defend the Northern Qi State, where will the Song State get more troops?

In fact, the reinforcements sent by Dai Yan are not considered an army, but an engineering team. This engineering team is supplemented by several Mo disciples as the core, plus hundreds of craftsmen who are considered to be top-notch even in Taoqiu City. This kind of engineering team can be regarded as an engineer with the characteristics of the Warring States Period, and they were sent by Dai Yan to help the Song army break through Jinling.

Since the end of the Song Civil War, the new weapons have achieved excellent results in the civil war, and Dai Yan has become more and more interested in the new weapons developed by the Mo family. He rewarded Mohist students who had made outstanding contributions to physics and mechanics, and allocated more funds to Mohist craftsmen to develop more advanced weapons.

Before the Mo family defected to Dai Yan, they continued to build defensive weapons to increase the cost of war between nations, which gave the Mo family rich experience in defending weapons. And when the Mo family defected to Dai Yan, especially the foreign policy of the Song State, began to become active, and there was already a tendency to open up outward, siege weapons suddenly became important to the Song State, and the research and development of siege weapons began to become the most important task.

In Dai Yan's opinion, although the Song Kingdom now has advanced weapons such as bed crossbows and ballistas, it seems that it has a great advantage in siege. However, this is entirely because the Song army did not encounter a truly strong city before, once it encountered a real strong city such as Jinling, the Song army could not quickly break the city, and the troops under the city would inevitably face the danger of defeat.

However, it is indeed very easy to talk about more powerful siege weapons, but it is not easy to turn them into reality. Because of their many years of experience in manufacturing machinery, the theoretical support of physics, and the help of Taoqiu's industrial power, the Mo craftsmen finally developed a powerful siege weapon.

The newly developed siege weapon of the Mo family is not a new siege weapon, but only a modification of the siege weapon that originally existed in all countries. In the eyes of the disciples of the Mo family, a real strong city must require more powerful forces to break it, so it is only necessary to build a more powerful trebuchet.

The trebuchet developed by the disciples of the Mo family is no different from an ordinary trebuchet in principle, and it is a weapon that uses the principle of lever to throw stone projectiles. Structurally, it is also composed of a base, a fuselage, a lever, a hammer and a projectile bag. Before the projectile, as long as the projectile bag at the front end of the long arm of the lever is loaded with stone bullets, and the hammer at the rear end of the short arm of the lever is quickly put down, the lever is immediately cocked, and the stone bullets in the projectile bag will be thrown out at a very fast speed!

The only difference between it and other trebuchets is that it is extremely powerful, and it can easily throw a heavy stone projectile of 200 catties to a distance of 400 meters! Such a powerful trebuchet can no longer be called a trebuchet, it should be called a catapult!

When Dai Yan saw this weapon for the first time, he saw the passage of the stone projectile thrown by the catapult, and the stone projectile it threw could smash through the ground seven feet when it fell to the ground! In later generations, he had heard that the Mongol army used the Hui cannon to destroy the country and destroy the city. In his mind, this kind of catapult made by the disciples of the Mo family now, even if it is not as powerful as the return cannon, I am afraid it is almost the same.

What is rare is that this kind of catapult made by the Mo craftsmen is not only powerful, but also extremely accurate. This weapon can easily concentrate on a pre-set location by simply firing three to five stone bullets on the ground to adjust the firing range. This means that as long as the Song army has enough time to adjust its accuracy on the battlefield, this bulky weapon can be used like a ballista.

And this weapon, although the advantages are obvious, the disadvantages are no less obvious. Because it is too bulky, the materials required to make such a catapult weigh hundreds of thousands of catties, and the finished product itself also weighs more than 100,000 catties!

And because such a catapult throws a stone projectile, it converts the potential energy of the hammer itself into the kinetic energy of the stone projectile, which not only needs a stable and solid environment when firing the stone projectile, but also causes an extremely amazing impact force when the hammer falls, so such a weapon cannot be moved to the ship for direct use.

Even because the finished product of this weapon is so cumbersome, it is impossible to even use ships for transshipment! Therefore, the only way to use such weapons is to make them ready where they are needed.

When the engineering team sent by Dai Yan came to Jinling City, the army of the Song State had already arrived here. Prior to this, the Song army had launched several tentative attacks on Jinling City under the leadership of Le Yi, but they were all stopped by the strong defenses in Jinling City.

In that short exploratory attack, the Song army found that the defensive equipment in Jinling City was readily available, from the crude thunderstone rolling wood, to the cottage bed crossbow made after the Song army's bed crossbow, plus the whale oil and asphalt that were available in all the cities in Jiangbei before. Judging from the unhesitating attitude of the Chu army, the material reserves in the city must be extremely rich. If the Song army wanted to take the city through attrition, they didn't know how many soldiers' lives would be consumed.

Now all the hopes of Tang Ying and Le Yi are pinned on the reinforcements sent to them by the sovereign. This kind of black technology formed by the Song Kingdom after years of accumulation did not disappoint them.

When the Song army's engineering team came to Jinling City, it first selected nearly 5,000 soldiers from the Song army and asked these soldiers to cut down all kinds of tall trees from the mountains and forests around Jinling for the Song army's use.

These pristine trees, treated by these highly skilled pottery mound artisans, are quickly transformed into a variety of high-quality woods. These woods can be made into less complicated things such as the fuselage and base of the catapult.

And the most central things in catapults, such as the lever that connects the stone projectile to the hammer, cannot be made on the battlefield. The weight of the catapult itself is extremely heavy, and when the stone projectile is thrown, the potential energy of the short end of the lever hammer needs to be converted into the kinetic energy of the stone projectile, and the moment of its projection will produce extremely strong pressure on the lever, which has extremely high requirements for the strength and toughness of the lever.

In order to create such a suitable lever, the Mohist craftsmen experimented with a variety of materials, including various woods, and even copper and iron rods, and in the end, the materials used were only barely met by merging wood and steel.

In this catapult, in addition to the levers, there are several other special materials that must be completed by relying on the industrial power of the potter's mound. With the restrictions of these materials, the Song State could guarantee that even if the drawings and even prototypes of this catapult fell into the hands of the enemy country, the other party would not be able to manufacture such weapons because they did not have enough industrial strength to manufacture suitable materials!

This is also the consistent idea of the primitive industrialization developed by the Song Kingdom: insist on mastering the core technology. Advanced siege weapons are related to the safety of the Song Kingdom, and the Song Kingdom will naturally not easily let the country quickly master these black technology weapons.

After all kinds of materials were ready, the entire engineering team composed of Taoqiu craftsmen began to assemble various materials under the personal command of several Mo disciples. When the catapult was finally completed, it was like a silent beast lying under the city of Jinling.

Although it was motionless, the momentum it revealed had already frightened battle-hardened generals like Tang Ying and Le Yi.

The Song army built more than forty of these catapults, and it took hundreds of craftsmen nearly twenty days to complete these tools alone. When all the catapults were completed, the various auxiliary tools used by the Song army in order to siege the city were also in place.

Nearly 1,000 bed crossbows, hundreds of ballistas, plus nearly 100 ladder trucks, as well as thousands of Song sailors and nearly 100,000 Song troops patrolling outside the Yangtze River, the entire Song State's southern expedition has all been mobilized here.

At this moment, as long as Tang Ying, the commander of the Song Army, gives an order, this powerful force will completely pour into Jinling City!