When the Wei army arrived at the city of Jiuyuan, it only set up a battle formation in the south of the city, and did not adopt the method of besieging the city from all sides.

Besieging the city on all sides requires enough troops, the art of war is cloudy, ten rules to besiege it, that is to say, if you want to besiege the opponent, you need ten times the enemy's strength, even if there is no ten times the strength, at least six or seven times more troops, now the strength of the Wei army is not to say that it is twice as much as the opponent, I am afraid that it is only less than half of the opponent's strength, such a force, if you want to besiege the city, it is really not enough.

Therefore, if he wanted to attack Jiuyuan City, Cao Liang could only use the method of concentrating his forces and attacking from one direction, in order to prevent the Huns from counterattacking, Cao Liang adopted the strongest method when he set up camp, dug deep trenches around the camp, and set up a large number of antlers and horses to prevent the attack of the Hun cavalry.

After all, the strength of the Hun cavalry is obvious to all, although in the battle of Dongguan, Cao Liang used the side car to thwart the attack of the Huns, but this does not mean that the Hun cavalry lost the threat, so the defense of the camp is extremely important, if the Huns find the opportunity to take advantage of, the situation of the Wei army will be unfavorable.

As the last battle with the Huns, Cao Liang naturally did not dare to take it lightly, don't look at the Pingbei Army since the Northern Expedition, successive battles, several times defeated the Huns, but so far, the main force of the Huns has not been hit hard, so the Huns' combat effectiveness is still not to be underestimated.

Cao Liang has a very clear understanding of this, winning without arrogance, defeat without discouragement, this is the real way to win.

The successive victories over the Huns undoubtedly boosted the morale and confidence of the Wei army, but at the same time, it also bred a lot of emotions of underestimating the enemy, believing that the Huns were nothing more than that.

This kind of sentiment of underestimating the enemy is actually very dangerous, not to mention that the Pingbei Army is not as good as the Huns in terms of strength, even if the Pingbei Army has the strength to defeat the Huns, it will be arrogant, then the defeat of the Pingbei Army will not be far away.

Therefore, before this expedition to Jiuyuan, Cao Liang had warned the generals very seriously that the decisive battle with the Huns this time was still an unfavorable situation in which we attacked the strong with the weak and fought more with less, so we must not have any idea of underestimating the enemy, and we must continue to maintain a rigorous fighting style.

Establishing a camp is a guarantee, and when attacking Jiuyuan City, it is more necessary to focus, Cao Liang put the Yue cavalry battalion and the tun cavalry battalion on both wings of the battle formation to ensure that the two wings are not attacked by the Hun cavalry.

The three infantry attack units of the infantry battalion, the Changshui battalion, and the shooting sound battalion formed three phalanxes, and under the escort of the partial van car formation, they marched slowly and slowly towards Jiuyuan City.

Among the phalanxes, the most striking are the dozens of counterweight catapults.

The new type of catapult was more than double the height and width of the catapults used by the Wei army, and they slowly moved forward with the infantry phalanx, giving them the feeling of standing out from the crowd.

These catapults are made of thick logs, thick and sturdy, like a giant Mac, with a strong visual impact and shocking effect.

After marching all the way before, the ordnance battalion naturally had no chance to build such a big thing, and after arriving in Jinyang, Cao Liang put the construction of the catapult into practice.

Jinyang is the largest city in Bingzhou, with sufficient resources, including material resources and human resources, which is of great benefit to the construction of large equipment like catapults, especially after Cao Liang served as the governor of Bingzhou, he has the power to mobilize these resources, and the construction of catapults has naturally become a matter of course.

As early as Luoyang, Cao Liang and Ma Jun completed the design of the equipped catapult and built a prototype, but in order to prevent technical leakage, Cao Liang resolutely dismantled the catapult after completing the test.

However, the design drawings were preserved, and he had been looking forward to a suitable opportunity to rebuild these catapults and actually equip them in the army for practical purposes.

Now that Cao Liang commands an army and a state, it is time for the catapult to be born.

But after all, building a catapult is a huge project, and the raw materials required are very large, and only the craftsmen of the ordnance battalion are not enough in terms of quantity, because Cao Liang wants to make the catapult form a combat scale, only a few are not enough, at least build dozens of catapults first.

Cao Liang initially set the production quantity of 50 vehicles, and purchased raw materials according to this quantity, and in addition to the craftsmen of the ordnance, Cao Liang also specially recruited hundreds of craftsmen, blacksmiths and stonemasons from Jinyang City to join the team of building catapults.

Prior to this, Cao Liang had stopped the manufacture of crossbows and other ordnance, and the ordnance battalion turned to the construction of catapults.

Compared with the shoddy towed trebuchets equipped in the Wei army, the equipped trebuchets built by Cao Liang this time are much more refined, and most of the previous towed trebuchets are disposable products, and a large number of them will be damaged during a single use, so that the power of the trebuchet is menacing in the early stage, and it becomes dumb in the back.

And these counterweight catapults, each part is calculated and designed by Ma Jun, the whole vehicle components are strong and grand, in the key stress parts, but also use reinforcement measures to increase its durability, so as not to fight only one battle and scrap into a pile of rotten wood.

Therefore, the process of building these catapults is complicated, labor-intensive and labor-intensive, and it is just an ordinary stone bullet, Cao Liang requires excellence, requiring stonemasons to carve the stones into stone balls, with the same diameter and size, and the same weight.

Compared with polygonal stone bullets, the trajectory of the spherical stone projectile is much smoother, and the accuracy of hitting is also high, and this kind of standardized stone projectile is easy for the gunner to adjust, and the controllability is relatively high.

However, in comparison, the production of this kind of stone bullet is much more difficult, far less than those ordinary stones to act as stone bullets, only the right amount is needed, there is no need to consider its shape, and the workmanship is much different.

Cao Liang invested a lot of manpower and material resources to build the catapult in the year after the formal equipment of the army, but also caught up with the decisive battle with the Huns, because the Wei army to face a difficult task, so the catapult, will play a very important role.