Escaping from death, whether it is for the surviving Liu Ji's team, or the endless stream of Tang Army brigades who came across the river, are a huge encouragement in morale, and it is manifested in action, that is, everyone is vying to be the first.

Only a few people who know the inside story understand the danger here.

Liu Ji is a staff officer, and his best skill is not special operations, but planning, in a staff officer's dictionary, there is no difference between success and failure, only response measures for various different consequences, therefore, from the very beginning, he did not take the Fujiqiao completely as the only choice.

What should I do if I can't take the bridge? This is the method he and Yu Wensheng came up with, abseiling, a distance of about a hundred paces, artificially creating a height difference, using the action of gravity, falling quickly, when his squad was carrying out environmental adaptation training on the snow-capped mountain plateau, Liang Zai's Chinese army has been carrying out this kind of training, otherwise, how can it achieve good results.

What was fired by the crossbow machine, it was not an ordinary crossbow gun, its front end, in the form of a five-claw barb, in order to increase the grip, similar crossbow guns, a total of thousands were created, the more difficult thing is the right rope, in order to increase the speed of the slide, the skin is also wrapped on it, which also caused another trouble, the speed is too fast when landing, but who cares about these at this time.

Hundreds of building cars, can descend hundreds of people at a time, it only takes one or two hours, most of the foot soldiers can pass, this new force will control the two banks of the Poyi River, for the next move to provide security.

After all, horses, baggage, and even high-ranking generals like Feng Changqing could not cross the river in such a way, you know, not every rope is safe, in case it breaks halfway, the gods can't save it.

So, Liu Ji thought of another way, to build a semi-permanent bridge over the river, and the materials used were a bit staggering.

Iron cables.

This idea comes from a later movie, the suspension bridge that is still erected on the Dadu River in Shu Province, both the terrain and the width are very similar here, of course, now they do not have so much financial resources, can only keep everything simple, this is Liu Ji's so-called semi-permanent.

These suspension cables are composed of eight thick iron chains, each chain is connected by two thousand oval iron rings, one iron ring weighs half a catty, and one iron chain is more than a thousand catties.

Of course, the best way is to swim across the river and then find a way to fix it, but the Poyi River under his feet is a 'weak water' without much buoyancy...... Trebuchet.

Liu Ji did not have much research on the mechanical aspect, nor did he know much about the operation principle of the ancient trebuchet, only that it conformed to the principle of leverage, and the force required to throw one end of such a heavy iron chain was also huge, so the surrounding area of the trebuchet was surrounded by thousands of sergeants.

Seeing this big thing being assembled little by little, Feng Changqing and the others were also dizzy, the main throwing arm more than ten steps long was made of the trunk of a whole big tree, and there were still residues of bark on it, and the wooden tips used as a transmission device were as many as fourteen, which was almost the limit of the human trebuchet.

Unlike counterweight trebuchets, the advantage of this kind of trebuchet is that as long as you have enough manpower, the theory can produce a large enough throwing force, and it can concentrate thousands of people in one point to create a huge force.

Of course, the disadvantage is that it is not practical, so many people, just to operate a trebuchet, is a great waste of human resources, but in a specific place, there are often unexpected effects, such as in front of the eye.

"Liang Shou captured, the people under the official have been prepared, and I ask your subordinates to give an order."

Yu Wensheng personally led people to climb up and down, and it took a while to complete the installation of this huge guy, an iron chain has been hung on the top of the throwing arm, in order not to fall apart, he added double the support wood, and then gritted his teeth and went to find Liang Zai.

Liang Zai didn't agree immediately, but turned his head to look at Feng Changqing, who nodded, and he strode forward and waved at his subordinates.

"Brothers, just follow what we practiced before, and listen to a certain command."

Under his command, hundreds of people shouted in unison, slowly pulling the ropes tied to the wooden tips, and when they were close to the highest point, all of them slammed into force, and the long throwing arm drew a quarter circle, throwing the iron chain head hanging at the top into the air.

The eyes of everyone on both sides of the strait were all looking at the iron chain flying in the air, the head of the chain that was vigorously thrown, and as the height rose, it slowly brought up the chain behind it, like a long snake flying, slowly heading towards the opposite bank.

Liu Ji was also watching, and at the same time calculating its approximate landing point in his heart, sure enough, the thrust generated by this trebuchet was not trivial, and the iron chain flew over his head, more than a dozen steps away, before it fell with a whistling sound, fortunately, the speed was not fast, and the surrounding Tang troops avoided it one after another, seeing it fall on the muddy ground.

"Not good!"

Liu Ji suddenly felt that something was wrong, and after the iron chain fell to the mud, he quickly shrank towards the opposite bank, because of the effect of the section hanging in the air on the river bank.

On the other end, it is good to say that it was fixed on the ground by Yu Wensheng, who had been prepared, but this end of the river bank is shrinking faster and faster, because its weight is too large, even if someone wants to pounce and pull it, it will not work.

Liu Ji casually snatched a spear from a sergeant's hand, and before he could make a move, a black shadow rushed over quickly, and the spear in his hand stabbed underground, accurately passed through an iron ring, and was nailed into the mud.

"Hold it!"

Liu Ji shouted, and in the same way, a shot was stabbed in the gap of the iron ring, stopping the sliding trend of the iron chain, and the sergeants he called stepped forward one after another, pulling it with all hands and feet, and dozens or hundreds of people worked hard together to finally tighten the chain.

The rest was easy, and the method of fixing it was very simple, a few thick wooden stakes were hammered into the mud by the sergeants with mallets, one end of the iron chain was tightly wound around the top, and then fixed with iron drills, and an iron rope was formed on the surface of the river.

With the same method, eight iron chains were thrown one by one, with six as the base, two as the bar, the prototype of a suspension bridge was formed, and then the prepared planks were tied up one by one, this two-step wide, more than 100 steps long simple flying bridge appeared in front of everyone's eyes like a trick, the Tang people were still as calm as ever, and the people did not know how to describe it in words.

You know, it took more than seven months for the Tubo people to build a rattan bridge, and it didn't take more than two hours from beginning to end, what kind of power is this?

He was very glad that his choice was to stand with these Tang people who had been blessed by the gods.

There was no chance, Xi Dongzan lamented again, and it was not until the Tang cavalry led the horses across the river from the bridge that he was truly dead.

I thought that the Tang people had no way to build bridges, and the horses couldn't come over, so they led the cavalry and could wait for the opportunity to start, after all, even if it was not cost-effective to fight hard, they could also be harassed, but who would have thought?

In such a short period of time, they built an iron bridge!

That's iron, the Tubo people have to use precious horses, in exchange for the rough iron, they are actually used by them casually to build bridges, this is more discouraged than losing a battle on the battlefield, because defeated, it's a big deal to win back next time, the huge gap in national strength, what to win?

Xi Dongzan gave birth to fear for the first time, Datang, like a mountain in the distance, is invincible and cannot be climbed, they have paid so much manpower and material resources, can they really stop it?

Compared to this force, what is it to kill one or two warriors?

"Let's go, go back to the city of Bolao."

Xi Dongzan kept his face calm, turned the horse's head, and never looked at it again.