Li Shiji led the army to look at the scene in front of him with some amazement, at this moment near the mouth of the Yalu River, dozens of sailboats with unique shapes are going upstream, although their speed is not fast, but because the speed of the river at the mouth of the sea has slowed down, it is not difficult to go upstream.

And they didn't go too far, but at the point where the river at the mouth of the sea narrowed, the ships began to gradually approach each other.

These are not very large, about 500 tons of displacement, and its size is different from that of sea vessels, more like inland ships, with a more bloated belly in the middle, these ships are about 50 meters long, and the width of the middle deck is about 15 meters.

Their sails are located at the bow and stern, and the middle deck of the ship is flat at all, and the position of their middle deck is a unique shaped steel plate.

When they begin to approach each other, the steel plate with a width of about four meters in the middle and a thickness of 50 mm unfolds from the left and right, and when the plate is unfolded, it immediately forms a steel plate 20 meters long, 4 meters wide and 50 mm thick.

This unique steel plate has a special buckle on the edge, and when the ship arrives at the designated position, the engineers on the boat quickly lower the sail and throw down the anchor made of a huge reinforced concrete.

Reinforced concrete anchors are used because they can be discarded if they are not easy to collect.

When the anchor is stable at the bottom of the river, the anchor chain is pulled by manpower and the pulley block structure on the boat, the position of the hull is adjusted, and then all the sails are quickly retracted, and then the boats are quickly brought closer to each other through the ropes connected to the boats on both sides.

As soon as the ship approached, the engineers quickly began to connect the steel plate buckles on both sides directly with thick steel bolts.

A ship closest to the edge of the river rushed directly onto the river shoal, let it run aground close to the river, and the edge of the steel plate extending from the boat was quickly driven directly into the ground with a long steel drill.

On the river, ships quickly approached and connected with each other, and in less than five hours, a steel bridge with a total length of about 1,000 meters and composed of more than 50 special sailing boats was built on the Yalu River!

When the entire bridge was built, the faces of the Datang soldiers who stood by the river and watched all the time were full of shock!

Even Li Shiji and his generals were full of shock, not to mention other ordinary soldiers.

Although the Yalu River is not as majestic as the Yellow River and the Yangtze River, it is so wide that people in the past have never had any ability to build bridges on it!

But now, Datang can build a bridge in just a few hours!

How powerful is that?!

"This was also invented by His Highness?" Hou Junji asked.

"Yes! I never imagined that such a pontoon bridge could be built in such a short time, and that there are such special vessels, and most importantly, they can be built on such a huge river, and this pontoon bridge can be dismantled at any time, which is the most important thing. Li Shiji nodded seriously.

"Your Highness is really familiar with military books, many things that are very common to us, but Your Highness can always invent incredible things." Hou Junji, they were all emotional.

They were amazed by the new format and the speed of the game, but they weren't surprised by the approach.

Because this kind of boat and bridge troops that all countries in later generations have, and the configuration that all countries have in their armies, but in fact, they don't want to play as early as more than 2,000 years ago in China.

A similar pontoon bridge, as early as the 50th year of King Zhaoxiang of Qin, was built on the Yellow River in Pujin Pass in Yongji City, Shanxi Province, and the first military pontoon bridge in human history was built.

This location has been built in various dynasties in later generations, and later in the seventh year of Song Kaibao, the first pontoon bridge was built on the Yangtze River, and the yellow and black dragon boats used have been almost the same as those of later generations.

This is why, more than a thousand years later, Sun Tzu's Art of War can still be respected all over the world.

Because of such a thing as playing the art of war, the ancestors have long been tired of playing with all means.

As for what kind of situation you can use, it depends on your own ability to integrate it.

"Cross the river!" After confirming with the Zhouqiao troops, Li Shiji directly issued an order.

All of them were built by 500-ton boats, and the deck was made of steel plates, allowing a column of six people to cross the bridge at a fast pace!

In other words, if the 100,000 infantry of the Datang Dynasty lined up in a neat line and ran across the river, they could basically complete the passage within nine hours! And it took three days for Khudar's 50,000 troops to cross the Yalu River!

This is because they crossed the river by boat at the narrowest point, and there were no bridges. That's because they have a lot of ships, otherwise it would have taken longer.

Of course, the actual passage time of the Tang Dynasty was slightly longer than this, because not only did a large number of cavalry cross the river directly on horseback, but also large engineering equipment had to pass through the bridge.

But even so, it only took three more hours, and when Li Shiji and the others crossed the river in the middle of the night, an earth-shattering explosion came from the direction of the Black Bone City in the distance!

It was the army of the Tang Dynasty that took advantage of the night to directly blow up the walls of the Black Bone City.

It is estimated that by the time dawn tomorrow, the battle in Black Bone City will have a result.

But it's not Li Shiji's responsibility there, it's Xue Wanche attacking the Black Bone City, and then the Tang Dynasty's troops will go directly to Pyongyang!

It is estimated that by tomorrow, Yuangai Suwen in Pyongyang will know the news of the fall of the Black Bone City, and I hope he will misjudge the time when the Tang army will cross the river, and at least usher in three days for the Tang Dynasty.

At that time, the Tang Dynasty could choose a suitable battlefield, and even directly arrived in Pyongyang to launch a final general attack on Goguryeo.

Because Goguryeo has always had scouts along the Yalu River, they were driven away by the Tang Navy, and there must have been Goguryeo soldiers stationed on the other side of the Yalu River on the side of the Black Bone City.

They would get the news when the Black Bone City was broken, so it was impossible to hide the news from Yuangai Suwen no matter what.

But it doesn't matter, because Li Shiji has already communicated with Li Daozong of Silla, and when they crossed the river on their side, they had gathered 50,000 elite Tang elites, and tens of thousands of Silla auxiliaries of the Silla Army also launched an attack under the leadership of Li Daozong.

The change of the times is huge, and it is not an exaggeration to say that without any preparation from the enemy, the city mine is enough to blow down any city wall.

When the city walls could not be used as a protection for the enemy, the rain of arrows and the medium-sized bed crossbow of the Tang Dynasty were enough to become a nightmare for all enemies.