Liu Xuan led the army towards the north, and along the way, he kept thinking about what weapon to use against Nangong Jin.

When it comes to advanced weapons, Liu Xuan's first thought is the atomic bomb, but for him, let alone the atomic bomb, he may not even be able to make an ordinary pistol.

Not to mention tanks and planes, engines will not do.

Just as Liu Xuan was thinking hard about countermeasures, the army passed through a dry saline-alkali area, and suddenly, Liu Xuan's eyes flickered and saw white crystals on the ground that shimmered with a faint crystal light.

The surface of the stone of the lens is extremely rough, and at first glance it is just an ordinary stone, in fact, it is an ordinary common stone that has no effect, but Liu Xuan recognized it at first sight, those stones are the legendary saltpeter.

What is saltpeter? People in this world may not know it yet, but they know that saltpeter is one of the raw materials of gunpowder.

I have the impression that gunpowder, one of China's four great inventions, is mainly composed of saltpeter, sulfur and charcoal.

Black gunpowder is made from a mixture of these three substances.

"Stop!" Thinking of this, Liu Xuan immediately jumped out of the carriage and picked up the saltpeter on the ground, with an excited look on his face.

"Your Majesty, this thing is very ordinary, why is the emperor so happy?" Liu Yi stepped forward and asked softly, now that he is guilty, he has to care about the emperor's every move.

Liu Xuan glanced at Liu Yi, and couldn't help but feel a little proud in his heart, ancient people are ancient people, there is really nothing unusual about this thing, but it can indeed make the legendary gunpowder, how can they understand its wonders.

"Send the order down, let the whole army find such a stone here, put it in your pocket and take it, Liu Yi, you must take the next town." Liu Xuan did not directly answer Liu Yi's words, but ordered.

As soon as Liu Yi heard that he was asked to make up for his merits, he immediately bowed down and took the promise, and the herald took the stone, identified it for a few seconds, and remembered it in his heart, and hundreds of heralds found the saltpeter and spread it to the army.

So, from a distance, an army of 600,000 people was densely packed on this barren and dry land, looking for the ordinary stones that Liu Xuan said.

More than an hour later, Liu Xuan's carriage was already full of saltpeter, and every soldier would carry a fist-sized saltpeter in his hand or pocket, and the saltpeter on the ground was also swept away.

Liu Xuan looked at the cart full of saltpeter, nodded with a smile, and led the army towards the north.

A hundred miles away from Liu Xuan's army, there is a lonely city, which is not too big, it can only be regarded as a small town, Liu Yi took the lead with an army of 300,000 to the city, and when Liu Xuan arrived, the two sides were in full swing, and there was a stalemate for a while.

In this ancient war, as long as the city gate is not broken and the defenders are loyal, it is indeed an extremely labor-intensive thing to take a city.

Now, there is not much left of Liu Xuan's army, the town here is called Gangzhou City, there are more than 400,000 defenders, Liu Yi sent the army to scold, and the city lord of Gangzhou City closed his door and held on.

Come to think of it, the Nine Shadows army marched west into Daluo, and they were invincible in a hundred battles along the way, although there were many of them, they did not dare to face the battle, and this is the reason.

Seeing the army under the city fighting and fighting for a long time, Liu Xuan retreated the army and sent troops forward to shout, "Anyone who surrenders will be let go, and those who do not obey will be killed!" ”

Liu Xuan knew that in ancient times, the two countries were at war, either you died or I died, which may also be the reason why this city could not be captured for a long time, and everyone was afraid of death.

"The emperor means this" Liu Yi was stunned in his heart, his face was puzzled, the two countries were at war, how could there be any surrender, in his mind, this might be the emperor's plan to delay the army, first trick them into surrendering, and then destroy them in one fell swoop.

Liu Xuan glared at Liu Yi and said, "Chrysostom Yuyan, if those who surrender don't kill, how can they break their promises." ”

Liu Yi was stunned, and his face changed greatly, "Your Majesty, if you really let go of these 400,000 troops, have you ever thought that they may rebel at any time, and it will also be a big hidden danger to our army." ”

As soon as these words came out, the generals also nodded.

The 400,000 Daluo standing army, that is all regular army, not 40,000, their Jiuyou army is only 600,000 now, where can they control the 400,000 army, in case the Daluo enemy army hits here, the 400,000 surrendered army is in a rebellion, they are not waiting for the end of annihilation.

Liu Xuan naturally thought of this, I believe that no army will let go of the 400,000 surrendered troops, no matter where they are put in, they are not a weak force, in case other Daluo troops come to support, these 400,000 troops are very likely to turn against each other, which reminds him of the story of the ancient Qin State Bai Qipit killing the 400,000 surrendered troops of the Zhao State.

The reason why there is such a decision, in addition to the low productivity and insufficient population in ancient times at that time, could not afford to raise the 400,000 army, more is that these 400,000 are the backbone of the Zhao State, if you don't kill, you may turn around at any time to kill the Qin State, in that era, I have to say that Bai Qi is also a generation of heroes, but the practice is also excessive.

Now, if it were him, he would really not do such a cruel thing, as a soldier, he would rather die in battle than kill 400,000 surrendered soldiers, this is humanitarian, not a beast.

In the city, the army looked at the 600,000 army of Jiuyou and did not mean to send troops, but just sent a herald to shout under the city to surrender and not kill, there is the emperor's holy purpose.

There is an emperor, more true than any words, the emperor has always been golden, never tell lies, even if they don't believe it very much, but watching the 600,000 army surround the town, it is only a matter of time before they want to break the city.

After a long stalemate, in the end, the city lord of Gangshu City personally went out of the city gate with a few guards and chose to surrender.

Liu Xuan immediately issued an order, all soldiers and horses entered the city, not to burn, kill and loot, violators of the order, killed.

The knives and weapons of the Da Luo army were confiscated, and Liu Xuan did not settle the surrender army, so he put several Da Luo officers under house arrest, and other officials were removed one after another and replaced with Jiuyou's army.

The people in the city were in danger and closed the door, and when the Jiuyou soldiers arrived in the city, they really stuck to their duties and did not have the slightest transgression.

Yu Fan, the city lord of Gangzhou City, saw this scene, his heart was relieved, and he admired the Emperor of Jiuyou.

Originally, he was ready to defend the city gate, but it was a big deal that the fish died and the net was broken, even in the end, he would have to bring the Nine Shadows army with him, but thinking of the millions of ordinary people in the city, he chose to gamble and open the city gate.

And Liu Xuan was not idle, after arranging everything, he went straight to the weapon shop, carved a vacant lot there, recruited the city's forgers, craftsmen, and began to collect sulfur in the city, as well as charcoal, plus the saltpeter he brought, to develop gunpowder.

As long as the gunpowder is developed, there is nothing he can't take