Li Shimin guarded the Tongguan Pass.

Ever since he led his troops to force Yao Ping back, he has been leading people to garrison this place. After all, Tongguan is in a critical position, and it may even endanger the peril of Chang'an, although the situation is not good, but there is no other way.

Although Li Shimin only received orders from Li Yuan to guard the town, he was not idle. He is always paying attention to the movements in the direction of Luoyang, if he is not prepared at all, wouldn't he kill himself?

Although the scouts under his command are not as powerful as the Snapdragon Army, they can also detect a lot of things. It is precisely because of the support of intelligence that Li Shimin has enough confidence.

In addition, some time ago, Li Yuan had some mysterious things transported from Chang'an. From the will brought by the messenger, Li Shimin knew that this thing was called thunder punishment.

Li Shimin naturally knew about Yangzhou's martial arts, after all, the stakes in this battle were too important. It was also since then that Yang Guangcai fell into complete defeat and was killed by Yu Wenhua.

"I can't imagine that this thing looks ordinary, but it has such amazing power, it's really incredible!" Li Shimin sighed inexplicably, he knew very well the importance of lightning punishment.

As time passes, it won't take long for the Yanyun army to reach Tongguan. This thunder penalty is extremely powerful, and the momentum is amazing, and if it can be used properly, it will certainly have a miraculous effect.

But from Li Yuan's additional secret letter to Li Shimin, he knew that the use of this thunder punishment was still limited. However, this has little impact, and the existence of lightning punishment is a great deterrent.

In fact, Li Yuan didn't think about letting Li Shimin completely block Yanyun's enemy army from Tongguan. After all, the enemy's strength was so strong that even Li Yuan himself was shocked when he heard it.

As long as Li Shimin can block Yanyun's army outside Tongguan for a period of time, and then consume its strength as much as possible, it will be good news for Li Yuan.

Li Shimin is also sitting with this plan, he will not risk his life to fight Luo Cheng to the death here. It is also necessary and understandable to protect oneself appropriately.

At this moment, Li Shimin suddenly got the news that Luo Cheng had led the army to Luoyang. I'm afraid it won't take long to enter Tongguan, and when he learned of this, Li Shimin's expression suddenly changed greatly.

It is precisely because Li Shimin knows Luo Cheng quite well that he is extremely jealous of him. In the face of Luo Cheng and Yan Yun's thousands of troops, Li Shimin's heart had already risen to retreat.

But Li Shimin is not completely calm, he can evacuate Tongguan and leave. But this is based on the premise that he accomplishes his strategic goals, otherwise he will not show his intentions.

After hearing the news, Li Shimin's expression became extremely solemn, and he said to himself: "I didn't expect that Yanyun's army would arrive in Luoyang so soon, it seems that a big battle is already inevitable." ”

"This batch of thunder punishments sent by my father seems to be extraordinarily powerful, you can try to start from here, if nothing else, it should be able to restrain the enemy's advance." Li Shimin quickly thought about the important matter.

It's a pity that there is no figure like Li Jing in the army at this moment, and Li Shimin has no one else to discuss when considering tactics. Yanyun's army is famous, and ordinary people are discolored when they hear it, how dare they fight with it?

That is, Li Shimin has no other way out, so he can only rack his brains to delay time as much as possible. Otherwise, Li Yuan's arrangement, and even the survival of the entire Li family, are closely related to it.

After some consideration, Li Shimin quickly had an idea, he had to make arrangements for this batch of thunder punishments before Luo Cheng arrived, and at the same time achieve the goal to the greatest extent.

Yan Yun's army of 300,000 people relied on this batch of thunder punishments to kill and injure on a large scale. But with this thing, it is still possible to hit the morale of the enemy army and the offensive to a certain extent.

In Li Shimin's view, in this era of cold weapons, the sudden appearance of hot weapons will inevitably cause great repercussions. After all, if this thing is released, it will be like a thunderbolt punishment from the sky.

It's just that Li Shimin didn't take into account that Luo Cheng not only knew the existence of gunpowder, but also knew its formula, and also developed more powerful attack methods, and was also ready to use it to make a wave of Chang'an.

The disparity in the intelligence work of the two sides can be seen.

After thinking about it, Li Shimin no longer delayed, which made people keep an eye on the movements of Yanyun's army at all times. At the same time, people are always ready to bury the lightning penalty when the enemy approaches.

……

There is no doubt that during this time, Li Shimin thought about it a lot.

But Luo Cheng is not a person who is easy to take lightly, since he has chosen a large group. Then he is bound to do things perfectly, and if there is too much disclosure, it will inevitably run counter to his ideas.

These 300,000 troops were all brought out by him from Yanyun, and Luo Cheng knew very well that the two sides were fighting, and it was impossible for them to be free of casualties. But since he is the commander of the three armies, he naturally has to avoid losses as much as possible.

After learning that Li Yuan might have also obtained the formula for gunpowder, Luo Cheng was not too surprised. This thing would have appeared in the first place, but it was just a little earlier because of his existence.

can rely on the original formula of black powder in Li Yuan's hand, and if he wants to deal with them, he will inevitably be too contemptuous. Luo Cheng is also a traverser and knows more things.

This time, Luo Cheng has carefully improved a wave, and even brought big things such as catapults. Presumably, when Li Yuan saw this, his expression must have been very exciting.

After the army rested for a while in Luoyang City, Luo Cheng set off without delaying too long. He already knew the news through Yao Ping, and the next thing to see was the specific battle.

So, excluding the troops left behind in Luoyang, Yao Ping led 30,000 Snapdragon troops to participate in the war, which was still 300,000 soldiers and horses. Reasonable transport routes have long been formed along the way, which are enough to ensure the stability of the war.

"The guard in Tongguan is Li Shimin, who is extremely intelligent and should not be underestimated. But fortunately, Ben Shuai had already made people ready, and it didn't take long to break through Tongguan. Luo Cheng said firmly.

It's not that Luo Cheng is too proud, he is prepared for what is happening at this moment. As long as Li Shimin didn't see the clues, it wouldn't take much effort to take Tongguan, and the catapult was also prepared for this.

The generals obviously have a lot of trust in Luo Cheng, and what has happened over the years has allowed Luo Cheng to accumulate considerable prestige in the army, and with him as the commander of the three armies, some things are vividly displayed.

With a slight sweep of his eyes, Luo Cheng continued: "According to the news from the scout's investigation, we can know that Li Yuan may have obtained the formula for gunpowder, and now that he should have a finished product, maybe this Tongguan is planning this matter." ”

"The power of gunpowder is not small, if it is not careful, it may cause great casualties, it must not be taken lightly, and it is necessary to prepare in advance, after all, Li Shimin will definitely not sit still."

Luo Cheng said in a resolute tone and unusually firmly.