The preparation of the powder keg is to emulate the mines, Ma Sanbao did not know the method of making mines, in his time, mines no longer belong to the category of humanitarianism, this kind of weapon is not to say that it can be used, but he still understands the principle of simple powder keg mines, after all, in the Three Kingdoms period, there was a precedent.

The city not far away is an extremely important strategic location, both the Ming and the Northern Yuan did not want this city to fall into the hands of the enemy, the Mongol soldiers resisted stubbornly in order to keep the last pure land to the Northern Yuan, just after the leak of the revolver technology of the Northern Yuan, they understood that it would become particularly difficult to grab strategic resources from the Han people of the Ming Dynasty.

"What? His Majesty actually wants to send Lan Yu to the Northeast Theater? Xu Da's eyes widened, he and Lan Yu and others were quite influential, after all, Lan Yu and Hu Weiyong were close before, and they can be said to be Hu Weiyong's good brothers, just like the relationship between Liu Bei and Guan Yu at the beginning, but he Xu Da never thought about rebellion, and Lan Yu and others are not the same kind of people, don't look at Lan Yu has made fruitful achievements for Daming, no one knows whether Lan Yu will temporarily rebel and go against Daming.

Lan Yu is coming to the battlefield and will definitely take over Xu Da as the commander, as far as Xu Da's current situation is concerned, Xu Da's leg is injured, and he basically can't go to the battlefield as a first-mover general, as for Ma Sanbao, he can only be isolated now to do remote command.

The powder keg was successfully made and sent to Ma Sanbao, the powder keg in front of him had never even seen Ma Sanbao, but he knew that once this explosion started, there would be heavy casualties, he looked at the powder keg in front of him very carefully, if this thing exploded in front of him, he would go to see Lord Yama immediately, maybe let a few soldiers accompany him.

Whether it is Ma Sanbao or the soldiers, they are very cautious looking at the powder keg in front of them, the principle of the powder keg Ma Sanbao is also clear, and the concept is also provided by Ma Sanbao, if this powerful powder keg explodes in the military camp of the Northern Yuan Dynasty, it is definitely a great joy, but this is the military camp of the Ming Dynasty, and no one wants this thing full of gunpowder to be like fireworks in the military camp of the Ming Dynasty.

"Arrange it in advance, no one will enter my barracks again, there are about three days left, I'm afraid you will be infected." Ma Sanbao said helplessly, most diseases have an incubation period, and he is afraid that the soldiers of the Ming Dynasty will be infected because of this.

Now that Ma Sanbao is talking about it, he is wearing a simple mask, the mask is imitated by him according to the memory of his previous life, whether it can work or not, at least there is a self-satisfying effect, after such a long time, there is no problem, he has long understood that he is not actually sick, but he is nervous and scares himself.

Outside the city, there is a steep ramp, the ramp is the last line of defense of the Northern Yuan, since the exposure of the revolver technology, the Ming Dynasty has been advancing all the way, and the Northern Yuan army is constantly retreating, of course, the advance of the Ming Dynasty has also paid the price of blood, compared with the battlefield in the south, the battlefield in the north will produce heavy casualties even for a city, the remnants of the Great Yuan in the south and the orthodoxy of the Northern Yuan in the north are not of an order of magnitude at all, don't look at the background of the Northern Yuan Dynasty can not compare with the Ming Dynasty, it is also the dynasty that dominated the Central Plains for a hundred years.

At night, Xu Da's barracks were brightly lit, most of the Ming soldiers chose to rest during the day and chose to act at night, these soldiers hid the powder keg and the lead without knowing it, if the two armies went to war, they only needed to shoot rockets to the fuse, and they could ignite the powder keg prepared earlier, they used binoculars to determine it, and the Northern Yuan did not find their actions.

"The little rabbit cubs of the Northern Yuan, wait for the baptism of our Daming!" Xu Da smiled, the plan is ready, just waiting to be implemented, once the plan can be successfully implemented, it will be a victory, they also understand that the terrain is basically impossible to attack without doing anything, that is the pure natural defense line of the Northern Yuan, the last hope of the Northern Yuan, once it is broken through by the Ming Dynasty, it means that the border city has fallen, and the Northern Yuan does not want this city to fall into the hands of the Ming Dynasty, otherwise so many battles will be sacrificed in vain during this time.

The Ming Dynasty also has the same idea, for that city, they are bound to win, if they can't take it, the blood shed before is in vain, no Han people of the Ming Dynasty are willing to sacrifice in vain, they are all sacrificing their lives for the country, for the faith in their hearts, for the Ming Dynasty, throwing their heads and spilling blood is not a problem at all.

"Brother Xian, have you slept? I tell you good news, the gunpowder has already been arranged. Zhu Di said outside Ma Sanbao's tent, in the past many days, Ma Sanbao was completely fine, Zhu Di naturally put his mind at ease, but Ma Sanbao was still cautious, the tragic experience of his previous life made him understand what it means to prevent problems before they happen, if there is an epidemic of disease in the Ming Dynasty, Ma Sanbao must be the one who knows how to protect and isolate himself the most.

"I just want to rest, I'm different from you, you don't notify me when you sleep during the day, don't let me go jet lag with you, now you have to squeak early in the Western Hemisphere!" Ma Sanbao protested with some dissatisfaction, he had been isolating himself all day, in addition to books, drawing drawings and writing down his Fujian development plan, who knew that the soldiers outside were asleep, and only the cooking class was still preparing meals on time.

"What is Western Hemisphere time?" Zhu Di was a little puzzled, he didn't know that the planet he lived on was called the earth, and the China he was in belonged to the eastern hemisphere, and the West belonged to the western hemisphere, after all, Copernicus had not overthrown the geocentric theory in this era, and for the people who lived in the Ming Dynasty, there was no so-called geocentric theory, they didn't know that the earth was round.

"It's just a metaphor, don't care about so many details, in layman's terms, it's a life that is a few hours away, and it's about the same as the time in the West." Ma Sanbao said, he stretched his waist and yawned, during this time, after returning to the barracks life, he felt that he had boiled out dark circles, you know, in Nanjing City and Beiping, he rested on time very much, and basically developed a habit, but when he arrived at the battlefield, the other soldiers did not sleep, even Zhu Di was not ready to rest, he couldn't rest alone, right? He is still the commander-in-chief of the battlefield, with him and without him, the outcome of the battle may have changed a lot, if he was there some time ago, in Xu Da's eyes, there may be fewer deaths.

"Your metaphor is always strange, you rest first, we are waiting to send a war letter to Beiyuan." Zhu Di opened his mouth and said, "You must lead the Northern Yuan to that mountain, otherwise you will prepare in vain." ”

"I'll give you a suggestion, don't deliberately choose a place, let Beiyuan choose, I believe that Beiyuan will definitely think that the mountain is easy to defend and difficult to attack, and choose that place, Your Highness, and General Xu mentioned it, we must let Beiyuan choose the battlefield, not us, we have pit Beiyuan many times before, Beiyuan will definitely take precautions, and have a heart." Ma Sanbao yawned and spoke, although the words were very vague, but Zhu Di did not dare to let go of any information, in Zhu Di's mind, Ma Sanbao's every sentence is like the Bible, although there are occasional flickering times, but the vast majority of them are absolutely loyal.