The Xianbei people attacked the city twice in a row, but they were fiercely returned by the defenders in the city, which made Cheng Lugui and Micah realize the seriousness of the problem.

If they retreat empty-handed because Baishan City is difficult to attack, the faces of the two of them will obviously have nowhere to put them, and they will not be able to explain to Lord Sully and the various tribes after they go back. However, if this kind of strong attack continues at any cost, more tribal warriors will die under the fortified city, and the time may not be able to break through the city.

The Han people are too cunning and cruel, they will only hide behind the cold and tall ice city walls and put cold arrows and stab cold guns, and they don't dare to go out of the city to fight in a dignified manner, so even if the warriors of the tribe have great strength and good riding skills, they will not be able to exert themselves here at all.

After some discussion, Cheng Lugui and Micah decided to temporarily suspend the siege of the city, and on the one hand, they sent messengers to the west to contact Kobineng to see if they could get support from Kobineng's side, and on the other hand, they sent people to report to Suri and ask for logistical support to prepare for a long siege.

In the view of Cheng Lugui and Micah, although the ice of Baishan City is strong, it cannot last, and when the spring warms up next year, the upper half of the city wall will melt and collapse, and the defenders will have no danger to defend, and it will be much easier to attack Baishan City.

The Xianbei people outside the city stopped attacking, and the defenders in the city were not in a hurry, they still closed the four gates, regularly poured water from the city every day, and continued to put a thick ice armor on Baishan City.

There are many sturdy underground warehouses built inside Baishan City, which are enough to store enough grain and forage for tens of thousands of soldiers and horses. Five large wells with a depth of 50 zhang were dug to draw drinking water from the underground diving layer, and a large number of "black stones" specially used for heating and boiling water for cooking were stored, and various consumable weapons and oil were stored...... In short, from the beginning of the design and construction of Baishan City, it was based on the most difficult situation, so that the defenders in the city could hold on to this lonely city for more than a year!

Zhao Yun knew that Zhang He and Sun Li were still on their way to the scheduled interception line, and in order to interfere with the Xianbei people outside the city and make them have no time to look around, Zhao Yun led his army out of the city several times at night to attack the Xianbei people's camp. Every time, I was dizzy about Cheng Lu Gui and Mika. But he always couldn't contain Zhao Yun.

In this era of backward information transmission, the Xianbei people in the east still don't know that the main general of the defense in the city is their natural enemy nemesis Zhao Yun, if the Xianbei people know about this situation, I am afraid they will quickly withdraw with the team without saying a word.

The name of Zhao Yun. Now it is better than the original White Horse Yicong leader Gongsun Zhan. Among the Xianbei people, it is synonymous with demons.

There is no fighting in Baishan City for the time being. Kebineng, who occupies the northern part of Bingzhou, has raised enough hatred for Liu He, and is now preparing to attack Youzhou in full swing. Presumably, it won't be long before the army of the Xianbei people will approach the western front of Youzhou. When the time comes, there will be another battle, and many people will lose their lives because of it.

Liu He took a generous gift to Juyong County, and then soon returned to the Western Front with 5,000 cavalry supported by the Wuhuan tribe in Shanggu. After these Wuhuan cavalry arrived on the Western Front, they were unified under the command of Xiahou Lan, the deputy general of the Xiao Cavalry Guard and the director of the Department of Internal Affairs, and their duty was to divide into 5,000 troops and roam on the defense line between the six cities of Banshi, Beipingyi, Gaoliu, Macheng, Ningxian and Quang Ninh, so as to supplement the ability of mobile combat for the Youzhou infantry defending the city.

After Liu He returned to Macheng from Juyong County, he called Guo Jia and Tian Chou to a secret experimental site set up by the Ordnance Division in the Macheng Branch, and then in front of two subordinates, he lit a black rope on the ground with a strange face, and saw that the rope was emitting smoke, like a burning earth dragon, quickly extending forward, until it rushed into a large iron urn that was buckled upside down in the distance.

When Guo Jia saw this, he felt a little bored, so he wanted to speak, but suddenly felt a vibration under his feet, followed by a loud noise, and then he saw the big iron urn weighing two hundred pounds in the distance being lifted up, rushing upwards four or five feet high, and then slamming into the ground again.

Tian Chou's throat tightened when he saw it, and suddenly remembered that when Gongzi returned from the secret field of the Weapons Division a few days ago, he always looked disgraced.

Liu He let go of the hand covering his ears at this time, and said with a smug look on his face: "How is it?" This is a welcome gift that I have carefully prepared for Kebi! ”

Guo Jia ignored his ears that were so shocked that he ran to the place where the big iron urn was placed just now, looked at the scorched black ground, shook his head and said: "Kebi Neng is not a stupid person, how can you let you bury this powder under his feet." ”

Liu He agreed with Guo Jia's analysis, but still said confidently: "What I put in the big iron urn just now was only twenty catties of black powder, if I buried two thousand catties of black powder on the top of Danhan Mountain, do you think Kebi can be sent to the sky by me at that time?" ”

"Black powder?" Guo Jia and Tian Chou spoke at the same time, but they were the most nervous and vigilant about the new word that appeared in Liu He's mouth.

Seeing Guo Jia and Tian Chou's stunned expressions, Liu He remembered that the name of black powder seemed to be circulated until later generations, and did not appear in the late Han Dynasty.

China was the first country to invent gunpowder, and black gunpowder officially appeared in the late Tang Dynasty. Gunpowder was invented by ancient alchemists, from the Warring States period to the early Han Dynasty, the emperors and nobles were intoxicated with the illusion of immortality, driving some monks and Taoists to refine the "elixir", and gradually discovered that saltpeter, sulfur and charcoal powder are easy to deflagrate or even explode after mixing in the refining process. In the late Tang Dynasty, the Tang Dynasty alchemist Qing Xuzi wrote the "Taishang Shengzu Jindan Secret", in which the "Fu Huo Alum Method" is the world's earliest written record of gunpowder.

Why was the flammable and explosive black powder called "medicine" by the ancients? This is because its main ingredients saltpeter and sulfur are important medicinal materials used in ancient Chinese medicine to treat diseases, and gunpowder was also listed as a medicine to treat dampness, avoid plague and treat skin diseases after its invention, and more importantly, the invention of gunpowder came from the practice of alchemy medicine for a long time, so it is called gunpowder.

Liu He patiently described the potential use of black powder in the military field to Guo Jia and Tian Chou, although it was not as exaggerated as mentioning bullets and cannons. But it also lifted the curtain on the use of gunpowder in warfare.

After Guo Jia and Tian Chou listened to Liu He's explanation, cold sweat began to seep out of their foreheads. The scene of the big iron urn being shaken up after the loud bang just now has been imprinted in the minds of the two of them, if this is just the effect of twenty catties of black powder, then two thousand catties of black powder is a hundred times more powerful, that kind of terrible scene, I'm afraid that no one in this world can resist.

Tian Chou asked cautiously: "Presumably, this black powder is the great killing weapon created by Gongzi during this time, right?" ”

Liu He nodded and said proudly: "Yes, in order to make up this thing, this son is taking a great risk!" ”

Guo Jia heard this. Suddenly his face sank. He said a little excitedly: "Childe, how can you risk your life so much!" A gentleman is not a weapon, even if you don't have this kind of black powder with amazing explosive power, as long as you stick to your own ideals. Who in the world will be able to stop you in the future? ”

Guo Jia scolded Liu He in person. Tian Chou on the side also had a heavy face. did not say anything to stop it, and it seemed that Guo Jia's opinion was also supportive, but he was out of consideration for the sake of protecting Liu He's face. did not follow Guo Jia to criticize Liu He.

Liu He was speechless by Guo Jia's words, and he wanted to refute a few words, but when the words came to his mouth, he swallowed them back.

From Guo Jia's point of view, Liu He's disregard for his personal safety to tinker with these tricks is indeed not stable enough. No matter how powerful the black powder is, it is not as important as Liu He's life, and now Youzhou and Jizhou can lack anyone, but Liu He cannot be missing, as long as Liu He continues to fight steadily, ten or twenty years later, the unification of the Han is basically foreseeable. But if Liu He was killed because of such an extremely dangerous thing as black powder, the political group headed by Liu He would lose its backbone and direction, and even Guo Jia, who was extremely resourceful, would not dare to imagine where Youzhou and Jizhou would go without Liu He......

Liu He adjusted his mood and said solemnly to Guo Jia: "Fengxiao don't be angry again, I promise you, if you don't make an example, there will never be such a thing in the future." ”

Guo Jia refused to stop there, and asked: "There is no evidence, some whimsical ideas often pop up in the mind of the child, in the future, if Zitai and I are not supervised by your side, and you sprout in a solid state, you can't help but mess with those dangerous things, what should I do?" ”

Liu He was a little speechless by Guo Jia's "Erlengzi" spirit of daring to be more serious with his boss, he pouted and said: "My son has already promised, so what else do you say?" ”

Guo Jia was also out of the way today, regardless of whether Liu He was happy or not, he said stiffly: "Please write a letter of guarantee as a certificate and hand it over to me and Zitai for safekeeping." ”

Liu He's head was big for a while, and he asked Tian Chou: "Zitai also means this?" ”

Tian Chou lowered his head, didn't look at Liu He's eyes for help, and whispered: "Feng Xiao did this out of consideration for the safety of his son......

Liu He had no choice but to ask someone to bring paper and pen and write a "letter of guarantee" that from now on, he would not participate in the research and development of any danger tests.

Guo Jia carefully put the guarantee in his arms, and then said: "The black powder developed by Gongzi is incomparably powerful, and it can be described as the first killing weapon in Youzhou, so it must not be easily revealed, let alone let people master the recipe for making black powder." The subordinates suggested that a separate secret gunpowder bureau be set up under the Weapons Division, in which all personnel must be isolated from the outside world and under the direct supervision of Childe. ”

Liu He said a little angrily: "Just now someone was still forcing me to write a letter of guarantee, which will make me directly supervise the Gunpowder Bureau, can I have a bottom line and discipline as a person?" ”

Guo Jia turned a deaf ear to Liu He's complaints and continued: "Because the formula of black powder is too important, even Zitai and I must also avoid it to minimize the links that may leak secrets. ”

Liu He listened for a while, he quickly interrupted Guo Jia's chatter, and said: "The matter of setting up the Gunpowder Bureau, let's talk about it later, now let's study how to use black powder to deal with Kebineng!" ”

Tian Chou said with some emotion: "There is a way to 'capture the thief and capture the king first', if you can lure Kebineng to the place where the black powder was buried in advance, and then wait for the opportunity to detonate the black powder buried in the ground, not only can Kebineng be shocked to death, maybe even some important tribal leaders around him can be solved together!" ”

Guo Jia asked, "How long does it take to make two thousand catties of black powder?" ”

Liu He replied: "As long as the materials are sufficient and mixed according to the formula, two thousand catties can be made within three days." ”

"Do you have plenty of materials in Horse City?" Guo Jia asked again.

"Feng Xiaoke remembers that a few years ago, I handed over a list to the Ordnance Department and the Captain's Mansion, which listed some herbs and stone powder that needed to be purchased in large quantities from other states? In fact, there are materials for making black powder. ”

Guo Jia nodded, remembering that Liu He had inadvertently explained this matter at that time.

"Recently, I asked Liu Fang to count the various reserves in the medicinal material warehouse, and it is not a problem to make two thousand catties of black powder."

"Good! Since the mass production of black powder is not a problem, there is a plan for the subordinates here, maybe they can blow up Kebi into powder! (To be continued......)