Du He's words moved Li Shimin.

Du He's analysis of the Qin State is quite thorough, and he thinks the same in his heart.

During the Warring States Period, the siege equipment at that time was not perfect, so the natural danger of the Qin State had never been breached, and even the alliance of the Six Nations had nothing to do in the face of the natural danger of the Qin State.

In addition to developing its national strength with the help of natural risks, the Qin State sent troops from time to time to take advantage of it, just like Du He said, only the qualification to beat people, and there was no possibility of being beaten.

However, the six eastern countries are interconnected because of their territory and no natural dangers, so they are fighting and intriguing. After the development of successive monarchs, the national strength of Qin Shi Huang's generation has surpassed the comprehensive strength of the six countries. Therefore, for Du He's sentence that the Qin State unified the world is the trend of the times, and there is no attitude of opposition.

If Tibet is really like the Qin State, then the problem is quite serious.

Like the Qin State, Tubo will continue to gather strength and become stronger and stronger, and it is not impossible to even catch up with the Tang Dynasty.

It's just that Li Shimin doesn't understand that the natural danger of Qin is Hangu Pass, and it is the dangerous road of Bashu, so what natural danger can Tubo defend?

Li Shimin asked the question in his heart: "Tubo is not familiar with it, but I also know that Tubo does not have such natural dangers as Hangu Pass, how can it be compared with the Qin State during the Warring States Period?" ”

"Indeed...... It is true that there is no dangerous natural danger in Tibet, but their climate is a chasm that is more difficult to cross than natural danger for us Central Plains people! This climate of theirs, I gave it a name, is called altitude sickness. Du He's face was serious, and no one knew better than him how great the impact of altitude sickness on ancient people was. Even in modern times, this altitude sickness is still not well controlled. Even if the military quality is as strong as that of the PLA troops, it will not work.

He knew that this altitude sickness was knowledge beyond the times, and even if Li Shimin was smart, he might not be able to understand it for a while, so he explained it in great detail.

"This altitude sickness is a natural physiological reaction of the body after reaching a certain altitude because it does not adapt to the changes in air pressure, lack of oxygen, and dry air caused by altitude."

Based on his only knowledge, he introduced this altitude sickness to Li Shimin.

Du He was also secretly glad at this moment that he had traveled to Tibet Province in later generations, and when he entered Tibet, the tour guide had introduced the knowledge of altitude sickness in detail.

If it weren't for that, he wouldn't be able to explain it to Li Shimin at this moment.

Li Shimin was a little dizzy by Du He's set of knowledge theories, but he also roughly understood what Du He said.

"Don't make things so complicated, I really don't understand something. To put it simply, it is not used to the water and soil, just like the southerners are not used to the cold of the north, and the northerners are not used to the heat of the south? As soon as our Central Plains people go to Tibet, they will cause a series of symptoms such as pain, palpitation, shortness of breath, loss of appetite, fatigue, fatigue, dizziness, nausea, vomiting, abdominal distention, diarrhea, chest tightness and pain, insomnia, dizziness, drowsiness, dizziness, numbness of hands and feet, convulsions, etc. So that the morale is broken, and the inability to fight? ”

"Uncle Li Shengming!" Du He nodded and emphasized again: "The terrain in Tubo is different from ours, they live on a plateau that is more than two or three thousand zhang high. Therefore, this soil and water discomfort is much more serious than that of us southerners going to the north, or northerners going to the south! ”

He said three "more" in one breath to indicate the seriousness of the situation.

Because he knew that the Tang Dynasty's estimation of the plateau climate was seriously underestimated, and there were four major defeats in the battles between the Tang Dynasty and Tubo over the years, namely the Battle of Dafeichuan, the Battle of Qinghai, the Battle of Surohan Mountain, and the Battle of Yinzhijia River.

The Battle of Dafeichuan, the Tang Dynasty's 100,000 troops were all annihilated; In the Battle of Qinghai, the 180,000 Tang Army was almost wiped out, in the Battle of Surohan Mountain, the more than 100,000 Tang Army was defeated, and in the Battle of Yinshujiahe, the 200,000 Tang Army was annihilated.

It is worth mentioning that these places are located on the Qinghai-Tibet Plateau, although the strength of Tibet was also one of the reasons for the defeat of the Tang army, but the existence of the plateau climate was indeed a nightmare for the Tang army.

In general, in the battle between the Tang Dynasty and Tubo, the Tang Dynasty won more and lost less, but because of the plateau climate, it was difficult for them to achieve excellent results.

So, now that Duhe has traveled to this era, he must stop this from happening.

Li Shimin glanced at Du He deeply and said, "Since you said that altitude sickness is very harmful to our Central Plains people, what about Tibet?" Won't they feel unaccustomed to the water and soil when they go down to the plateau? ”

Duhe replied, "Yes! But it's not too harmful! That's why I say that Tibet is like Qin, it's hard for us to attack, but they can be easily killed. There is no natural risk, and it is better than natural risk. Let's take an example, if a team of 10,000 people in my Tang Dynasty arrives in Tibet, at least thirty percent of them will get sick without fighting, and the remaining seventy percent will only have fifty or sixty percent of their combat strength left. And the 10,000-strong team of people in Tubo who came to our Datang and fell ill because of it was no more than five or six hundred, but they were still able to maintain seventy or eighty percent of their combat effectiveness. ”

Li Shimin lowered his head and pondered, if it is really as Du He said, then Tubo will inevitably become a fierce rival of the Tang Dynasty in the future, but it is just ......

Li Shimin's suspicious gaze swept over Du He, "Where did you learn about this?" I believe that few people in the entire Datang know about these things. ”

In response to Li Shimin's question, Du He has already filed for the record. He was only fifteen years old and had a lot of experience, so without a reasonable explanation, it would be difficult for Li Shimin to believe his words.

Du He didn't hesitate, and said calmly: "This is what my master told me!" ”

"Your master?" Li Shimin looked at Du He directly and asked, he had never heard that Du He had a master.

"I won't hide it from you! In fact, I have met a strange person since I was a child, his name is Chu Liuxiang, he is a ranger, and it is not an exaggeration to call his martial arts the first in the world. By chance, we bumped into each other, and he saw that I was a genius in martial arts. So he accepted me as an apprentice, but he also told me that his martial arts were supreme. If I can practice to the highest level, I can be a hundred, but before I become a small success, I must not leak half a point, so as not to be detected by the bad guys, which is not good for me. He has traveled all over the world, and he told me about the customs and customs of various countries! Of course, the same is true for Tibet. If Uncle Li really doesn't believe it, he can arrange for 100 people to go to Tubo to try the truth. Du He's face did not change and his heart did not beat.

Li Shimin couldn't tell whether what Du He said was true or false, but he also knew that there were countless strange people in the world, and it was not strange to have a Chu Liuxiang.

Du He looked at Li Shimin and raised his voice: "The sky is proof, if I, Du He, have half a false sentence about Tubo, I am willing to suffer the punishment of thousands of knives and thousands of arrows through my heart." ”

Li Shimin shook his head and said, "It's not necessary to be such a virtuous nephew!" It's not that I don't believe you, it's just that this matter is very important, and what Wuji said is not unreasonable, so I have to think about it! ”

Hearing the word "Wuji", Du He's eyes showed a hint of abruptness, and also showed a slight sneer: "Eldest grandson old fox, the master is not finished with you!" ”

While Li Shimin was pondering, Du He took out the clothes he had stripped off from Lu Dongzan's body and said, "Uncle Li, there is still something for you to show here, little nephew." ”

ps: The battle between Tubo and the Tang Dynasty is interspersed with almost the entire Tang Dynasty, and it is also popular to face the Tubo Datang with more defeats and fewer victories, but it should be a fallacy.

In the Tang Dynasty, a historical emperor found out 88 victories of the Tang Dynasty against Tubo from the "Zizhi Tongjian", and the record of Tubo's victory over the Tang Dynasty did not exceed 40 battles, and each side had great victories and defeats.

But almost all of the great defeats of the Tang Dynasty were on the plateau, and it is not an exaggeration to say that the plateau climate was a nightmare for the Tang Dynasty.