Father can be an enemy to the country

After leaving Zunhua, marching became difficult. Because we entered the Yanshan Mountains.

If viewed from a high place, the majestic and steep Yanshan Mountains look like a tall and solid city wall, standing at the northern end of the North China Plain.

For the army of this era, the entire Yanshan Mountains was almost impossible to traverse, and only a few tunnels formed by river erosion could allow vehicles and horses to pass through. There are only five such tunnels in total, and five indestructible passes were built by the Central Plains Dynasty.

The Central Plains Dynasty also built the Great Wall in the Yanshan Mountains, making the Yanshan Mountains increasingly insurmountable. Cut off the northern nomads from the Han world. The Song Dynasty was obsessed with recapturing the Yanyun Sixteenth Prefecture, in fact, it was just to recapture this natural danger.

However, when the Central Plains Dynasty was preparing for the northern expedition to the grasslands, this natural danger would also seriously hinder their progress.

Now it was the turn of Zhu Zhen and his army, with a total number of nearly 400,000, to experience the difficulty of the Yanshan Mountain Road.

Ice rows are definitely out of use in a place like this. All the grain and grass must be pulled by horse-drawn carriages, pushed by wheelbarrows, and carried by shoulder poles. Although Xu Da spent great efforts to improve this road when he rebuilt the Yanyun fortifications, so many vehicles and horses poured into this narrow mountain road, which was also covered with ice and snow. As long as a car lost a wheel or got stuck in a pit, , the entire road will be blocked with water in an instant.

Although Zhu Zhen and the others are princes, they are still stuck in a place like this and have no temper at all.

Seeing that there was no movement for half an hour, they dismounted and looked up the mountain.

"Good guy, let's not forget that we were stuck in traffic for five miles." Lao Twelve put away the telescope and said with a wry smile: "I'll be thankful if I can walk twenty miles today."

"It's normal." Zhu Fan said as he had become accustomed to it: "When we came from Xuanda University, there were only 100,000 of us, and there were a lot of traffic jams along the way."

"This is what marching in winter is like." Zhu Di said with a very understanding look: "Especially when it snows, the road is slippery and the potholes are invisible. It's really annoying."

"It seems that the history books say that sending troops in the spring is reasonable." Old Eleven said.

"That depends on the score." Zhu Di shook his head and said: "Like us this time, we have to leave early. Otherwise, when the snow melts next month and enters the return period, there will be no way to leave. We will return in another month The pulp period is over and Naha has already returned to the Northeast. Why don’t we fight?”

"Third brother, what's going on during the recuperation period?" Lao Twelve curiously asked Lao San beside him.

"Ask your fourth brother." The third child kicked the ball to the fourth child. "He is now an authentic old Peiping."

"It's not a problem for me." Zhu Di replied happily: "It's the mud-returning period, when the ground is turned over in spring, and the road is covered with mud. It's so bad that you can't pull it out even if you step in it."

"Ah? Why?" Even Old Eleven was curious now.

"I don't know why, it must have thawed." The fourth child said at a loss for words, "Ask your teacher, he knows everything."

"Ha, Fourth Brother really couldn't fail me." Lao Liu really gave the explanation: "This is due to the cold winter. Under the action of condensation and diffusion, the water in the underground constantly moves upward and accumulates under the surface. Freezing. In early spring, the temperature begins to rise, and the frozen soil layer melts from top to bottom. Before the lower layer melts, the melted water in the upper layer cannot penetrate, thus forming slurry water. Once the water and soil mix, it will become mud. Yet?"

"Look, what is erudition?" Zhu Di smiled and gave a thumbs up.

"That's it..." Eleven Twelve suddenly realized: "It's so difficult to walk now. If this is the relapse period, we won't be able to get on the road."

"That's not the case, so we have to complete the first phase of the combat mission before the return period." Zhu Zhen nodded and said, "The time is actually still very tight."

"It's such a difficult road, can we get there on time?" Lao Twelve was very worried.

"Nonsense, you can all think of this question. Couldn't the general and Duke Ying have thought of it when they made the battle plan?" Lao Si laughed and scolded: "Xifengkou is the shortest road to the outside of the Great Wall. After leaving the customs, It takes a few days to reach Daning.”

"Listening to Fourth Brother's words, I thought of an allusion." Old Eleven said: "In the second year of Zhihe in the Northern Song Dynasty, Liu Chang was ordered to envoy to Liao. In order to prevent the envoy from Song from knowing the route out of the customs, he would not be exploited in the event of a war between Song and Liao. "The Khitans deliberately took him out of Gubei Pass and took many detours to show how long and difficult the journey was."

"Unexpectedly, Liu Chang knew the roads to the north very well, so he asked the other party: 'There is obviously a straight road to go, and it is only more than ten miles from Songting Pass to Zhongjing. It can be reached in just a few days, so why did you deliberately take the long way?'

"The Khitan had no choice but to admit his mistake. When asked how he knew, he said: 'Because this is the land of my Han family. When Cao Cao conquered Wuhuan, he took this road.'" After a pause, Lao Shiyi was afraid. The brothers didn't understand, so they explained: "The Songting Pass that Liu Chang mentioned is the current Xifengkou. It was called Lulongsai in the Han Dynasty."

"There is no need to explain it so clearly." Zhu Di, the only student present, knew that this was probably explained to him, and said angrily: "Lulongsai is Xifengkou, Xifengkou is Songting Pass, such a famous place, I still know."

"It's a pity that people in the Song Dynasty can only live with their mouths." After hearing this, the third child laughed and said: "Unlike us, we can really go out to fight the Tatars!"

"Yes, fortunately the general recaptured Youyan, otherwise the Ming Dynasty would not have been able to fight out of the fortress." The brothers were convinced.

At this time, the team finally started to move again, and they continued down the mountain.

~~

The army marched slowly on the narrow mountain road, stopping and starting. It took four days to complete the rugged and winding mountain road from Zunhua to Xifengkou.

In fact, Xifengkou is the Luanhe River Valley. After tens of millions of years, the surging river water has washed out a river valley several feet deep from the seemingly indestructible mountains. The relatively flat river valley has become a passage in and out of Yanshan Mountain, and has been a battleground for military strategists since ancient times.

In order to control this river valley military road, checkpoints have been built here since the Han Dynasty. However, the current pass was rebuilt by Xu Da, so it looks brand new and indestructible, just like the Ming Dynasty today!

Standing at the foot of the pass, looking up at the five-foot-high Xifengkou Pass, Zhu Gang couldn't help chanting: "I suddenly screamed while touching my pillow at three o'clock in the morning. I dreamed of taking Songting Pass. The opportunity to win the Central Plains has been lost repeatedly. I will shed tears on the bed tomorrow."

"Is this a poem you wrote?" asked the fourth brother.

"It's Lu Fangweng, idiot." The third brother shook his head helplessly and rode up to the city gate.

"I was wondering why it was so sad, sighing and crying." The fourth brother scratched his head and followed him in.