On the third day of the April 1st, Li Shimin took charge and became the marshal of the Longyou Road march, leading 20,000 troops to Tuyuhun.

On this day, Zhang Chao, the marching supervisor of the right rear army, also brought his three thousand eagle soldiers and escorted the civilian transport team to follow him.

The four passes in Guanzhong are the country of Tianfu.

Guanzhong has always been very dangerous, Tongguan, Wuguan, Xiaoguan, Sanguan, and the four passes guard the pass. There is the Yellow River in the east, the Qinling Mountains in the south, and the Longshan Mountains in the west.

After passing Longshan and leaving Longguan, it is Longyou.

The Longshan Mountains lie across the northwest of Guanzhong and are the northwest of Guanzhong. The main channels from Longshan to Guanzhong are the Wei River, Jing River and other rivers that pass through the lowlands of river valleys cut into.

The mountains in the direction of the Wei River are relatively steep, while the direction of the Jing River is relatively simple.

Xiaoguan stands at the Longshan Pass under the danger, guarding the passage from the direction of Jinghe River to Guanzhong.

Now Luo Yi leads tens of thousands of troops to guard this important northwest gate of Guanzhong.

Guanlong and Guanlong refer to Guanzhong and Longyou.

The highlands in northwest of Guanzhong are very important for the security of Guanzhong. The Xiaoguan guarded by Luo Yixi is focusing on guarding the Jinghe passage that is most likely to enter the Guanzhong Plain.

What Li Shimin was going to go was the Wei River line to the south.

Longzhou and Tianshui are sandwiched between Longshan and the east, standing on both sides of the west, controlling the road through Longshan along the Weishui River Valley.

In the fifteen divisions of the world that the court had just completed, Longzhou was classified into the inner road of Guanzhong, because Longzhou blocked the dangers at the bottom of Long, controlled Qin and Feng's conflict, and became an important city in Guanzhong.

But Tianshui was placed in Longyou Road.

The Great Zhen Pass became an important pass between Longzhou and Tianshui, and it was also an important boundary between the inner road of the pass and the Longyou road.

Zhang Chao once heard Fang Xuanling and others talk about the importance of Longyou. If you want to protect Guanzhong, you should first strengthen Longyou.

Guanzhong has a high-level view of the Central Plains, while Longxi has a high-level view of the Guanzhong.

Longxi occupied the upper reaches of Guanzhong, and even had the upper reaches of Hanzhong and Shuzhong. The river valley lowlands formed by Weishui, Qiang River, Western Han River and other rivers provide a connection between Longxi and Guanzhong, Hanzhong and Shuzhong. The terrain of Longxi is significantly higher than that of Guanzhong. Hanzhong and Shuzhong. It is difficult to attack Longxi from Guanzhong, Hanzhong and Shuzhong, but it is easy to attack from Longxi.

For this reason, it is very important to obtain Longxi. During the Three Kingdoms, Shu and Wei competed in Longxi, and later during the Southern and Northern Dynasties, the struggle for the Di people by Liu Song and Northern Wei was all due to this strategic idea.

Longxi is enough to control Guanzhong.

Li Shimin's rare defeat in his life happened in the battle with Xue Ju's father for Longyou. Li Shimin was defeated by Sumizuhara, and his pants were almost gone. Most of the eight general managers were captured. In the end, Liu Wenjing and others took the blame for him. In the end, the Tang army united Li Gui from Hexi and attacked Xi Qin on both sides to win.

At that time, the Li family first occupied Guanzhong, the Xue family occupied Longyou, and Li Gui occupied Hexi, and Guanlong competed for power. The Li family first lost consecutively, but later Tang and Liang jointly destroyed the Western Qin and eventually occupied Guanlong.

From the perspective of the entire military and geographical strategic perspective, Guanlong is located in a corner. The Guanzhong-based idea of ​​the Li Tang Dynasty was like the Han Dynasty. First stabilize Guanzhong, and then plotted against the Central Plains. You can attack and retreat and defend.

However, to ensure the safety of Guanzhong, we must first control the backyard of Longxi. To control Longxi, we must also control Hexi. To control Hexi and pacify the Western Regions.

Now the Western Regions are the territory of the Turks, and the Turks are invading heavily. The Shuofang area was originally a barrier to Xiaoguan, but Shuofang is now controlled by the Liang army.

Longyou Hexi was in the hands of the Tang Dynasty, but Tuyuhun was attacking Longxi again.

The defensive chains in Guanzhong, Longyou and Hexi of the Tang Dynasty are collapsing.

Li Yuan knew very well, and Li Shimin knew very well, so Li Shimin asked for an order to send troops, and Li Yuan would draw 10,000 out of his only 20,000 soldiers to Li Shimin.

Li Shimin's march route was actually to move west along the Weishui River Valley.

This route is not easy to walk, and it is much more difficult than walking on the Jinghe Valley. But the route to Longyou is the shortest.

When Wei and Shu competed for the battle, Zhuge Liang went out of Qishan six times and had been confronting each other in the Longguan area. Now Zhang Chao and the others are re-taking the route of the Wei army Sima Yi.

It is a thousand miles away from Chang'an to Longxi, Weizhou, and even if you reach Longguan, it is more than 500 miles away.

Zhang Chao rode on the horse, took his right rear army to carry food, grass and weapons, and escorted nearly 10,000 civilians to transport food, grass and grass, and the team was long.

But the road is difficult to walk, especially in early summer, with a lot of rain. When the road is soaked in rain, it will be muddy, just like a swamp. The wheels are often stuck in the mud and cannot get up, and even mules and horses cannot pull them, so you have to help lift them.

In order to get off, Zhang Chao had to treat his right rear army as a team of engineers.

Every day, a group of people is transferred to lead the way and a group of civilians is really a way to open up the mountains and build bridges when they encounter water.

From time to time, you can encounter hillsides that block the road for mudslides. You have to dig a road. When the river water surges, you have to block the road. You have to cut down trees and build bridges. For those muddy and difficult roads, you have to cut down trees and pave the road.

The most terrible thing is the rain.

When we left Chang'an, the rain continued to fall. From time to time, there were heavy rains and hail. Even if the heavy rain stopped, the drizzle would continue, and in short, it never cleared.

All food and military equipment are afraid of being soaked in rain and water, so they have to be wrapped and protected.

In this kind of weather, it is wet every day. The most terrible thing is that you can't find dry firewood to make a fire. Basically, you eat dry food every day. Fortunately, the soldiers of the Right Back Army brought some fried rice when they came out, so they saved some food and could still hold on.

Every night, after camping, I find a way to make a fire to make a meal.

"Qi Zhui, there is an open area in front and it is getting dark. Will you camp in front tonight?" A scout leader came over and asked Zhang Chao.

Because Zhang Chao left a good impression on Li Shimin that day, Li Shimin finally made an exception and pulled a hundred cavalry to Zhang Chao, which was the greatest support.

Zhang Chao is also very valuable for these hundred riders.

He organized the hundred men into ten teams, each with ten teams, and asked them to take turns to explore the way forward as scout cavalry of the Right Back Army.

Although he was still marching in the Tang territory, what Zhang Chao was most worried about was an ambush of enemy cavalry.

Although his team is large, with more than 8,000 people, he is either a civil servant or a workshop apprentice. If he accidentally steps into a trap, he will be a waste.

Be careful to make the ten thousand-year-old ship, Zhang Chao is quite cautious.

Every day, scouts and cavalry must be sent out for twenty or thirty miles, and their own infantry reconnaissance teams must be sent to reconnaissance all the way around.

At night, you will never rush to travel.

It was still some time before dark, so Zhang Chao had to find a scout who had chosen suitable terrain to camp overnight.

"Let everyone get off the road and get to the campsite as soon as possible!"

Sitting on the horse in a raincoat is not a very comfortable thing. Although there is a raincoat, the body is actually extremely wet. The war horses are soaked in the rain.

After trekking in the rain for a day, everyone was extremely tired and just wanted to rest immediately, boil a pot of boiling water and cook a hot rice.

The campgrounds for the cavalry scouts candidates were very good, and those people were worthy of being experienced veterans.

In front of that place is a river and behind it is a mountain, like a protruding small plain delta. Camping there, the river is now full, as long as you guard both ends, it can be said that it is very safe.

However, Zhang Chao was not careless. The good terrain did not mean that he could relax.

As Longxi approaches, Zhang Chao is becoming more and more strict in his requirements.

"Carry a chain of camps! Get moving quickly!"

The serial camp that Zhang Chao mentioned was a camp he created himself. The biggest feature of this camp is that it is divided into many camps.

Five thousand civil servants, each with a battalion, surrounded by baggage chariots, then unloaded all the food and supplies and placed them in the center of the chariot array, and covered them with tents. The tents of the civil servants surround the periphery of supplies.

All five civil servant camps maintained a distance of dozens of steps wide.

Zhang Chao's three thousand right rear army was built into three battalions based on battalions, distributed on three corners of the five civil servant camps.

"Outside the car array, dig a ditch, dig some traps, and cut down trees to resist horses!"

Although he was tired and hungry after walking for a day, Zhang Chao would not be able to slacken off. He would ask the civilians to set up camps, and dig a ditch outside the civilians' chariots and soldiers' gun cabinets and horses. If it was early, he would cut down some trees to resist horses and dig some traps to trap horses.

Although I was busy for a long time, I stayed again after a night.

But Zhang Chao insisted every time.

Some of the villagers were camping, some were logging wood, and some led mules and horses to drink water and feed them drinks.

At the request of Zhang Chao, the soldiers of the Right Back Army were still on guard and defending the surroundings.

Daniu, Erniu, Ke Xiaoba and Ke Shisan and fourteen were helping Zhang Chao set up a tent. Zhang Chao's tent was bigger and used better materials. He was not afraid of wind and rain, but heavier, so he had to be pulled by two mules.

A tent was being set up, and the soldiers' tents were relatively regular, which were tents of ten people per person. But many civilians did not have such good equipment. They were summoned to transport grain, and there were no tents at all. They were all brought by their own homes, and many were quite simple. Some civilians even had no tents at all. At night, if there was no rain, they would lie anywhere. If it was raining, they could only find a way to get through. Some sat with a felt cloth for a night, and some built a simple shed with branches.

Later, Zhang Chao established a rule that every time he camped, the villagers helped each other cut trees and wood, and first pressed ten people to build the shed.

In early summer, spending overnight in the wild is prone to illness, but if you catch a cold in the rain, it will be even more troublesome. If you get sick, you will be injured and you cannot transport supplies. Zhang Chao has to find a way to take care of them and let someone hold them to him, which will be even more troublesome.

Zhang Chao's personal soldiers loudly promoted the prosecutors everywhere in the camp.

"Drink raw water by water, boil water before drinking it!"

No drinking raw water is allowed. Every time you set up camp, you should fetch water and boil water first. Every fifty people must dig a toilet first, etc., which are many rules.

But this is the case in the army. There are no rules. How can I lead more than 10,000 people well?

The same is true for grain. After camping every day, the grain is distributed one after another. The army sends it to the battalion, the battalion and the gang, and the gang sends it to the team. The team sends it to the team, and each group eats it together and takes turns to cook.

Although they were still wet, they were well-built, so they quickly took back the branches left over from the horses they made just now to cook. There were dry firewood matches in the convoy, which were well protected, including some pine needles and some hay.

Distribute it with the food every day.

On such a rainy day, without this dry ignition, it would be impossible to start a fire and cook.

Erniu skillfully beat the flint and ignited the dry pine needle.

After a few breaths, the flames became more abundant. Erniu carefully placed the fire in the dug marching stove kang. The kang was dug on the ground, but two oblique holes were dug out on both sides, opening the stove from the bottom to the middle. In this way, the pot was placed on top, and the firewood below would burn better, not easy to extinguish, and not easy to smoke.

The big cow put the folded wet and fine wood racks on it. Although the wood was wet, it was relatively thin and it was roasted and burned in a while.

Erniu took some larger wet branches and put them next to bake.

"Sanlang, you changed your clothes and I'll set them up here to dry them." Daniu performed his duties as an orderly soldier. Zhang Chao sat on a small stool and said tiredly, "I'll do it myself. You took off your wet clothes and baked them. If you wear them for a long time, you will easily catch a cold and get sick."
To be continued...