The Huns often went south to plunder the Central Plains in winter, and they themselves called this behavior "beating grass valley", which can be understood just by looking at the words.

First of all, the autumn high horse fat, the horse fat is strong and the best state after raising it for more than half a year. In winter, when you eat hay, you have to lose weight.

The second is that the nomads have harvested their pasture in the autumn and are stationed in winter camps, not in the heavy workload of strong labor. A large number of able-bodied men are idle.

Then, the northern peoples and horses were accustomed to dry and cool weather, and the Central Plains in autumn and winter was just right for them.

Finally, the Central Plains region is just the harvest season, and farmers have to invest a lot of labor in harvesting and other labor. The product is the most abundant, and there are the most things that can be grabbed.

In general, nomads go south in autumn and winter, and they can effectively use their horsepower, manpower and weather advantages, and they can grab things that are very profitable. If they don't come out, the good condition of the horses and the abundance of labor will be wasted in the winter camp.

"Fighting the Grass Valley" is different from the big battle between the two armies and the scout war of small troops, which is essentially a kind of economic plunder warfare, the target is the enemy's population, livestock, and wealth, and pursues the basic tactical principle of "taking away everything that can be taken away, and burning all that cannot be taken away". The main feature of this model is that it is not aimed at fighting, but at plundering. This kind of invasion of the Xiongnu was not aimed at conquering cities or fighting a decisive battle with the Central Plains, but had a strong economic plundering color. The Xiongnu are located in the bitter cold land of the north, with little production, harsh environment, and insufficient labor, so they need to obtain a large number of goods from the Central Plains. In peacetime, the two sides barter and take what they need. When the situation was tense, normal trade was interrupted, and the Xiongnu still had a demand for goods from the Central Plains, so it was natural to launch an economic war for the purpose of plundering. The most common descriptions of this kind of "grass valley" in historical books are "slightly more than 2,000 people", "slightly more than 1,000 people", and "killing a lot of people and livestock", which shows how deep the suffering of the people in the northern Central Plains is.

Mao Dunshan, the leader of the Xiongnu tribal alliance, was overjoyed to hear that the state of Zhao was weakened and his troops were exhausted under the continuous attacks of the Qin army.

"In previous years, due to Li Mu's exploits and tricks, our Great Huns couldn't go south to herd horses, it's really hateful! Fortunately, the great Kunlun God did not forget his descendants, and finally the Central Plains people killed each other and gave us a great opportunity. After speaking, the leader of the Xiongnu, Manshan Yu, opened his arms and thanked the Kunlun God for his greatness.

The leader of the Huns, Mandan, was like a madman, and shouted: "Kunlun God! In the name of the god of Kunlun, I swear here! The leader of the Huns, Mandanyu, looked at the noble ministers beside him and shouted: "I will lead you to fly like falcons over the mountains!" Across the lake! Catch for you, blue-footed gray-winged crane! ”

The noble ministers hurriedly bowed their heads in obedience.

The leader of the Huns, Mandanyu, looked at the Hun cavalry not far away and shouted: "Lead you, like wolves, through the green grassland, to loot the villages and towns full of grain, silk, and beautiful women!" “

The Hun cavalry all raised their sabers in respect.

The leader of the Huns, Mandanyu, opened his arms again, looked at the Hun civilians in the distance, and solemnly promised: "Let the men of the Central Plains be our slaves!" Let their women be our concubines! Let their fields become our pastures! Blood-stained dusk, meat fed to the fierce dogs! My brave Hun is the only master of the high heavens, except for the Kunlun God! ”

The Hun civilians all cheered and expressed their support.

They are just for a good life in the future! But who can guarantee that this is not a whimsy?

Kunlun is the source of all ethnic groups in the East and the backbone of the world. The Xiongnu, like most nomadic peoples, revered nature and practiced shamanism. The Kunlun Mountain God is the closest to the heavens, and is naturally the biggest god in the world. Of course, the Xiongnu also believed in the gods of the sun and the moon, that is, the gods of the sun and the moon. The leaders of the northern nomadic tribes have the habit of "worshipping the rising sun in the morning and the rising moon in the evening".

When the Xiongnu invaded Zhao in the south, they had to first conquer the Great Wall in the north of Zhao, referred to as the Great Wall in the north of Zhao.

There are two main Great Walls of Zhao State, the first is the Great Wall in the south of Zhao State, that is, the Handan Great Wall; the second is the Great Wall of Northern Zhao;

The Southern Great Wall of Zhao is the southern Great Wall built by Zhao along the coast of Zhang and Fu in Handan, mainly to defend against the invasion of Wei in the south. Generally speaking, this Great Wall starts from the southwest of present-day Wu'an, goes southeast along Zhangshui, to the southwest of present-day Cicheng, turns northeast, and reaches Feicheng along Zhangshui. In addition, in order to resist the strong Qin in the west, the Great Wall of Qin and Zhao was built, which started from Huixian County, connected to Hanoi (now Qinyang County, Henan) in the south, and reached Fuyang (now Fuyang River, Wu'an County, Hebei) in the north. However, the effect does not seem to be good, because the Qin State has already come in.

The Great Wall in the north of Zhao was built in 306 BC. At that time, King Wuling of Zhao defeated Lin Hu and Lou Fu, and developed Yanmen, Daicheng, Yunzhong, Jiuyuan, these places, began to build the Great Wall, starting from Daicheng in the east (in the territory of Zhangjiakou, Hebei today), through Yunzhong, Jiuyuan (in the territory of Baotou City, Inner Mongolia today), turning into Yinshan in the northwest, and reaching Gaoque (the gap between Wula Mountain and Wolf Mountain in Inner Mongolia today), which is about 1,300 miles long. The ruins of this section of the Great Wall of Zhao still intermittently lie between Daqing Mountain, Wula Mountain, and Wolf Mountain. Later, when Qin Shi Huang built the Great Wall, he used this section of the Great Wall of Zhao as a foundation.

The construction of the Great Wall originated from a large number of water conservancy embankment projects. From the Spring and Autumn Period to the Warring States Period, large-scale embankments were built on major rivers as the peasants gained rich experience in the production struggle and improved the technology of building embankments. At that time, the ruling class was waging wars, and due to the expansion of the scale of the war and the movement of the mode of war, it was very necessary to build large-scale defense projects, so they used the technology of building embankments to expand the original large river embankments on the border, and transformed the original water conservancy projects into military defense projects. Of the Seven Warring States, the Qin state in the west began to build fortifications along the Yellow River as early as 461 BC in order to prevent Wei attacks. The six countries of the Kwantung region also built the Great Wall in their own dangerous places.

The leader of the Huns, Mandanyu, led 200,000 Hun cavalry to the south, and hundreds of thousands of cattle and sheep accompanied the army, all over the mountains. The Huns' troops pointed directly at the Yanmen Pass guarded by Li Mu. Yanmen City is not only a Xiongguan, but also a military center in the north of Zhao State. Yanmen Pass is located between the east and west mountains of Yanmen Mountain, the east and west mountains confront each other, its shape is like a door, and the flying geese come out of it, so it is called Yanmen Pass.

Yanmen City Guard.

Li Mu, the general of Zhao State, heard that the Xiongnu were moving south, and knew that the Xiongnu wanted to take advantage of the weakness.

Li Mu stroked the white beard under his forehead and closed his eyes in contemplation. For a while, the old general's majestic body was still so tall and tall, and his white beard was also flying briskly, he was really a god of war!

"General, the Huns are not good. Handan has transferred most of our troops, and now it is not enough to defend the city, how can we repel the Huns. Deputy General Sima Shang asked worriedly.

"Since you can't defend, then take the initiative to attack!" Li Mu, the general of Zhao State, suddenly opened his eyes and said loudly.

"Take the initiative? How to attack? The deputy general Sima Shang is a brave general, but unfortunately his resourcefulness is insufficient, so he asked suspiciously.

"The most poisonous plan is to cut off water and food, and the most ruthless is to attack fire with water!" Li Mu thought for a moment and said in a deep voice, "This time, the Huns raised 200,000 troops to the south, but the logistics of the Huns basically relied on hundreds of thousands of cattle and sheep that came with the army. One thing, everyone understands, the hundreds of thousands of cattle and sheep of the Huns will never be able to gather together, because it takes thousands of miles of grasslands to barely feed these cattle and sheep. Then this creates a unique opportunity for us. ”

"200,000 Huns, marching and fighting for three months, brought at least 500,000 cattle and sheep. 500,000 cattle and sheep are distributed across the grasslands for thousands of miles, and the grass is scarce under the snow in winter, so they must be divided into at least 100 pastures. The Huns had at least 100,000 people under the Yanmen Pass, so the remaining troops of each ranch would not be more than 1,000. Adjutant General Sima Shang calculated slowly, and the more he thought about it, the happier he became.

"Yes, the old man quietly selected 10,000 iron horsemen, divided into five teams, and ran to the pastures of the Huns from a distance. If it succeeds, the Huns have no cattle and sheep, how can they stay in Yanmen for a long time! Zhao Guo's general Li Mu was also overjoyed.

Needless to say, the cavalry of Zhao State knows that King Wuling's Hufu cavalry and archery reform is actually replacing the carriage soldiers with a light cavalry that imitates the equipment of the Hun cavalry! That is, Hufu Flying Ride! The equipment of the Hufu Flying Horse should be a long spear, a long sword, a short bow, and two quivers! They move very fast and come and go like the wind.

Li Mu made full use of this, so in the northern frontier, the cavalry of the Zhao State often suddenly appeared in front of the Huns, and then beat them hard! The so-called "soldiers are fast and fast", and the army runs fast, that is the royal road.

In order to make the Zhao army faster, Li Mu also carried out the military food reform! When he was in the northern Xinjiang, he found that the drinking of the common people in the steppe was called mare's milk wine. This thing is not only drinking, but also very hungry when you are full. So Li Mu introduced it into the army! Li Mu asked Feiqi to bring a bag of mare's milk wine and two flour cakes every time, so that the cavalry of Zhao State could eat for three days, but it was much lighter than the weight of other grains in one day! So Zhao Jun's speed was faster, coming and going, and he could walk hundreds of miles a day. After the cavalry of Zhao caught the Huns and beat them, they ran home, filled them with mare's milk wine, and came out again to fight. This trick made the Huns miserable, and they almost didn't call Li Mu to be their godfather. These Zhao cavalry are called "Zhao State Flying Cavalry"!

And Li Mu is also known as the first "flying general" in Chinese history! His descendant Li Guang has the reputation of "but making Longcheng fly and not teaching Humadu Yinshan".