For example, the locals knew that to defend the Yangtze River, one must guard the Huaihe River, but Sun Quan didn't know.

In other words, he didn't know it before.

For another example, everyone in the world knows that "he who wins the Central Plains wins the world."

But only those with outstanding vision know that before conquering the Central Plains, it is best to first occupy Guanzhong or Hebei in the west, and the second level must be at least the south.

After you have no worries, you can then compete in the Central Plains, and then you can easily win the world.

But even those with outstanding vision cannot break through the limitations of the times and see things thousands of years from now.

Before Li Tang raised troops from Taiyuan and conquered the world, even if some people paid attention to merging states, probably no one could realize how important the mountains and rivers inside and outside were.

During the Pre-Han Dynasty, after the Xiongnu were first divided into northern and southern parts, the area from Yinshan Mountain to Yanmen has been a place where the Han people kept watchdogs for hundreds of years.

It's just that during the Han Dynasty, the Southern Xiongnu were raised.

By the end of the Han Dynasty and the Cao Wei Dynasty, the gatekeepers became Xianbei people.

Although the guard dogs sometimes want to turn around and bite their masters, they are always knocked down by their masters, who then drive them to bite the enemies in the north.

When Kebineng was at its strongest, Bu Dugen stayed in the Yanmen area, guarding the Wei people in exchange for Wei's support, so that he could avoid being annexed by Kebineng.

As one of the most important barriers in the north in later generations, Yanmen did not set up defenses against the barbarians for two to three hundred years. From this, we can see the strength of the Han Dynasty.

But at the same time, it has also deeply imprisoned the thinking of most people in this era.

Generally speaking, twenty or thirty years is enough to tamper with people's impression of history.

Take for example later generations’ impressions of World War II. In the 1960s and 1970s, the West still recognized that the Soviet Union defeated Germany.

By the 1980s and 1990s, it became the United States and the Soviet Union to defeat the Axis powers.

After the fall of the Soviet Union, some blockbusters began to vigorously promote the United States as the savior of the world.

Ten years after the millennium, some people have begun to claim that the Soviet Union is an accomplice of the Communist Party...

A few decades can distort history to such an extent, not to mention that the practice of using the Yanmen area to raise barbarians as gatekeepers in the Han Dynasty lasted for hundreds of years.

No one in Wei could see more than a thousand years later, so they didn't know how sleepless a Song Dynasty was after losing the Sixteenth State of Youyun.

Even Cao Cao would not have thought that after he dismembered the Huns into five tribes, the Huns would come back a hundred years later.

Therefore, it is not wrong for the Wei State to follow the practice of the Han Dynasty and keep Xianbei Hu people in Yanmen County to visit the gate.

The mistake was that they forgot that they were not a unified Han Dynasty. Their main energy was to fight against the south and the west.

Instead of mobilizing the entire country's troops to the north like the Han Dynasty did.

Therefore, they would not have thought that King Feng Gui sacrificed 20,000 Xianbei barbarians in front of all the Wei troops at Qiaoshan.

Then he acted like he was anxious to return north and fight to the death with Ke Bi Neng. This was actually just to cover up one ultimate goal: Yanmen County.

At this time, the person working as a guard dog for Wei in Yanmen County was Xie Guini.

Bu Dugen, the first Xianbei gatekeeper at Yanmen, had an elder brother named Fu Luohan.

Xie Gui Ni is Fu Luohan's son.

Back then, Fu Luohan and Ke Bineng made an oath, but Ke Bineng was hacked to death in public.

His own master was hacked to death in front of him. Not only did Xie Guini not think about revenge, but he led tens of thousands of cavalry to join Kebineng, the enemy who killed his father.

A few years later, he was persuaded by Bu Dugen who was stationed at Yanmen, so he led his men to secretly join his uncle.

Unexpectedly, Bi Gui, the governor of Bingzhou, was arrogant and extravagant. He often took advantage of the Hu people and made the Hu people in Bingzhou miserable.

Bu Dugen was so angry that he would rather join his entire family to join his mortal enemy Kebineng than be bullied by Bi Gui.

Bi Gui led his troops out of the pass without authorization, and was defeated by Ke Bi Neng at Loufan to the west of Yanmen Fortress, and his entire army was almost annihilated.

Then Qin Lang led the Chinese army north to Bingzhou and defeated the coalition forces of Ke Bineng and Bu Dugen.

After Kebi was defeated, his vitality was severely damaged, so he simply killed Bu Dugen, annexed the remaining members of his tribe, and ran to Yinshan to lick his wounds.

As for Xie Guini, they both defected again, and he and his remaining troops ran back to Yanmen to surrender to Wei.

Cao Rui didn't care about his past, and even named him the King of Guiyi, allowing him to continue to lead his troops to guard Yanmen County.

This person, Xie Gui Ni, can be said to be a veritable domestic slave of the third surname, and judging from his actions, it is not an exaggeration to say that he is as timid as a mouse.

But it was precisely because the people stationed at Yanmen were Xieguini that Governor Feng never thought of breaking through from Qiaoshan from the beginning.

Instead, he made a set of fancy moves to confuse the Wei State, and then sent Guan Suo to raid Yanmen at the critical moment.

Just when Cao Rui was having a sweet dream about two thieves, Feng Yong and Ke Bineng, fighting each other and losing both sides.

Guan Suo has led 20,000 iron cavalry, traveling day and night, rushing eastward.

Then it turned back to the south, and finally rested briefly at the pass built by the former Han Dynasty in the north of Yanmen County.

When the Han Dynasty was strong, a fortress was built on the northern border of Yanmen County.

It's just that now the pass has long been in dilapidated condition like the pass in Juyan County.

The current boundary actually controlled by the Wei State is the Hengshan Mountains in the south of Yanmen County.

To the north of the Hengshan Mountains, there is a basin, which is later known as the Datong Basin. This is the general scope of Yanmen County.

Ever since Qin Lang defeated the coalition forces of Ke Bineng and Du Bugen, the two states in the north have been peaceful for a long time.

August is approaching, which is the best time for grazing on the grassland.

The yurts are dim, the smoke is curling, the sheep are bleating, and the horses are neighing.

Although Xie Gui Ni was allowed to stay in Yanmen County by Wei State, in fact, no one could compete with him.

Over the years, his tribe has occupied large tracts of good pasture.

Inside the fortress you can exchange grain and cloth with the Han people, and outside the fortress there is fertile land for grazing sheep and horses.

There are even occasional caravans coming to exchange some rare and rare things.

Xie Guini's life has been really comfortable these past few years.

He even felt that such days seemed to go on forever.

And far away under the Qianhan Pass, a pair of extremely deep eyes seemed to be staring coldly at this peaceful and peaceful land through the mountains in front of them.

PS:
Chapter completed!