What role did the Yellow River play in causing the Hangu Pass, which could be managed by one man, to be abandoned?

For people who often travel between Shaanxi and Henan, there is a place name when passing through Sanmenxia: Hangu Pass. However, today's Hangu Pass has long been abandoned and has become a tourist attraction. There are railways and highways passing nearby. Perhaps when driving or taking a train, Hangu Pass was just a place name passing by on the road. However, more than two thousand years ago, This is the only way to enter Guanzhong from Luoyang to the west. Since Hangu Pass guards the throat of Xiaohan, it is connected to Hengling Mountains in the west, Juejian Mountain in the east, Qinling Mountains in the south, and the Yellow River in the north. The terrain is dangerous and the roads are narrow. It is said that "a chariot does not have a square track, and a horse does not have a bridle". It can be said that one man can't stop ten thousand people from driving.

The terrain here is steep. To the west is the red dusty Loess Plateau, to the east is a thousands-foot-high ravine, to the south is the dangerous Qinling Mountains, and to the north is the majestic Yellow River. There used to be a Hangu Road here that was about fifteen kilometers long. This Hangu Road was just a crack in the Chomulus Plain. The height of this Chomulberry Plain was very high. It was surrounded by steep cliffs and was covered with big trees. It was impossible for ancient infantry to climb over the mountain. To the north of Choosangyuan is the Yellow River. The river flows close to the original wall. This is the miraculous workmanship of nature. It has left such a gap for people to cross. I believe many people have crossed the line of sky. , here, this is probably the feeling.

I have to mention the Yellow River. The Yellow River gushes down from the upper reaches, passes through the border of Shanxi and Shaanxi, and then to Henan. At the location of Sanmenxia, ??year-round erosion has formed a very steep terrain. In which era, the construction of It is extremely difficult to build a bridge on the road. People can only follow the terrain when crossing, and eventually they all converge on this Hangu Road, traveling from east to west through Hangu Pass. With the establishment of the Zhou Dynasty, King Zhou Wu at that time established his capital in Haojing. In order to better control the Guandong region, King Zhou Cheng decided to establish Luoyi in Luoyang, located in the land of Heluo, as the seat of the royal family. Soon King Ping moved eastward, and a new vassal state gradually emerged in the original Guanzhong Plain: Qin.

The ancestors of the Qin State were herding horses for the Emperor of Zhou. Because they raised horses well, they were made a vassal state by the Emperor of Zhou, King Xiao. When King You of Zhou fell, the then Duke Xianggang of Qin sent troops to escort King Ping of Zhou to move eastward, and was once again named a vassal state. The land west of Qishan Mountain was given to the State of Qin. From then on, the State of Qin officially became a member of the vassal state. .

In the era of Duke Mu of Qin, the State of Qin began to expand externally, gradually reaching the eastern part of the Guanzhong Plain, and basically occupied the entire Guanzhong. At that time, the State of Jin once sent troops to garrison Hangu Road to prevent Qin from moving eastward. During the era of Duke Xiao of Qin, after several battles with the Wei State at that time (after the three families were divided into the Jin Dynasty), the Qin State finally won the land of Weihan and immediately established Hangu Pass.

During the Spring and Autumn Period and the Warring States Period, the Qin State sitting on Hangu Pass could be said to have an advantageous location, making it easy to defend and difficult to attack. There had been many six-nation coalition forces attacking Hangu Pass, but most of them returned without success. . In the sixth year of Gengyuan of King Qin Huiwen (319 BC, that is, the sixth year that Ying Si became king), King Wei expelled Zhang Yi and changed Gongsun Yan to the position of prime minister, implementing the policy of unification. The following year, the five kingdoms of Zhao, Wei, Han, Yan, and Chu elected King Huai of Chu as their commander and jointly attacked Qin. However, the five kingdoms were in vain and had their own evil intentions. After the Qin army defeated Zhao, Wei and Han outside Hangu Pass, the alliance collapsed. In the 30th year of King Anli (247 BC), Lord Xinling sent envoys to inform the princes. Zhao, Han, Yan, Chu and other countries sent troops to rescue Wei one after another, allowing it to control the situation. The prince then led the troops of the five countries to defeat the Qin army outside Hebei (today's south of the Yellow River in western Henan). Qin general Meng Ao was defeated and fled. Although he took advantage of the victory and drove the Qin army to the outside of Hangu Pass, he was unable to break through the pass and enter. The advantages and dangers of Hangu Pass can be seen clearly.

However, Hangu Pass was also breached. This happened in 298 BC. Mengchangjun of Qi State joined forces with South Korea and Wei to attack Qin State, all the way to Hangu Pass. After that, they continued to attack for three years. In 296 BC, they finally broke through Hangu Pass. Xianyang, the capital of Qin, was shaken. Qin was forced to sue for peace and returned Wei's Hewai and Fengling that it had captured before, as well as Hanwai and South Korea's Hewai. Wu Sui then withdrew his troops. Then until the fall of Qin, Hangu Pass was never breached again. When Liu Bang entered Guanzhong, he took Wuguan Pass, then crossed the Qinling Mountains and arrived at Guanzhong. When Xiang Yu knew that Liu Bang had arrived in Xianyang first, Xiang Yu was furious and directly led his army to attack Hangu Pass. In the end, Liu Bang and Xiang Yu reconciled at the Hongmen Banquet, and the Qin Empire was destroyed.

During the period of Emperor Wu of the Han Dynasty, Emperor Wu of the Han Dynasty ordered the Hangu Pass to be moved 300 miles eastward from Sanmenxia Lingbao to Xin'an County, Luoyang. The original Qinhangu Pass became Hongnong County. It is said that it was because Yang Pu was the Louchuan general and successively pacified the South Vietnam Kingdom and the East Vietnam Kingdom, and made great military achievements. However, Emperor Wu of the Han Dynasty distributed the land in Guanzhong to meritorious officials of the dynasty, except Yang Pu. Emperor Wu of the Han Dynasty told him that after the land within the pass is divided, you can become a marquis outside the pass. Yang Pu was unwilling to be a Marquis outside Guan, so he wrote to Emperor Wu of the Han Dynasty, requesting that Hangu Guandong be moved to his hometown of Xin'an County. In order to expand the territory in Guanzhong and strengthen control over Guandong, Emperor Wu of the Han Dynasty agreed to his request. In the third year of Yuanding (114 BC), Louchuan General Yang Pu led his subordinates and disciples to move Hangu Pass eastward to Xin'an County, 300 miles away. In "General History" written by Ying Shao of the Eastern Han Dynasty, he told the story of Yang Pu who was "ashamed of being a foreigner". Ban Gu's "Book of Han" records that "it moved to Han Valley and was about Xin'an, and Guguan was called Hongnong County."

However, regarding this point, it is generally believed that Emperor Wu of the Han Dynasty wanted to expand the scope of Guanzhong, but it was also related to the geographical environment at that time.

In the Han Dynasty, the Yellow River flowed close to the plateau, and the only way to pass through it was to climb the plateau. However, as the Yellow River continued to wash away, the river channel continued to deepen, and the river bed continued to decline, the original river bed would be exposed, forming a river beach, resulting in the loss of natural dangers. , when pedestrians come out of Huangxiang Slope, they don’t have to go to the plateau, they can just pass by the river beach. In this way, Qinhangu Pass lost the excellent advantage of one man being able to pass the pass and no one could open it. It was slowly abandoned and was eventually replaced by Tongguan.

It is really the continuous erosion of the Yellow River that created the unique topography of Hangu Pass. In the end, it was the Yellow River that made Hangu Pass lose its advantage. The uncanny workmanship of nature is really amazing!