In fact, Shanhaiguan is not just an isolated gate, but an overall fortification formed by several cities with Shanhaiguan as the center, which are interdependent and constitute a perfect defense system.

Therefore, for the defenders, it is necessary to divide troops to garrison in various important places, it seems that the defenders of Shanhaiguan have 20,000 officers and soldiers, but to defend such a large area, it has also diluted a lot of troops, so the overall strength is a little weak, but for the attacking side, it is not easy to defeat Shanhaiguan, because they are facing a complete defense system, and it is impossible to break through the entire defense system of Shanhaiguan only by breaking a little.

Shanhaiguan is north of Jiaoshan Mountain, south of the Bohai Sea, the easternmost is the old dragon's head, the Great Wall extends to the sea, and Shanhaiguan is the city of high walls, outside Shanhaiguan also built Dongluo City, Xiluo City and the north wing of the city, the south wing of the city and other satellite cities sanitation in the vicinity of Shanhaiguan City, each other is the horn of each other, can support each other in wartime, it can be said that it is easy to defend and difficult to attack, here is also the Jiannu army this time into the Kou, the place must be taken, so the main forces of the three parties, they are concentrated inside and outside Shanhaiguan, the whole gathered more than 100,000 soldiers and horses, It can be said that this belt is blocked.

After Wu Xiang and Feng Weihan reached an agreement, Wu Xiang ordered to "resist" the attack of the Great Chinese Army on the Shanhaiguan area, saying that it was resistance, but in fact, to put it bluntly, it was a change of defense.

Funingwei to Shanhaiguan is only about 100 miles, if you ride a fast horse, you don't need half a day, you can rush to Shanhaiguan, so Yan Chongxi in order to guard against the long night dream, he first sent Wang Chengping to lead the left army of 7,000 cavalry to Shanhaiguan, as for other infantry and heavy artillery and other troops, they then arrived.

When Wu Xiang swayed from side to side before, in order to prevent the Dazhong Army from attacking Shanhaiguan from behind, he also transferred nearly 6,000 officers and soldiers from the limited forces at hand to place them on the Shihe line south of Shanhaiguan, trying to prevent the Dazhong Army from attacking Shanhaiguan, so the strength he had on hand to resist the Jiannu army was even more stretched, but now Wu Xiang has made up his mind to take refuge in the Dazhong Army, and these officers and troops along the Shihe River received orders before dawn and withdrew to the Great Wall. And was stationed in the enemy towers along the Great Wall of Shanhaiguan, which immediately greatly enhanced the defense force on the front line of the Great Wall.

As soon as the light of day brightened, Dolgon on the Jiannu side had also realized that it was unrealistic to persuade Wu Xiang to surrender to their Jiannu side, considering that there was a large Chinese army on the other side coveting Shanhaiguan, he was afraid that the large Chinese army would enter Shanhaiguan in front of him, and join Wu Xiang's Ming army to enhance the defense strength of Shanhaiguan, so he ordered his troops to get up and bury the pot to make rice, the fourth watch to make rice, and the fifth watch set off, and a large number of men and horses were dispatched at dawn, and began to launch an extremely fierce attack along the Shanhaiguan, Trying to seize Shanhaiguan first, even if it was the worst, he had to open a few gaps first, so that his superior forces could enter the pass first and launch an attack on the Dazhong army and the Ming army under Wu Xiang from inside the Great Wall.

In this regard, Dolgon still has a certain degree of certainty, after all, after all these years of operation, many Ming soldiers in the defenders around Shanhaiguan have expressed their willingness to surrender to their Jiannu side, so even if he can't beat Shanhaiguan, at least he can open a few gaps in the Great Wall.

But Dolgon didn't know that just one night had passed, and the situation in Shanhaiguan had changed dramatically, and with the help of the intelligence system of the Great Chinese Army, Wu Xiang had made up his mind to defect to the Great Chinese Army on the same night, and carried out an unprecedented purge among the defenders of Shanhaiguan.

After all, Wu Xiang is a veteran of Guanning, and there are still some means to control the generals, and his character is not lacking in decisiveness, but he was not able to make up his mind, but once he made up his mind, he was ruthless, and that night he arrested dozens of officers at all levels who secretly contacted Jiannu to try to surrender to Jiannu, and executed them all in the middle of the night, and hung their heads on the city, in order to deter the army, although individual generals found that the momentum was not right, and tried to resist, However, they were already surrounded by the large Chinese army side of the fine work and the early purchase of the inner line, these people did not wait for them to raise troops to rebel, then the killer was painful, when Wu Xiang sent people to arrest people, they quickly cooperated with Wu Xiang to control the soldiers and horses of these anti-generals, and soon changed the main general, and re-stabilized some not very peaceful troops.

When Dolgon's troops stormed the Great Wall along the Shanhaiguan Pass, they suddenly found that the resistance of the Ming army along the Shanhaiguan Pass was very fierce, all kinds of artillery fire rose one after another, and the attacking Jiannu army suffered heavy casualties, and there was no obvious sign of resistance to release water.

Although the Guanning army has declined in this era, after all, it is a group of people and horses that have been raised by the Ming Dynasty for decades, gathering the power of the world, and now although it is withering, the quality of the equipment of these generals guarding the Shanhaiguan area is still countable in the world.

More Shangshan Customs is the north gate of the Ming Jingshi, and it is the last line of defense against Jiannu, no matter which Jiliao Governor takes office, he does not dare to take the defense of Shanhaiguan lightly.

Earlier, there was no enemy tower on the Great Wall, but after Qi Jiguang went north to the defense of the Guanning area, he began to build an enemy tower every three miles on the Great Wall, in addition to being able to provide shelter for the defenders, it can also enhance the defense force of the Great Wall, so the Great Wall in the Shanhaiguan area is not only strong, but also has a very perfect defense function, and if you want to conquer the Great Wall here, it is not possible to shed enough blood.

Nowadays, most of the Guanning army has long ceased to exist, or was destroyed by Jiannu, or was transferred into the Guannei by the imperial court and destroyed in various battlefields, the more than 20,000 Guanning troops under the command of Wu Xiang can be said to be the only remaining fruit among the entire Guanliao armies, but the quality of the weapons in the hands of these Shanhaiguan defenders can also be said to be the best among the armies.

It is precisely because of the importance of Shanhaiguan that the Ming Dynasty has attached great importance to the defense here, and the best weapons are often issued to the Shanhaiguan area first, so on the Great Wall on the first line of Shanhaiguan, the artillery density is probably the most dense area in the world in this era.

These artillery styles are complicated, there are old guys who are more than 100 years old, and there are also newly cast Hongyi cannons in recent years, among these cannons, there are both old-fashioned copper and iron Dafa guns weighing 500 kilograms, as well as slightly new-style various types of Fulong machine guns, and there are many old-fashioned bowl-mouth guns, exterminating guns, and many tiger squat cannons created by Qi Jiguang, in short, there are all kinds of firearms, and there are many such firearms densely scattered all over the place along this section of the Great Wall that is not too long.

As for these Shanhaiguan defenders, there are also a large number of gunners who operate artillery, although the degree of training of the officers and soldiers is limited, but in comparison, these Shanhaiguan defenders still have to practice every three or five times, so there is not much problem in using these messy artillery.

And these Shanhaiguan defenders have a large number of other firearms on hand, the most popular is probably even the three-eyed gun, the three-eyed gun was popularized in the Ming Dynasty, it was popularized from the Guanning army, in order to strengthen the combat effectiveness of the Guanning army, from the Wanli period, to the Apocalypse year, and in the Chongzhen period of the past ten years, the Ming Dynasty created a large number of three-eyed guns for the Ming army, equipped to the armies, and the Guanning armies are obviously far more equipped than the Ming army in other places, followed by the bird guns, after the Korean War, The Ming army found that the iron cannon used in the hands of the little devil was sharp, and on the Korean battlefield, it caused a lot of damage to the Ming army, and the strength of the Ming army was in the artillery, and finally won the Korean War, but at the same time, it was also found that the individual firearms of the Ming army were weaker than the little devils, so after the Korean War, the Ming Dynasty began to imitate a large number of iron cannons of the little devils, and improved them, and produced the Ming Dynasty's bird's beak gun, that is, the bird gun, and began to be equipped in large quantities in the army, and the most equipped is naturally the Guanning army.

Therefore, the Ming army in Shanhaiguan has a high proportion of firecrackers, and it can even be said that it exceeds the proportion of firecrackers in the large Chinese army, and the firepower is quite strong.

Originally, this Ming army of soldiers and horses, guarding Shanhaiguan, should play an important role in the history of Jiannu's invasion of the Central Plains, but as we all know, due to a series of mistakes made by Li Zicheng in the original history, Wu Sangui finally surrendered to Jiannu, these Guanning troops under the command of Wu Sangui, turned around and became the vanguard of Jiannu to seize the Central Plains in the south, and the Shanhaiguan defense line, which should have played an important role, did not play any role at all, but Wu Sangui blocked Li Zicheng's Dashun army in Shanhaiguan, and united the Jiannu army, Li Zicheng's Dashun army fell into a slump, defeated again and again, and even Li Zicheng finally died in Huguang Mountain in a daze, allowing Jiannu to drill a big loophole before entering the Central Plains.

However, the current situation is different from the original history, Wu Xiang was finally forced to take refuge in the side of the Dazhong Army, and led these Guanning troops to defend the Shanhai Pass, although Dolgon brought seventy or eighty thousand Jiannu troops, and launched a fierce attack on the Shanhaiguan line, but this move, Dolgon only learned the power of the Shanhaiguan Pass and the Great Wall in this area.

After Feng Weihan cooperated with Wu Xiang to clean up a group of generals who tried to surrender to Jiannu, the Ming army was tantamount to unifying their thinking, although the army also caused some trouble because of the change of generals, but this impact was limited, compared to letting those generals defect, the harm that might be caused, can be said to be insignificant.