Mythical Qin: I, Gao Yao, will never be a eunuch!

Moreover, more importantly, the location of Heilongkou is right on the throat of the road in and out of Nanhai County, which is the only way for pedestrians and troops to pass. However, surprisingly, it is very far away from the surrounding county towns and other densely populated areas, but close to the wide road. In this way, whether it is a long-distance raid or a fast march, it can be greatly facilitated here.

For the imperial army, Heilongkou is undoubtedly the most ideal place for attack. The entire Heilongkou is nearly 20 kilometers long, with two dangerous gaps at both ends. As long as these two gaps are firmly blocked and gradually pushed inward, the enemy trapped in them will be unable to escape. Because inside Heilongkou, the two sides are either steep cliffs or bottomless swamps and quagmires, and there is no other feasible way to break out. Even the Southern Border Army, facing such a natural barrier, may not be able to escape the fate of destruction. The key is that this is also the place that Gao Yao must pass when he leads his army back to Nanhai County.

This distance was just right for the imperial armies of both sides to ambush on both sides of the road, thus achieving the strategic goal of besieging Gaoyao and making it impossible for the enemy to escape. Everything in the world has two sides, and every advantage has its disadvantages. The topography of Heilongkou is certainly conducive to ambushing and even pursuing the enemy, but there are also some problems that cannot be ignored.

First of all, the area of ​​Heilongkou is quite vast. If marching at a normal speed, its width is wide enough to accommodate thirty or forty horses galloping side by side. In addition, there is an adequate supply of water. In this case, if you try to rely solely on fire attack tactics or launch a surprise attack from the top of the mountain, although it is not completely impossible, the results that can be achieved are probably quite limited.

In fact, the most ideal attack strategy should be to lead the troops to charge directly from the front and back of Heilongkou, forming a pincer attack. Unfortunately, due to the special terrain of Heilongkou, the number of soldiers who can participate in the battle at the same time on the same horizontal plane is only a few hundred. This means that the huge advantage of the imperial army in terms of manpower will be greatly reduced here. Unless this battle lasts for a long time and the opponent's strength is gradually consumed by continuously investing troops, it will be difficult to show a significant difference in the outcome of the battle in the short term.

There are many disadvantages for the Southern Border Army. The most obvious one is that the Black Armor Army is almost useless here. It turns out that there is a lot of soft soil in the passage inside the Black Dragon Mouth, and there are many areas like swamps formed by stagnant water. If it is just an ordinary march, the army can still avoid these areas in time, and even if they encounter some troubles, they can find ways to resolve them.

But in the fierce battle, these seemingly insignificant obstacles are likely to turn into extremely fatal problems. After all, the terrain here is not suitable for cavalry to charge, so the advantage of the Black Armor Army will be gone.

In addition, this geographical location has another unique advantage, which is precisely the key reason why the mysterious figure Yi Xiaochuan finally decided to take action here. That is, this place is extremely unfavorable for the use of gunpowder. The reason is that on the one hand, the surrounding forests are dense and dense, and there is a lot of broken soil and mud; on the other hand, such environmental conditions are relatively unfavorable for the effective use of black gunpowder.

After experiencing the thrilling battle, the mysterious Yi Xiaochuan still remembered the black powder that Gao Yao had mastered. Although he was shocked by the powerful explosion at that time, he quickly discovered some key problems with his keen insight and profound knowledge.

After a meticulous study, the mysterious Yi Xiaochuan realized that the black powder in Gao Yao's hand was still in a relatively early stage of development. This primitive form of black powder not only has unstable performance, but also has extremely strict requirements for the use environment and operation methods. Especially in the complex and changeable geological conditions like Heilongkou, the use of black powder has brought great restrictions and risks.

In this situation, if you rashly use black powder to attack the enemy, it will undoubtedly lead to a tragic situation of "hurting one thousand enemies and hurting eight hundred of your own." It is based on this consideration that the meticulous Yi Xiaochuan made up his mind to launch a fatal attack on Gao Yao at Heilongkou.

In order to ensure that the operation could be carried out smoothly and achieve the expected goals, the mysterious Yi Xiaochuan carefully planned and deployed, and even did not hesitate to let the imperial army take a detour. He knew that once the army was caught in a battle to siege the city, it would inevitably delay precious time, thus giving Gao Yao a chance to catch his breath. Therefore, during the march, whenever they encountered a city, they would try to choose to detour; and if they encountered harassment from the enemy troops defending the city, they would quickly divide a part of their forces to fight with them in order to contain the enemy's strength, while ensuring that the main force continued to advance at full speed in the direction of Gao Yao.

In short, Yi Xiaochuan's core purpose of this action is only one - that is to achieve the primary strategic goal of completely annihilating Gao Yao and his forces. To this end, he mobilized all available resources and devoted himself to this life-and-death contest.

Less than three kilometers away from Heilongkou, Zhang Liang stood quietly in front of the military tent, his deep eyes staring at Heilongkou not far away, and he couldn't help but let out a long breath. At this moment, looking around, there were countless tents, but in fact, most of the military tents were empty, without a single soldier.

This was completely different from the intelligence obtained by the mysterious Yi Xiaochuan, who said that the force was close to 20,000, but in reality it was far less than 5,000. The reason why they stopped and started along the way was to cover up the true number of troops.

During the entire march, the front army always set out first, followed by the middle army, and finally the rear army. Surprisingly, these three armies almost never marched at the same time, but adopted an extremely clever strategy: sending a small force to advance for a distance and then quickly withdrawing. At the same time, the scouts responsible for counting the number of people were dispersed to count independently. In this way, almost the same number of soldiers was counted three times!

Moreover, in order to further confuse the enemy and make them fall into deeper confusion, the soldiers even spent a lot of energy to change the armor they wore twice during the operation. Not only that, they also cleverly created a large number of various and seemingly chaotic other related traces to achieve seamless and close coordination with each other.