Why did Fa Zheng want Zhang Fei to withdraw from the army? It's really not for merit - Fa Xiaozhi is not so careful, plus he is a strategist sitting in the rear, so what is the merit to compete with the generals who are charging ahead? If you really want to talk about merit, has Fan Hao won Zhang Liang? Even if you are Liu Bang's new boss, so what?

Fa Zheng's intention was to relieve the crisis in Chen Cang, so that Zhang He could wave his army north at any time and attack the coalition forces under the city of Zhengdun Bingyong County - of course, if there was no main force of Xiahou Yuan to respond, it is estimated that Zhang He would not dare to come, at most it would be just an illusion of being a northern finger. But in this way, if Xiahou Yuan wants to copy the back road of the coalition army, he will inevitably go through the northern road, and will not go between Yongxian and Chencang - even if he is stationed in the northern plains of Weishui, he will inevitably go around such a big circle.

Because only by going around in circles can the optimal strategic situation be formed, that is, to form a new triangle with Yongxian and Chencang in Gukou - Xiahou Yuan is not stupid, and it is estimated that the whole set of strategies, in the face of various forms of coping strategies, has already formed an established plan.

In this way, it can be roughly judged that Xiahou Yuan's purpose is to pass north from Yongxian County, pointing directly to the exit of the Huangshui River Valley, in a vain attempt to restore its original third line of defense. As long as you set up men and horses in advance, and find a way to limit the range of movement of the cavalry and slow down their speed, you will have a chance to gather and annihilate them!

If it is between mountains and hills, then this preset battlefield is easy to find, even if it is a plain, even if it is densely forested, it is also convenient