Why is Song Jun vulnerable? 200,000 people can't beat thousands of Liao soldiers.

Let me give you a detailed answer. First, admit that the source of the horse was cut off. In Song Dynasty, there were no Hetao area and Saibei area, both of which were horse-producing areas, but cavalry could not. It is conceivable that cavalry without armed combat effectiveness. So Song Jun can't fight, only guarding the city. Secondly, the military system of the Song Dynasty was too bad, because the Tang Dynasty was destroyed by the powerful military power of the buffer region, so the rulers of the Song Dynasty overcorrected and suppressed the military power blindly. There were two kinds of armies in Song Dynasty, one was Xiang Army and the other was Imperial Army. Xiang army basically has no fighting capacity, and the number of imperial troops is not concentrated in Kaifeng area, so the final result is that the overall fighting capacity of Song Jun is poor.