Why did the ancients attack Guanzhong from Hanguguan or Tongguan instead of crossing the Yellow River from Shanxi?

The ancients attacked Guanzhong mainly through Hanguguan or Tongguan instead of crossing the Yellow River, mainly for geographical reasons. Passing Hangu Pass is the plain, so laying Hangu Pass or Tongguan Pass is equivalent to quickly occupying Guanzhong. For the military conditions at that time, crossing the Yellow River was not the best choice. On the one hand, it is easy to be annihilated. On the other hand, most of the ancient armies did not adapt to the water war, and the equipped ships had limited ability to deal with the waters.

In ancient times, the water in the Yellow River was wide and urgent, so it was very dangerous for big ships to cross the Yellow River, and the load of small ships was not suitable for fighting and transporting materials. If you cross the Yellow River and enter Guanzhong, you need to know the weather conditions at that time to avoid heavy rain or other conditions during driving. If the ship capsizes and is affected, it will also damage the troops. In ancient times, this kind of ship was steered by people on the one hand and sailed by the wind on the other, and it needed an experienced old captain at the helm. The army went out to fight and passed by. This time, it is not clear where there is undercurrent, where it is easy to run aground, where there are too many uncertainties such as rapids, and the local captain who knows the situation is not willing to participate in the war. After all, life was in danger at any time.

Even if someone can finally steer, pay attention to the wind direction and wind power in order to pass smoothly.

After these conditions are met, it is the condition of the ship itself. At that time, ships were mostly made of wood, which was very easy to catch fire. If the enemy throws fireballs at the hull in the middle reaches of the Yellow River, there is little possibility of life on board, so the enemy can defeat the attacker with no effort.

Therefore, if ancient people chose the Yellow River to enter Guanzhong, there were many restrictive factors. Most choose to attack Hanguguan or Tongguan.