People like the trench of infantry and crossbowmen all walk on foot. Cavalry is a bit special, because cavalry has horses, but the essence is the same. They all climbed mountains and marched on foot.

But it was also divided into military regions in ancient times. For example, when there is a war in the northwest frontier, the government will send troops stationed in Xinjiang to fight, and the commander-in-chief will be appointed by the emperor. If there is a war in the northeast frontier, troops stationed in the three northeastern provinces will be dispatched to participate in the war.

So in ancient times, efficiency was also emphasized. Where there is a war, local troops are sent to resist. If the resistance is weak, the government will send reinforcements from other areas. It would not be said that the war in the northwest was an expedition by the Northeast Army, and the troops must have been exhausted on the road before they arrived at the battlefield.