How did gate towers at Great Wall passes serve soldiers?

Gate towers at the Great Wall of China passes served as essential military infrastructure, functioning primarily as watchtowers and command posts.1

Constructed of wood or a combination of brick and wood, these towers were typically one to three stories high and positioned atop the gate of a pass. From this vantage point, soldiers could monitor the surrounding area for potential threats and oversee defensive operations. In addition to their role in surveillance and command, the gates themselves provided a strategic exit point, allowing the garrison to launch counterattacks against raiders or deploy patrols to secure the frontier.1