In the pitch-black night, Gu Peiyuan and He Nu looked at the distant tower, which was the enemy commander's residence. The exact number of people inside was unknown.
He Nu and Gu Peiyuan, lacking manpower, did not choose to take action immediately but continued to wait for the right moment.
While waiting, the two remained hidden, trying hard to record and study the enemy's activities across from them—how they changed shifts, roughly how many minutes between each shift, estimating how many were on duty...
Because the two dared not get too close for fear of being discovered by the enemy, they observed from afar, which greatly affected their observation. Most of the time, they couldn't see any figures. Only when the enemy shifted the guard, a light would flash by, and they could see the vague silhouettes on the opposite city wall in the dim light to gauge the number of enemies on the wall.
