Sima Yi's subordinates wanted to station their camp north of the Wei River, but Sima Yi said: "Many civilians have gathered at the south of the Wei River. That will definitely become a hotly contested location." Sima Yi then led his troops across the Wei River and took up his position with his rear facing the river, and began constructing fortifications. He additionally said: "If Zhuge Liang is brave enough, he'll move out from Wugong County and head eastward in the direction of the mountains. If he moves west to the Wuzhang Plains, we'll have no worries." Around that time, the Wei emperor, Cao Rui, became worried, and so decided to send the general Qin Lang to lead 20,000 infantry and cavalry as reinforcements to join Sima Yi.