In autumn, Jiang Wei led Shu forces to attack the Wei-controlled Yong Province, had two fortresses constructed at Qushan (麴山; southeast of present-day Min County, Gansu), and ordered his officers Ju An (句安) and Li Xin (李歆) to guard them. He also contacted the Qiang tribes and requested assistance from them in harassing the commanderies in Yong Province. Guo Huai discussed with Chen Tai, the Inspector of Yong Province, on how to deal with the Shu invasion. Chen Tai said: "The fortresses at Qushan may be well-defended, but the roads leading into Shu are difficult to travel, so they will require a sufficient amount of supplies. The Qiang tribes are worried about this weakness of the Shu army, so they may not be willing to help Shu. If we surround the fortresses and attack them, we can easily capture them. Even if Shu reinforcements arrive, the dangerous mountainous terrain will cause them to be worn out."