Qishan is a famous road from Longyou toward Guanzhong. After the northern memorials, Zhuge Liang’s armies often left Hanzhong in this direction. Ma Su lost Jieting on a flank of that road.
Later poetry treats the name as a synonym for the northern war. On a map, Hanzhong is the base, Qishan is the exit, and Chang’an is still north of the Wei. One march from Qishan does not arrive at Chang’an.