C121 Xiliangguan

West Cold Gateway, a grand barrier between Liangzhou and Zhongzhou.

Guan Xi was for the Liangzhou, Guan Dong was for the Zhongzhou. If the First Dynasty were to advance westward, then the first thing to do was to take down the West Cold Gateway.

But since there had been no war for who knows how many years, other than that imposing tall building with the city walls