…the Tong Pass, located in the east…
February 756 CE
…the Tong Pass, located in the east of the Central Plain, north of the Qin Mountains, south of Wei and Luo River, east of the Mount Hua and in between the three provinces of Shanxi, Shaanxi and Henan.
The pass is defended by the Tang general Geshu Han, who repels An Qingxu's attack.