산해관
On May 25, Li Zicheng deployed his men along the Sha River (沙河) a few kilometers west of the Shanhai Pass fortifications. He could observe the battlefield from a nearby hill, accompanied by two young Ming princes whom he had taken hostage. Wu Sangui assigned two trusted lieutenants to the defense of the northern and western walls of Shanhai Pass, and let gentry-led militia protect the eastern wall of the garrison. He then deployed his troops near Sha River to face Li Zicheng's army.