函谷关
In late 207 BC, Liu Bang's rebel army conquered Wu Pass and seized control of Guanzhong and the Qin capital Xianyang. The last Qin emperor Ziying surrendered to Liu Bang, marking the end of the Qin dynasty. After occupying Xianyang, Liu Bang gave strict orders to his men, forbidding them from looting and pillaging the city and harming the civilian populace. Liu Bang also sent troops to garrison at Hangu Pass to block Xiang Yu from entering Guanzhong. Around the time, Xiang Yu's force had just defeated a Qin army led by Zhang Han at the Battle of Julu. When Xiang Yu arrived at Hangu Pass, he was displeased to hear that Liu Bang had already occupied Guanzhong, so he attacked and conquered the pass, pushing on to west of Xishui (戲水). Liu Bang and his army were based in Bashang (霸上) then. The strengths of Xiang Yu and Liu Bang's forces then were estimated to be 400,000 and 100,000 respectively.