The battle of Haochih (206 BC) was the second victory in Liu Bang’s (founder of the Han dynasty) invasion of the kingdom of Yong, the first step in the civil war between Liu Bang and Xiang Yu.
Liu Bang and Xiang Yu were the leading commanders in the war that had ended the Qin dynasty. Liu Bang had been the first of the rebel commanders to occupy the Qin heartland, and had expected to be made king of Qin after the war, but instead he was given the kingdom of Han, to the south and south-west of Qin. Qin itself was split into three, with the southern part becoming the kingdom of Yong, ruled by Zhang Han. Xiang Yu, the senior rebel commander, attempted to establish himself as over-king, with eighteen subordinate kings.
This system very quickly collapsed. Liu Bang decided to take Qin by force. He launched a surprise attack on Yong, winning a first victory at Ch’ents’ang. In the aftermath of this defeat Zhang Han retreated to Haochih. Liu Bang followed, and won a second victory at Haochih. Zhang Han then retreated to Fei-ch’iu. Early in 205 the kings of the remaining two kingdoms, Sai and Di, submitted to Liu Bang, but Zhang Han held out into the summer of 205 BC.