The battle of Chenggao (204 BC) was a minor victory won by Liu Bang while the main Chu armies under Xiang Yu were distracted by a defeat suffered by one of his other armies at Hsia-p’ei.
The main Han and Chu armies had been campaigning around Xingyang, close to the Yellow River, since 203 BC, with Xiang Yu raiding Liu Bang’s supply lines, and in particular a fortified road that connected Xingyang with the granary at Ao on the Yellow River. The fighting intensified in 204 BC when Xiang Yu became a formal siege of Xingyang.
After a few weeks Liu Bang managed to escape from the besieged city and withdrew to the west to raise a new army. He then moved to Yuan, south of Xingyang, where he fortified his position. Xiang Yu followed, reducing the pressure at Xingyang. The Han position improved even further when Xiang learnt that his armies in the east had been defeated at Hsia-p’ei (Wade-Giles). Xiang moved east to restore the situation there, leaving a commanded named as the old gentleman Zhong in charge at Chenggao.
Liu Bang responded by moving north, attacked and routing Zhong’s army at Chenggao. He made his base in the city, but when Xiang returned from the east Liu Bang found himself besieged in Chenggao, and for a second time had to escape through enemy lines to safety.