"The Chu River and the Han Dynasty were divided into two": After the peasant uprising broke out at the end of Qin Dynasty, Xiang Yu (overlord of the western Chu Dynasty) and Liu Bang (Hanwang) fought for the world, and the two sides fought fiercely for more than ten months. Thanks to the support of Zhonghe Shu, Liu Bang gradually gained the upper hand, while Xiang Yu lacked troops and food, so it was difficult to compete with the Han army. Under the mediation of Duke Hou, Xiang Yu and Liu Bang reached an armistice agreement: Chu and Han took the gap (now Xingyang, Zhongmou and Kaifeng in Henan) as the dividing line, and the east and west were divided. After the agreement was reached, Xiang Yu returned Liu Bang's father and wife.

Pronunciation: Chu River is divided into two parts (China)

Interpretation: Taking the gap as the boundary, the west is Han, Liu Bang is Hanwang, the east is Chu, and Xiang Yu is the king of Chu.

Geographical location: According to records, the historical dividing line between the Chu River and the Han Dynasty is at the ancient elevation, Xingyang and Yuzhou. It is bordered by the Yellow River in the north, Kuangshan in the west, the plain in the east and Songshan in the south, which is a battleground for military strategists in past dynasties. In the summer of 205 BC, Xiang Yu defeated the Han army in Pengcheng (now Xuzhou, Jiangsu), and Liu Bang retreated to Xingyang. Since then, the two armies of Chu and Han have launched a two-year confrontation in Xingyang. In 203 BC, Liu Bang sent troops to attack Gaoping and Chu. Commander Cao Qian couldn't stand the repeated calls of Sergeant Liu Bang at the city gate, so he angrily left the city and wanted to cross the Si Shui to fight the Han army. When the ship reached the river, it was defeated by the Han army. Cao regretted it, knowing that he was ashamed to see Xiang Yu, so he committed suicide and died. Liu Bang successfully captured the elevation and prepared all kinds of weapons for An Lushan. When Xiang Yu learned that the elevation had been captured, he immediately sent troops to rescue him. In order to force Liu Bang to surrender, Xiang Yu dragged his captured father to Zhaoguangwu Mountain (now Wang Ba City) in the east of the city, and threatened Liu Bang across the river: "If you don't surrender early, I will boil your father to death." Liu bang pretended to be calm and said, "When we attacked Qin together, we vowed to be brothers. My father is your father. If you want to cook our father, don't forget to give me a bowl of broth. " Xiang Yu became more angry after hearing this and decided to kill Liu Taigong. At the urging of Xiang Bo, "Taigong survived". However, Liu Bang couldn't seal the city, so he sent general Han Xin to copy the back road of Chu Army and occupied Hebei and Shandong regions. Due to the lack of food and soldiers, Xiang Yu had to be forced to put forward the requirement of "dividing the world, cutting the gap to the west for Han, and cutting the gap to the east for Chu". In this way, history has made the gap become the "Chu River Han boundary".