The collapse of the Qin Dynasty meant the failure of the county system, and after the rebellion of Chen Sheng and Wu Guang, the nobles of the Six Kingdoms had already restored the country, and basically quickly controlled their original territory. After the death of Chen Sheng and Wu Guang, this was even more so, and even the State of Chu, which first raised the banner of anti-Qin, returned to the original state of nobility as kings, and some of the princes established by Chen Sheng were soon killed, generally returning to the state before qin destroyed the Six Kingdoms.
By the time Liu Bang and Xiang Yu were ordered to go north to rescue the Zhao State, it was already completely the pattern before the Six Kingdoms, zhang Handan, after defeating the Chu army and killing Xiang Liang, basically followed the route of the previous Qin annihilation of the Six Kingdoms, and continued to attack to the east, as long as the Zhao State, which was relatively strong at that time, there was no main force in the Kwantung countries to resist Qin, but in the Battle of Julu, Xiang Yu broke the cauldron, defeated the Qin army, and forced Zhang Handan's 200,000 people to surrender, and the situation was reversed.
Later, according to the agreement of the King of Chuhuai, the first to enter the pass was the king, Xiang Yu led the army to confront the Qin army of Zhang Handan, and Liu Bang led the army to directly attack the Qin guanzhong homeland, and finally successfully broke through the Qin army's defense line and entered Guanzhong, the Qin prince infant surrendered, and the Qin state perished. According to the previous agreement of the King of Chu Huai, then Liu Bang should be the King of Qin. However, Xiang Yu was not convinced, and led his troops to defeat the defenders sent by Liu Bang to Hangu Pass, and demolished Hangu Pass, entered Guanzhong, burned it on a large scale, and then assembled the princes and adjusted the fiefs of various countries.
Because the main purpose of Xiang Yu's adjustment of the fiefdoms of various countries was to weaken other countries, so the original countries were split, and what he left to himself was the more core territory of the Chu state, he himself was the overlord of Western Chu, so as soon as he returned to the capital City of Pengcheng, the other princely states began to attack each other, and the world was in chaos again, while Xiang Yu first led his troops north to attack the State of Qi, Liu Bang took the opportunity to return to Guanzhong from Hanzhong, destroyed the Three Qins, sent Han Xin to lead troops to attack the Zhao State and the Qi State's homeland, and he himself led his troops straight to Pengcheng.
In the process of the Chu-Han conflict, the princes of various countries also chose sides between Xiang Yu and Liu Bang, Liu Bang on the one hand to win over those princes who opposed Xiang Yu, while eliminating the princes who still sided with Xiang Yu, and finally even Xiang Yu's own princes such as Yingbu, the king of Jiujiang, betrayed Xiang Yu, and the rebellious Xiang Yu was finally defeated by Han Xin in the Battle of Xiaxia, and he himself committed suicide after fleeing to the Wu River. The Chu-Han rivalry ended in the victory of Liu Bang, and at this time a large number of former princes were still retained, as well as han xin and other princes who he himself crowned as the king of Qi.
Therefore, after defeating Xiang Yu, Liu Bang then began to attack the king with different surnames, and finally eliminated the kings of different surnames represented by Han Xin, Yingbu and Peng Yue, and sent his own sons and nephews to various places as princes to guard the town, and agreed that no king should be kingless other than Liu, otherwise the whole world would attack him. At this time, the princes that Liu Bang divided into were larger in the southeast, and most of the princes' territories were only the size of the territory after the previous Xiang Yu was divided.
After Liu Bangding's capital was Guanzhong, the Guanzhong region that could be directly controlled and some areas in the Central Plains, mainly some parts of Korea and the State of Wei, were basically controlled by the central government, that is, the county system, while other places where the central government was still out of reach at that time retained the sub-feudal system, but the princes were all nephews of the Liu clan to maintain the stability of the whole country. That is to say, the coexistence of the feudal system and the county system in the early Han Dynasty was not designed by Liu Bang, but a problem left over from history.