In 10 BC, Zi Ying, king of Qin, surrendered to Liu Bang, and the Qin Dynasty perished. Later, Liu Bang accepted the dissuasion of Fan Kuai and Sean, returned to the army, and made a pact with the Qin people for three chapters, which won the favor of the Qin people. Later, Xiang Yu entered Xianyang, killed Zi Ying, plundered the treasure, set fire to Xianyang Palace, claimed to be the overlord of Chu, and then enfeoffed his ministers, and already regarded himself as the co-owner of the world.
Because Xiang Yu was afraid of Liu Bang's reputation, in order to trap Liu Bang, he deliberately enfeoffed Liu Bang to the Bashu Hanzhong generation and called Liu Bang Hanwang. In order to curb Liu Bang's influence, Xiang Yu also sealed the land in Guanzhong promised by Wang Huai to three Qin generals. It can be said that Liu Bang's fiefs at that time were only Bashu and Hanzhong, which were basically similar to the Shuhan regime that later occupied Yizhou and Hanzhong.
After Liu Bang became Hanwang, he avoided fighting with Xiang Yu because of his lack of strength at that time. Later generations praised Liu Bang for avoiding fighting with Xiang Yu at this time, but he lost his edge. Later, with the help of Xiao He, Sean and Han Xin, Liu Bang's Han army became stronger and stronger. He and Xiang Yu discussed the division of Chu and Han.
After that, Liu Bang attacked Xiang Yu behind his back, making Xiang Yu retreat to Gaixia. At that time, Liu Bang disintegrated the morale of the Chu army by means of being besieged on all sides, causing Xiang Yu's men to be distracted and unable to fight again. Under such circumstances, Xiang Yu had no choice but to break through, but when he broke through to Wujiang, he felt ashamed to face his elders in Jiangdong, so he committed suicide in Wujiang.
When the Shuhan regime occupied Yizhou and Hanzhong, the concept of whether the Shuhan court was fighting or defending was different from that of Liu Bang at that time. In 226 AD, forty-year-old Cao Pi died of illness, and Cao Cao proclaimed himself emperor. At that time, some people in the Wei court thought that Zhuge Liang could be sent to destroy them in Hanzhong. Cao Cao, who just ascended the throne, was very moved by this suggestion.
Sun Tzu, on the other hand, thinks that the terrain in Hanzhong is dangerous, which will cause chaos and cost a lot. Therefore, it is better to let the general guard the dangerous place. As long as Wei's national strength is strong, it will naturally surrender without a fight.
It is precisely because Zhuge Liang and others think that in the long run, the gap between Shu Han and Cao Wei will get bigger and bigger, so they will not hesitate to attack Cao Wei with the power of one country. Since the territory occupied by Liu Bang at that time was similar to that occupied by Shu Han at this time, why did they face completely different choices and analyses?
First of all, Liu Bang had kept his position secret at that time. Because Xiang Yu didn't send his own people to stay in Guanzhong at that time, he handed them over to three generals, which led Liu Bang to easily capture Guanzhong, while Shu Han only occupied Bashu and Hanzhong at that time, but did not occupy Guanzhong. So Zhuge Liang had to send troops to the Northern Expedition several times in order to occupy Guanzhong like Liu Bang.
Secondly, it is difficult for other generals in Xiang Yu Group to be immune to himself, so that after Liu Bang captured Guanzhong, he even hit Pengcheng in a short time, forcing Xiang Yu to turn around and attack Liu Bang. During the Three Kingdoms period, Cao Wei had many excellent generals. Therefore, it is impossible for Shu Han to achieve Liu Bang's achievements in those years, and even General Guan Yu can't directly attack Xudu.
The most important thing is that Liu Bang did not evade the war against Xiang Yu at that time. What Liu Bang did at that time was to attract the main force of Xiang Yu, let Han Xin explore the territory in the north, Ying Bu rebel in the south, and Peng Yue harassed in the rear, which made Xiang Yu superior and unable to resist, and was eventually consumed by Liu Bang. If Shu Han didn't send troops to the Northern Expedition, he could only watch Cao Wei, who occupied nine times out of ten in the world, grow stronger and stronger, and finally crush Shu Han with national strength.
Although Zhuge Liang has the ability of Xiao He, Guan Yu is not as good as Han Xin, but he also has the courage of Ying Bu and Peng Yue. Although Fa Zheng is not as good as Sean, he can also advise Liu Bei to occupy Hanzhong. But at that time, Liu Bei faced Cao Cao, who had numerous military commanders and counselors, instead of Xiang Yu, who was headstrong. Therefore, Shu Han at that time was doomed to be unable to replicate Liu Bang's past success.