After Cao Cao defeated Yuan Shao at the Battle of Guandu, it took a few years to completely pacify the four prefectures of Hebei, at this time he had become the strongest prince in the world, looking at the strong soldiers and strong horses, Cao Cao felt that the world had been in chaos for a long time, and now it was time to restore people's livelihood. So he led a large army to the south, and his goal was to first take Jingzhou and then Jiangdong, and finally unify the world.
Soon after Cao Cao's southern expedition, Liu Biao of Jingzhou directly fell ill and died, and Liu Biao's heir Liu Qi directly took Jingzhou to surrender to Cao Cao, and at this time Cao Cao seemed to have seen the moment when the world was pacified and began to flutter. It was said that the arrogant army would be defeated, And Zhou Yu and Zhuge Liang first used straw boats to borrow arrows to prepare for confrontation, and then arranged for Huang Gai to use the bitter meat meter to paralyze Cao Cao, at this time Pang Tong was still suggesting that Cao Cao connect the ships with iron cables. The liusun alliance, which was ready for everything, used only one battle of Chibi to shatter Cao Cao's dream of unifying the world, and thus began to enter the period of three divisions of the world.
After Cao Pi usurped the Han dynasty as emperor, Cao Wei sat on the land of Kyushu, and the Kyushu here was not the Kyushu in the Yugong-Kyushu, but the Kyushu of the thirteen states of the late Han Dynasty. After Emperor Wu of han succeeded to the throne, he divided the world into thirteen states and arranged for Shi Shi to be the highest administrative governor, and the establishment of the Eastern Han Dynasty continued this setting until the current Three Kingdoms period.
At this time, the State of Wu had a place called Yangzhou in Jiangdong, as well as a vast land of Jiaozhou, jingzhou occupied the four counties of Jingnan, and the area around Xiangfan in jingbei was occupied by Cao Wei. The forces on the Shu Han side were even weaker, only In Yizhou and also had to guard against the rebellion of the foreign tribes in Southern Central, when Liu Bei died, the barbarian king of Southern Central Meng Yu once rebelled, and finally was taught by Zhuge Liang with a large army to be able to divide and defend himself. But Cao Wei had such a big advantage, why did he postpone the unification time by fifty years?
First, the Battle of Yiling made the forces on both sides of the Shu Han and Eastern Wu completely see the situation. When Guan Yu was defending Jingzhou, he led a large army to defeat Cao Ren stationed in the Xiangfan area, and even completely annihilated the reinforcements sent by Cao Cao, seeing that Xiangfan was about to take down, Sun Quan actually sent Lü Meng to secretly attack Jingzhou.
Lü Meng did things very cleanly and neatly, not only taking the jingzhou area originally controlled by Shu Han, but also sending an army to annihilate Guan Yu by the way, and Liu Bei's side naturally could not bear such a huge loss, and Liu Bei launched the Battle of Yiling despite everyone's persuasion. Although Eastern Wu later won the war, it also made both Shu and Wu realize that if they were to fight so hard, they might be broken by Cao Wei one by one, so the two families reconciled to jointly resist Cao Wei. The Shu Han side stationed heavy troops in Hanzhong, the Eastern Wu garrisoned heavy troops in Lujiang, and the Cao Wei side fell into a two-front battle situation, and it was difficult to unify the world for a while.
Second, the Sword Pavilion Xiongguan and the Yangtze River Graben are easy to defend and difficult to attack. Li Bai, a famous poet of the Tang Dynasty, once wrote that "the sword pavilion is magnificent and Cui Song, one husband is the pass, and the ten thousand people are not open" lamented that the road in Shuzhong is very rough. Looking at the history of various dynasties, we can also find that no matter which era the world is in chaos, there will always be separatist forces in this part of Yizhou, such as the great chaos in the world at the end of Qin, Liu Bang, who was born in Yizhou, used Yizhou as a base to smelt weapons, burned the boardwalk to declare that he did not interfere with the Central Plains, but secretly sent the general Han Xin to send troops to Chen Cangdao to occupy Guanzhong.
For example, Meng Zhixiang during the Five Dynasties and Ten Kingdoms period, he took advantage of the great chaos in the world to divide here and establish Hou Shu, and because the Shu Dao was too difficult to walk, the forces that were divided here were not easy to be suppressed. And Jiangdong has the Yangtze River Graben is also a natural barrier, cao cao had the potential to sweep the world, but because his soldiers are mostly northerners who are not good at water warfare, although the Yangtze River is only a river but it has also become an insurmountable gap for Cao Wei, Cao Wei wants to break the situation can only wait for shu Han and Eastern Wu internal changes.
Third, shu han and eastern Wu have no shortage of capable people. When Cao Pi wanted to launch a campaign to unify the world after succeeding to the throne, he specially consulted the opinion of Jia Xu, who was known as the "poisoner", at that time Jia Xu was already Cao Wei's lieutenant, Cao Pi originally thought that he would get a series of plans from Jia Xu, but Jia Xu surprised him.
Jia Xu told Cao Pi: "Although Wu and Shu were small in the country, relying on the mountains and rivers, Liu Had Great Talents, Zhuge Liang was good at governing the country, Sun Quan knew the truth, Lu Yi saw the military situation, defended according to dangers, and it was difficult to plan against the rivers and lakes. In the way of using soldiers, we will win first and then fight, and we will judge the enemy and judge the generals, so we will do everything in our power. The courtiers stole the materials and the courtiers, unprepared, and the power was right, although they came with heavenly power, they did not see the momentum of perfection. ”
Even Jia Xu, the initiator of the great chaos in the world, believed that Cao Wei's qunchen could not defeat Shu Han and Eastern Wu, and the chances of victory were very slim. Later, Cao Pi did not believe in evil, and when he sent out his troops, it was exactly as Jia Xu expected, and the Wei army lost a mess.
Fourth, the power struggle of the Wei ruling clique was fierce. At that time, Cao Cao should have implemented the policy of "holding the son of heaven hostage to order the princes" when he took Emperor Xian of Han to the capital of Xuchang, but the imperial court was still Liu's, and the emperor was also Liu Xie, the emperor of Han Xian. However, after Cao Cao's death, Cao Pi directly stood on behalf of the Han Dynasty, which directly caused dissatisfaction among the ministers loyal to the Han Dynasty, and directly triggered the struggle within the Cao Wei ruling clique, and it was at this time that the Sima Yi clan rose.
Originally, the Wei Ming Emperor Cao Rui had already balanced internal relations during his reign, but he did not expect that Sima Yi had launched a coup d'état after Cao Rui's death to steal Cao Wei's Jiangshan, and this time the turmoil was even greater than before, and there were three princes who announced their independence from Sima Shi's rule alone, namely Wang Ling of Shouchun, Meng Da of Shangyong, and Gongsun Yuan of Liaodong. Although Sima Yi resolved these problems during his tenure, Cao Wei became weak and unable to use troops against Shu Han and Eastern Wu on a large scale, and the road to unification was delayed for decades.