During the Three Kingdoms period, why didn't Cao Cao destroy Liu Bei first, but hit Jiangdong first?

Jiangdong area is the most suitable area for Cao Cao to March. It can be said that this is very sincere, but Liaodong is bitter and cold. The website is tasteless, but it has been abandoned. Zhang Lu and Liu Zhang in the middle of the Han Dynasty have been protecting themselves. Obviously, this is not a big problem for Cao Cao.

In a word, if we only look at Cao Cao's strength, we will be very close to reunifying the country. Why do you say that? According to the Han Dynasty, Cao Cao was the total territory of Guandu Campaign, including Jizhou, Qingzhou, Youzhou, Binzhou, and Yuan Shao originally occupied, in addition to Cao Cao, Yuzhou and Xuzhou. It can be said that Cao Cao accounts for more than half of the States in the world 13.

Besides, these areas were the center of the world at that time. You know, judging from the situation in China at that time, the development degree of the northern region was obviously higher than that of the southern region, which was mainly due to the relatively backward agricultural means, which directly led to the huge gap in productivity between the northern and southern regions at that time. Obviously, the northern region is more developed and has a larger population than the southern region. Therefore, Cao Cao, who occupied the northern region at that time, was the most promising person to govern and inherit the country.

After Cao Cao unified the north, he thought that the climate was Matang in the west, Sun Quan in Soochow and Gongsun Ferry in Liaodong, with Liu Bei as the most important. At that time, Liu Bei had no army and few cities. Only Jiangxia was an isolated city. In World War I, he was hunted by Cao Cao again. It can be said that Liu Bei was the weakest vassal at that time, and Cao Cao would not treat him as a big trouble.

At that time, Cao Cao chose to unify the south without any problems. After all, Marten in the northwest gave up, and his grandson Liaodong was already very fragile. Liu Zhang and Zhang Lu in the southwest also protected themselves, but the Taoist priest was worse than the sky, and Cao Cao finally failed, which made people sigh.