Cao Cao wanted to be called emperor, otherwise he would not have usurped the throne as king, so why didn't he directly call himself emperor, holding the son of heaven hostage and making the princes a double-edged sword. It is advantageous to allow Cao Cao to occupy an orthodox position, through the Son of Heaven, to give orders to all kinds of assassins, and to gather people's hearts and minds through the imperial court to attract the world's disciples. And Cao Cao, through the position of chancellor, actually controlled the entire Han Empire. On the downside, this gave Cao Cao a label, he was a supporter of the Son of Heaven, the Son of Heaven was around, unless he was willing to make enemies of the whole world, he would not dare to kill him easily.
At that time, although the Han Dynasty had declined, there were still many people who looked forward to the revival of the Han Dynasty and worked hard for it. Cao Cao saw through this, and he often claimed to be loyal to the Han Dynasty to cover up his purposes. He used the appearance of a loyal vassal of the Eastern Han Dynasty to win the hearts and minds of the people, and soon recruited many talents and soldiers. These soldiers were able to defect to Cao Cao because they believed that Cao Cao could help the Han Dynasty restore its rule. Therefore, under the weighing of pros and cons, Cao Cao chose to keep to himself and be satisfied with the current situation.
After Cao Cao seized the power in the north, his heart was still very inflated, and he also wanted to be called emperor, at that time, Yuan Shu, the military strength and financial resources were comparable to Cao Cao,Thinking that he could replace the Han Room and replace it, but the result was that he was hunted down and killed by various princes, and the rebellion of the people, Yuan Shu's ending made Cao Cao like a basin of cold water, he understood more clearly, when there was no complete unification of the world, everyone wanted to have the heart to get a piece of heaven and earth, whoever called the emperor first, who made enemies in all directions, and if he did not die, he would not die.