Why did Zhu Yuanzhang, the founding emperor of the Ming Dynasty, return the imperial power to his grandson Zhu Yun?

Zhu Yuanzhang liked Prince Zhu Biao very much and wanted to pass on the throne to him. He spent a lot of effort on Zhu Biao. In his view, the world is set, and the country needs sandwiches, which cannot be passed on to Judy, the prince who conquered Anbang and threatened the country. However, when Prince Zhu Biao died young, Zhu Yuanzhang was very depressed. He not only buried Zhu Biao in the Ming Tombs, but also made Zhu Yunwen, the son of Zhu Biao, the great-grandson of the emperor. This not only expressed the grief for Zhu Biao, but also passed the throne to the descendants of De. According to tradition, Prince Zhu Biao died young, so he passed it on to Zhu Yunwen, the eldest son of Zhu Biao.

Originally, the eldest son had both ability and political integrity, while the second and third sons didn't grind people at all. If they are not too smart, they will be too stupid to undertake this great task, while Judy, the fourth son, is brilliant in military exploits, but not greedy for merit, which is good for several brothers! Originally, I wanted to pass the throne to the fourth prince, but a fortune teller said Judy would take away his world. Therefore, Zhu Yuanzhang didn't have four emperors. His yearning for his eldest son and his love for his grandson made Zhu Yunwen! !

Mao thinks his son is too disobedient and may be too ambitious. If he is too similar, what is needed to govern the country is "forgiveness."