Why didn't Zhu Yuanzhang pass on the throne to Judy, but from generation to generation?

Judy is neither the youngest son nor the oldest son, but Zhu Yunwen, as the eldest grandson of the emperor, conforms to the traditional succession order to the throne. In ancient times, the succession to the throne often followed the following order: the first eldest son was the first heir; No leader, no son, illegitimate son acceded to the throne, eldest son first. In this order, Zhu Yuanzhang, as the emperor, is the eldest son Zhu Biao.

There is no doubt that Zhu Yuanzhang trained Zhu Biao in full accordance with the standards of future successors. He never imagined that Zhu Biao had been a prince for more than 20 years. Although he was able to take charge, he could not support himself and died before he was forty. Zhu Yunwen, as the second son of Zhu Biao, always took care of his father when Zhu Biao was ill in bed. Zhu Yuanzhang saw everything in his eyes and kept it in his heart. He has hopes for Zhu Yunwen.

Speaking of Judy, according to the order of the throne, he has no chance to be emperor. Because when Zhu Biao died, besides Judy, there were also the King of Qin and the King of Jin. Even in Zhu Yuanzhang's eyes, Judy is stronger than the other two. However, according to the ranking, it is not Judy's turn to inherit the throne. If the throne is really given to Judy, then the king of Qin and the king of Jin will be released, and there will be disputes between the three brothers. This ending is not what Zhu Yuanzhang wants to see. After all, they are all their own sons.

In this case, Zhu Yunwen, the grandson of the emperor, is a good choice. Zhu Yunwen has read a lot of poetry books since he was a child, and he has a wide range of knowledge. He often loves the people with a kind and filial heart. Both the ministers in the palace and the common people spoke highly of him. It's a good choice to make Zhu Yunwen emperor, and at the same time, it avoids the disputes among the king of Qin, the king of Jin and the prince of Yan.