The emperor used delayed fortune telling.

It was delayed by 19 days, because Zhu Gaochi died after 19 days. This fortune teller is called Yuan Xun, and he is very good at reading fortune. At that time, Zhu Gaochi said why he was only the son of heaven, but his son was the son of heaven. Yuan Xun said it was an act of God and he couldn't tell you, but Zhu Gaochi told Yuan Xun that if he didn't tell you, he would kill you. As a result, Yuan Xun said that I told you 19 days later. This is because Yuan Xun saw from Zhu Gaochi's face that Zhu Gaochi was dying, so he said that he would postpone it for 19 days.

Yuan Xun has a good face. At that time, he saw many people's lives and hit the nail on the head, so he became famous. Later, I told Judy that Judy looked like an emperor after she was 40 years old. As a result, Judy really succeeded in sitting on the throne after he was 40. Therefore, Judy trusts Yuan Xun's fortune-telling skills very much, which is why Judy always asks Yuan Xun for advice when she meets something.

When Judy became emperor, he hesitated about the heir. The oldest is Zhu Gaochi, but he is in poor health. Zhu is the second child, very much like him, and everyone likes him very much. So he asked Yuan Xun who could inherit the throne. Yuan Xun tells Judy that Zhu Gaochi is the son of a grandson, and this grandson is the son of a grandson, and this is the son of a grandson, and he is the son of a grandson. Therefore, Judy finally decided that Zhu Gaochi was the heir to the throne.

Only then did Zhu Gaochi want to learn from Yuan Xun why he was different from his son. However, Yuan Xun should be able to see from Zhu Gaochi's face that Zhu Gaochi's health is not very good and he can be a good emperor, but due to physical reasons, he won't be able to do it for long. Actually, it really is. Although Zhu Gaochi was regarded as a very good emperor in history, his reign was less than one year, which was really short-lived.