Di Ku is the nephew of Zhuan Xu and the great-grandson of the Yellow Emperor. It may also be because his sage Zhuan Xu passed the throne to Di Ku. During Di Ku's administration, he also made great achievements, managed the country well and left many achievements.
Zhuan Xu is the grandson of the Yellow Emperor. Because of his outstanding talent, the Yellow Emperor skipped Zhuan Xu's father's long bow and directly passed the throne to Zhuan Xu. But Zhuan Xu doesn't seem to have left any great achievements or stories. On the contrary, his nephew Di Ku's grades are not bad.
Put these three people together and say that Yao is the son of the great-grandson of the Yellow Emperor because of their chaotic relationship. After death, it was no problem to pass on the throne to his son, but something went wrong with Shun, and Yao passed on the throne to Shun.
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Shun, the ninth great-grandson of the Yellow Emperor, was four generations later than Yao. If you have early childbearing and late childbearing, it is ok to catch up with four generations. Shun was later passed on to Yu, but this Yu is also the great-grandson of the Yellow Emperor and the same generation as Yao's father.
It's really a little unreasonable. Of course, it's hard to prove it after too long. Now people say that Yao passed on the throne to Shun, and Shun passed on the throne to Yu, or that they did not simply pass on the throne, but had a relationship of seizing power.