You think Chinese never record those past flood for many century or think it's some kind of fabrication? They have certain discription like reaching certain level of some mountain and hill. The soil analysis can also determined the credibility of those few hundred years ago record.
If not, how do we manage to come to conclusions the legend of Yu is not a myth and the huge flood describe as true event?
According to legend, Chinese civilisation began around 4,000 years ago in the Yellow River basin, when an emperor called Yu the Great successfully managed to control a huge flood.
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