I was a student of Chinese at the DLI in Monterey in the early 80's. At that time, the professors all had to have received at least a masters degree at a mainland China university. One of them had a masters in history.
He said that the tribal legends of the Han and minority tribes tell of a constant south-easterly migration, back to the earliest identifiable threads.
Yes, tribes. It seems that at least before Mao took over, most Chinese people knew which tribe and sub-grouping they were part of.
I think it's the system of generation names that enable the Chinese to maintain links with their tribal and clan past ~ BTW, some cable systems carry a set of international channels that features shows originating in Big China. Most of them are about archaeological discoveries in recent years. Some fascinating stuff there. But FUR SHUR the Chicoms even buy into the Eastward Ho thesis now. Their oldest stuff is in higher elevations, further West and further North ~ where you could graze animals and control the tigers. They gradually move East and South as the Temperate zone develops and destroys old forests and the game the cats relied on.