The Yakuts did not come from the Xiongnu? I am shocked...
The Xiongnu were the bad asses of the steppes. The Yuezhi(sp) were the top dogs until the Xiongnu split them into the greater and lesser Yuezhi and the lesser Yuezhi migrated away and are probably the people we call Schytians.
The greater Yuezhi were assimilated by the Xiongnu and warred with the Han Dynasty and the Han finally defeated the Xiongnu. The Great Wall Of China was begun to keep out the Xiongnu. The Yuezhi were a Caucasian tribe and some believe the Xiongnu were also or at a minimum a mixed race group.
It is my opinion that the Hakka ('the guests') were a mix of all these racial groups and eventually migrated all the way across China after a serious drought in the north. Some migrated toward Europe and may be the Picts of Scotland(?).
I was flabbergasted!
Gehsundheit.