User blog comment:Kat342/Theories of Why China's Hair is So Long.../@comment-2140341-20100814161621

Here's the reason(in my opinion) during one of the dynasties, most likely the Qin or Shun the emperor ordered men to put their hair within the next ponytail in 10 days or they would be beheaded. This was a loyalty test, so the king could see who was a loyal subject and who was not. So yes, this is traditional.