It's hard to argue...

who merged whom. After all, Hans shaved their heads. That's why I said culture and tradition are evolving concepts - can you say after a western modernization and a bloody civil war, Japanese culture and tradition were terminated back in the 19th century? In the same token, Japan and Korea may have better preserved, to certain degree, more traditional Chinese culture (Tang and Song cultures indeed) - would you recognize them as "China" too?