Okinawa has its own language. And was assimilated by Japan in the 19 century. Kansai is not a recently added province. Then just look at the policies. How many were built to assimilate Kansai, how many were built to assimilate Okinawa. So difference are bigger that you may think. But i'm trying tell anybody if they are Japanese or not. Japanese people cannot say from one hand that they very different from Chinese people and say Okinawa people are very close to Japanese people. That just doesn't make sense.