Similar to how Bavarians or Prussians are distinct, yet both considered German?
EDIT: By Japanese Empire I was meaning the empire after the Meiji Restoration. I suppose I was thinking regionalism between 1300 and 1868.
Further clarification: For example, how different were the people in say Kanto compared to those in Shikoku in this time period?
creation of the Japanese Empire
Does this means that of the fifth century before?
If you so,the answer is Yes.
Yamato dynasty period had the elements of the Union State.Including Chikushi(Now in Fukuoka),Kibi(Okayama),Owari(Nagoya),Echizen(Fukui).
They made a marital relationship with the Daiou(ancient king) clan.
Each local area has been observed that independence was high in the current research(mainly Kouichi Mori).
They often intervened to throne when the Daiou replaces.
Becoming the seventh century they have been placed under the control eventually.