This is a point of contention for Japanese historians. For those who believe in 大和説 (yamato theory), 邪魔臺国 is part of Yamato polity that started in the east. In contrast, 九州説(Kyushu theory) theorizes that 邪魔臺国 is just a small nation in Western Japan. No one really know for sure, but majority of the historians seem to believe in the Yamato theory.