Not actually exclusive.
Here in Indonesia, Mizuno badminton exist but not easily available. Maybe just 1 or 2 store sell Mizunos on some big city & their selection also limited to some model only, unlike the big 3 that is available wide spread on every badminton shop.
Probably, the right term would be Mizuno high end exclusively made in Japan which makes their high end racket pretty expensive similar to Yonex JP version.