Nikon now has the top market share in Japan:
"In April, Nikon won the monthly top share for the first time in terms of sales volume of full-frame mirrorless cameras. In this category, Sony has always been at the top. Since the release of the "α7" in November 2013, Nikon has only been dethroned four times in the 150 months since its first release."
Source: Bcnretail via NikonRumors