"This is such a shock to see the Xbox not doing well in Japan!" - Nobody ever, 2014.

Seriously though, the Xbox bombed in Japan, the 360 bombed in Japan, the XB1 is just following suit. Nobody with any vague notion of Microsoft's relationship with Japan expected anything less.

For a long time worldwide the 360 did better than the PS3, but in Japan the preferred console was never up for debate.