Kinect may be the "fastest-selling consumer electronics device in history", but it has achieved that great feat almost entirely outside of Japan.
Xbox Japan's Takashi Sensui revealed that Kinect had only sold 90K units in Japan as of January. In contrast, Kinect was able to sell over that amount, 133,333 units per day, in its first 60 days on the market worldwide.
This could be due to the poor reception the Xbox 360 has had in general in the region, or it might be due to many Japanese people living in small, cramped apartments where there isn't enough space for Kinect to work properly.
I guess giving out measuring tape (see picture above) at Kinect kiosks was not the best idea after all.