Interesting tweet from Takashi Mochizuki:
According to Famitsu, Nintendo sold 878,063 units of Switch between Nov. 27 and Dec. 24 in Japan, making since-launch total at 3.3 million units. Japan accounts for 25% of Nintendo's total Switch hardware/software sales pic.twitter.com/0Z8gdofUhd
Discussion in the tweet below seems to suggest that the Switch could outsell the WiiU faster than expected. Famitsu says the Switch sold 303,504 units Christmas week.