Based on the current install base and how previous Mario games performed Week 1 in Japan, I'd say around 200k minimum. It might do better since, aside from GT6 and possibly Lightning Returns, there's not much else in the way of big console titles that I'm aware of that have mass appeal to Japanese audiences. Japan still really likes Mario, as evidenced by Mario Galaxy outselling all but one PS3 games and NSMBWii being the best-selling game of the generation there (not counting handheld titles). Odds are, SM3DW will be the best-selling console title in Japan this holiday season, and should sell well over half a million copies before the end of the year.