I was worried I might get stuck with my 7 night cert, but found a week around Christmas. Rate is for 2 people it seems, so for our 2 sons it will be an extra 5,000 per person per night, so ¥70,000. Still, ¥10,000/night plus the cost of of points I used for the travel package works out to be perhaps ¥20,000, not bad for a ¥35,000 room.

Just need to cross my fingers and hope for snow...