Subways run all night on the New Year's Eve
Ok, ok, don't blame us for Tokyo's not having 24hrs public transportation. On this special day, most JR lines and subways will run all night. They come less frequently than usual, but come every 20-30 minutes, not that bad.
This, I believe, is originally meant to serve those who go to shrines and temples to do the New Year's visits (hatsumode), but is also good for our guests who go nightclubbing for countdown parties on the New Year's Eve. You can come back to the hostel or jump from a party to another by subway, avoiding taking a taxi.
Sakura staff is not the only one who will work all night on the day...