Thanks to the present Emperor's being born on December 23, we get a day off exactly when we need it. Right now. Today. In the midst of the rush to bring the year to a successful end.
The year-end gift-giving season in Japan is already over. If you have New Year holiday travel plans, they are already finalized. So it's not a day to run around on errands. It's a time out.
Happy Birthday! And thank you for the present.