I was looking at the website of the park but couldn't see any information if the park is open or not on January 1 or 2. Does anyone knows? Thank you
It does not say anything about their holidays in English and in Japanese. So, I guess it's open everyday.
The official park page says open seven days per week.
Open during winter. But sometimes it can be snowed off. Get the info by Facebook.
One daily thought the year:
One hours is displayed on top of the website everyday: