✔ 最佳答案
There's a holiday created in 1966, called "Taiiku no Hi" or "Health and Sport Day." It used to be October 10, the day of the opening of the Tokyo Olympics, but today, it is celebrated on the 2nd Sunday of October.
Here's an interesting site that gives you the list of holidays in Japan. May has the most number of holidays:-)
參考: I'm Japanese.