Mountain Day

Mountain Day (Japanese: Yama no Hi) is Japan's newest national holiday, established by the 2014 amendment to the Act on National Holidays. The amendment was Act No. 43 of May 30, 2014, effective in 2016 and first observed on August 11, 2016. It is one of 16 national holidays published by the Cabinet Office, Government of Japan with no sample or survey for all of Japan. It is a public day off closing government offices, schools and exchanges by convention, not the United Nations mountain observance on December 11.

Mountain Day recurs every August 11 as a calendar day in Japan Standard Time. The Cabinet Office publishes two-year holiday tables and a CSV starting in 1955, updated each February for the year after next. When August 11 falls on Sunday, the closest following non-holiday weekday becomes a public day off under Article 3(2). Changes require a separate Diet law, and the Cabinet Office then updates its tables and 16-holiday list with dates, Act text and holiday examples.

It has no components, only a two-part legal purpose.

• Opportunity to get familiar with mountains: encourages all ages to visit, learn about and consider mountains in summer holiday season.
• Gratitude for blessings from mountains: acknowledges daily benefits from nature, forests, water, mountain villages and national park mountains. The Cabinet Office points to the Forestry Agency and the Ministry of the Environment for events and mountain information.

The August 11 date is fixed by law but a separate special law overrode it for the Tokyo Olympic Games in 2020 and 2021. In 2020 Mountain Day moved to August 10, 2020, a Monday, while Marine Day and Sports Day also moved for that year only. In 2021 it was set to August 8, 2021, a Sunday, so August 9, 2021 became a public day off under the Sunday rule.

1. Fixed date: Article 2 defines Mountain Day as August 11.
2. Public holiday status: Article 3(1) makes national holidays public days off.
3. Sunday rule: If August 11 falls on Sunday, the closest following non-holiday weekday becomes a public day off. For example, a Sunday August 11 shifts observance to Monday August 12, while the legal name stays Mountain Day on August 11.
4. One-off override: Only a separate special law can move the date, as in the Olympic exception.