Autumnal Equinox Day (秋分の日)

The Autumnal Equinox Day is the day when the autumnal equinox occurs.

Although it is often said that this is one of two days a year when "the lengths of day and night will be equal," actually, the day is longer than the night. For details, see the Autumnal Equinox.

National Holidays
It is one of the national holidays in Japan. It was established by the Act on National Holidays that was promulgated and went into effect in 1948.
According to the Act, the purpose of the holiday is 'to respect our ancestors and remember the deceased.'
Until 1947, it was a holiday called "shukikoreisai" (imperial ceremony of ancestor worship formerly held on the autumnal equinox).

On this day, 'Shuki Higan-E' (Autumnal Equinox Service) is held at each sect of Buddhism in Japan and many people visit their family graves regardless of their sects.

Date
The Autumnal Equinox Day falls around September 23 of each year. Under the Act on National Holidays, it is set as 'the autumn equinox,' when the earth passes the Autumnal Equinoctial Point (Japan time). The day is decided at Cabinet meetings based on the booklet called " Calendar and Ephemeris "created by the National Astronomical Observatory of Japan and is announced in an official gazette as of the first weekday in February of the previous year. Therefore, the dates of the Autumnal Equinox Day two years and beyond have not been fixed; however, days other than autumnal equinox day obtained by an astronomical calculation has never been set as the Autumnal Equinox Day so far. In addition, based on the astronomical calculation, the Autumnal Equinox Day falls on September 23 every year until 2011. However, after that, it falls on September 22 on leap years and September 23 in other years until 2044.

The influence of applying the Happy Monday System
Due to the revision of the Act on National Holidays (so called the "Happy Monday System"), Respect for the Aged Day which used to be celebrated on September 15 was changed to the third Monday in September from 2003. Because of the change, Respect for the Aged Day came to fall on September 21 or 20 in some years.

When September 21 or 20 will be the Respect for the Aged Day and September 23 or 22 will be the Autumnal Equinox Day, the day sandwiched between the Respect for the Aged Day and the Autumnal Equinox Day (22 or 21) is regarded as a national holiday due to a provision of the Act on National Holidays. In this case, starting from the Sunday, the day before the Respect for the Aged Day, the weekend will be a four-day weekend (a five-day weekend for those who have a five-day work week). Because of this, it is said that 'the second Golden Week' (or since the Respect for the Aged Day is included, it might be called 'Silver Week' as opposed to the Golden Week [a collection of spring holidays in Japan]) may be created.

It is also expected that the first year when the above case can be applied will be 2009 and next year will be 2015 (in both years, the Respect for the Aged Day will be September 21 and the Autumnal Equinox Day will be September 23), unless the Act on National Holidays regarding the both holidays (the Respect for the Aged Day and the Autumnal Equinox Day) and the national holiday will be revised in the future.

In 2020, it is expected that the Respect for the Aged Day will fall on September 21 and the Autumnal Equinox Day will fall on September 22 (according to the astronomical calculations). Since it will be a two-day holiday, the above case will not be applied. In the next year of 2021, it is expected that the Respect for the Aged Day will fall on September 20, but the Autumnal Equinox Day will not fall on September 22 but on September 23. The above case will also not be applied to the year. In 2032, September 21 will fall on a national holiday because the Respect for the Aged Day will fall on September 20 and the Autumnal Equinox Day will fall on September 22.

Until 2099, the following years meet the condition mentioned above:
The pattern of September 19 - 23: year 2009, 2015, 2026, 2037, 2043, 2054, 2071, 2099
The pattern of September 18 - 22: year 2032, 2049, 2060, 2077, 2088, 2094
(Formally, the decision will be announced in an official gazette as of the first weekend in February of the previous year.)

[Original Japanese]