The Vernal Equinox Day (春分の日)

The vernal equinox (the spring equinox) is the day when the vernal equinox occurs.

It is often said that the length of daytime and nighttime becomes the same, but actually the daytime is longer. See the vernal equinox for details.

National Holidays
It is one of the national holidays in Japan. This holiday was established as a national holiday by the Act on National Holidays that was promulgated and went into effect in 1948.
According to the Act, the purpose of this holiday is 'to admire nature and care for living things.'
By 1947, it was the holiday called "shunkikoreisai" (imperial ceremony of ancestor worship formerly held on the vernal equinox).

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

Date
The Vernal Spring Equinox Day falls around March 20 or 21.
Under the Act on National Holidays, it is set as 'the spring equinox.'
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 Vernal Equinox Day two years and beyond have not been fixed; however, days other than vernal equinox day obtained by an astronomical calculation has never been set as the Vernal Equinox Day so far. In addition, based on the astronomical calculation, the Vernal Equinox Day falls on March 20 in leap years and their following years and March 21 in other years until 2025.

[Original Japanese]