March 20 in 2021
Shunbun (春分) is the 4th of 24 solar terms (節氣) in the traditional East Asian calendars.
It is the Vernal Equinox Day.
In Japan, this day is a holiday for “the day to praise nature and love creatureds”.
It is also the middle day of equinoctial week (higan / 彼岸), in which people visit graves of ancestors and visit temples.