On 21 March this year, give the Spring Equinox. On this day the number of hours of light and darkness are equal. So over the humanity of history thousands of years this day has had great significance. (The same happens in the Autumn Equinox, on 23 September)
In Japan this day has a profound religious significance. It is a Buddhist belief that our world is separated from Nirvana by a river and the souls of the dead have to pass it to reach Nirvana. When they reached the other side said that they reached the Higan, literally, “the other side”. But this task is not easy and many are lost. Then the Equinox Buddha comes and helps those who are lost.
So during the 7 days of Haru no Higan, families think of their deceased relatives. Especially on the day of the equinox, the Shunbun no hi, the Japanese visit the memorial tombs of their relatives, clean them, put them new flowers, burn incense and arrange that sutras are read by their deceased loved ones.
Today only some Japanese continue to celebrate this day in this way. Most of the Japanese only celebrate this day by its secular side. As it is a national holiday, the Japanese have a day off on this day. Most of the Japanese enjoy this day to pass it in the family. This might include having to go to your city or hometown.
This day is also important for farmers because officially marks the end of winter. Some pray and make offerings for a prosperous and good harvest.