It is a Buddhist ceremony which has been conducted in Japan from ancient times on every spring and autumnal equinox. Being rare objects from the Fuji area, it is fine to present anything at all. We can see from this that this ceremony was being conducted at Taisekiji in those days. Since Nikko Shonin conducted it, we can also naturally conclude that Nichiren Daishonin conducted it as well. As you know, on the days of the spring and autumnal equinox, day and night are the same length.
Day is bright, night is dark.
In terms of phenomena, this lightness and darkness are of equal duration. According to Buddhism, this shows that all things are equal with no distinctions. However, they offer you no guarantees about it. This is truly irresponsible. The Lotus Sutra does not.