So we have 春分=shun-bun, vernal equinox and 4th of spring 二十四節気 today. It is celebrated as one of national holidays in our country, with 秋分=shu-bun, autumnal equinox as well. Mei-Shun has wondered why only these 2 days among 24 are included. It might be partly because we have the most number (17) of such commemoration in the world.