Sunday March 20 is the spring equinox, or Chunbun (춘분, 春分), marking the half-way point between the winter and summer solstices. Chunbun literally means "spring point of division," and marks the day when the lengths of daytime and nighttime are equal. This day also marks the beginning of the fourth of 24 solar terms that span the year.
As the lengths of the day and the night are equal, traditionally people believed that on this day there were exactly equal amounts of positive yang energy to the east (양, 陽) and negative yin energy to the west (음, 陰).

On Chunbun, the spring equinox, farmers till their fields and repair any damaged walls.
During both Goryeo (918-1392) and Joseon (1392-1910), the royal household would hold a special worship ceremony on the spring equinox praying to the God of the North, or Hyeonmyeongssi (현명씨, 玄冥氏), who represented the winter.
Around Gyeongju in the southeast, on the spring equinox people would visit the tombs of the three ancient kings Park (박, 朴), Seok (석, 昔) and Kim (김, 金). They founded the Silla Kingdom (57 B.C.-A.D. 935) and fathered the three main family clans of Gyeongju.
Finally, the weather on the spring equinox was particularly important. The day was normally neither hot nor cold, so the farmers could prepare their fields for the year's harvest.
By Gregory C. Eaves
Korea.net Staff Writer
Photos: Encyclopedia of Korean Folk Culture
gceaves@korea.kr