How the date is worked out
The Korean calendar begins each month at the new moon, as seen in Korea’s time zone, so the 15th day comes at or near the full moon. Chuseok is the eighth month’s, at harvest time. The countdown runs to Chuseok itself; the three days off are the day before, the day and the day after.
How it’s celebrated
Families travel to their hometowns, hold memorial rites for their ancestors, visit and tidy their graves, and make songpyeon, half-moon rice cakes steamed on pine needles.