The next ones
- September 29Tuesdaylunar 8/19
- September 30Wednesdaylunar 8/20
- October 9Fridaylunar 8/29
- October 10Saturdaylunar 8/30
- October 19Mondaylunar 9/9
- October 20Tuesdaylunar 9/10
What son-eomneun-nal means
Son (損) is an old word for a wandering spirit that was thought to interfere with whatever people were doing. It was not believed to be everywhere at once: it moved around the compass on a schedule tied to the lunar date. On days whose lunar date ends in 1 or 2 it sat in the east, on 3 or 4 in the west, on 5 or 6 in the south, on 7 or 8 in the north — and on days ending in 9 or 0 it was nowhere at all.
Those last days are son-eomneun-nal, literally “days without son.” Lunar dates 9, 10, 19, 20, 29 and 30, which works out to five or six days in every lunar month. They are the days chosen for moving house, opening a shop, and starting anything that would be a nuisance to redo.
Why the dates move every year
The rule is fixed but it runs on the lunar calendar, and lunar dates drift against the solar one. A lunar month is about twenty-nine and a half days, so the gap opens by roughly eleven days a year until a leap month resets it. That is why the same custom gives completely different solar dates each year, and why a list printed last year is no use now.
The dates above are worked out from the lunar conversion each time, not read off a stored table, so they hold for whatever year you are looking at this in.
If you are moving in Korea
This is worth knowing even if you put no stock in the custom, because it moves prices. Moving companies and ladder-truck operators are busiest on these days and quote accordingly; a weekday that is not son-eomneun-nal can cost noticeably less for the same job. If your landlord or your in-laws care about the date, you will hear about it — and if nobody does, booking around these days is the cheaper choice.
The same custom covers opening a business, signing a lease, and moving an ancestral shrine. It does not cover weddings; those are chosen by a different method that works from both people's birth dates.
The full calendar
Month-by-month listings are in Korean, but they are mostly dates — usable without much reading.