One house, in Seoul, that opens on its own schedule and not on mine. I have not yet been.
I have not been to Korea. It is the only country in this plate of which that is true, and I would rather say so at the top than let a confident paragraph imply otherwise.
The single entry here opens rarely and briefly, which is precisely why it is kept. A directory that only lists what is open on a Tuesday is a timetable, not a directory; the houses that show themselves twice a year are the ones worth arranging a life around.
So the plan is May, and the plan is to be told the dates by someone who lives there rather than to guess them from abroad. When I have stood in the room the mark will be filled in, and not one day before.