Upvote:1
At Seoul (ICN) you can transit for up to 24 hours, because the transit area remains open overnight. Other airports close their transit areas at night, so you can only transit within the same day there.
Upvote:5
The bullet point excepting ICN applies to the second TWOV facility, the one that begins "Visa required, except for passengers with a confirmed onward ticket for a flight to a third country on the same calendar day." This TWOV facility applies everywhere except ICN, while the first TWOV facility applies at ICN.