Korean 100 Day Anniversary: Confession Day and Korea's Couple Math

September 17 is 고백데이 — Confession Day — a date built on simple arithmetic: confess now, and you have about a hundred days to be a couple by Christmas. It is not a public holiday, but it is a perfect window into something very real in Korean dating culture: couples count days, and they have vocabulary for every stage of it.

Here’s the language, from the almost-something stage all the way to the hundredth day.

Before anything is official: 썸

Korean has a dedicated word for the stage English has to describe in a whole sentence — that period where two people are clearly interested but nothing has been said.

썸 comes from English something, and the verb 썸타다 uses 타다, the verb for riding — you ride the something. It matters grammatically too: 썸 is a noun, so it behaves normally in sentences (썸이 있어요, 썸을 타요).

The 고백 is what ends the 썸 stage, in one direction or the other.

The confession itself, in order

Korean confessions follow a recognisable escalation, and skipping steps sounds strange rather than romantic.

The order is 좋아해요 first, then the direct question about dating, and 사랑해요 much later.

In Korean, 사랑해요 carries real weight — it is not a casual sign-off the way love you can be in English, and using it at the confession stage sounds like a leap.

The one-two of 좋아해요 plus 우리 사귈래요? is the standard package, and the answer that starts the clock is simply 네 (yes).

The tone of all of this lives in text messages as much as in person, and Korean chat has its own rules — our guide to Korean texting culture covers those.

Day one, and the counting that follows

The moment someone says yes, a calendar starts. This is the part that surprises most learners.

우리 오늘부터 1일 is one of the most quoted lines in Korean dramas for a reason: it converts a vague situation into a fixed date that both people will count from.

After that come 22일 (nicknamed 투투데이 from the doubled two), 100일, then 200일, 300일, and 1주년 for the first year.

The milestones are usually marked with a meal, a photo, and a small gift rather than anything elaborate.

Two language notes make the counting easier. First, all of these use Sino-Korean numbers, the same set you use for dates and money — worth reviewing on our Korean numbers page if the two number systems still trip you up.

Second, 100일 is read 백일 and pronounced with the liaison, bae-gil, not one syllable at a time.

Why a day like this exists at all

Korea has a whole calendar of couple-adjacent days on the fourteenth of each month, and 고백데이 sits alongside them as a commercial invention with a neat piece of logic attached — confess on September 17, and Christmas arrives with someone to spend it with. Nobody treats it as an obligation, and plenty of people ignore it completely.

What’s genuinely useful about it for a learner is the vocabulary it drags into view: 썸, 고백, 사귀다, 1일, 기념일. These are words you’ll meet in almost any Korean drama, song lyric, or variety show within a few episodes.

Pair them with the feelings and emotions vocabulary and a surprising amount of romantic dialogue starts decoding itself.