Most idiom and vocabulary apps dump dozens of words on you at once, and by next week you remember none of them. Korean four-character idioms, sajaseongeo, are especially bad for this: each one is a tiny packet of hanja, history, and meaning that deserves more than a flashcard swipe.
I built Idiom Day because I wanted to actually retain these idioms instead of cramming and forgetting them. The idea is simple: everyone in the world gets the exact same puzzle on the exact same day. You fill in one missing character, and whether you get it right or wrong, a learning card opens with the idiom’s meaning, the reading of each hanja character, its origin, and an example sentence.
There’s no feed to scroll and no deck to grind through. Just one idiom, once a day, every day, checked against the Standard Korean Language Dictionary so you’re not learning something half-remembered from a textbook.
Features
- One puzzle a day: a new idiom unlocks at midnight Korea time, and everyone solves the same one.
- Fill in the blank, with a hint: type the missing character, reveal an initial-consonant hint if you’re stuck, and you get three tries.
- A learning card every time: right or wrong, you get the meaning, hanja readings with English glosses, the idiom’s origin, and an example sentence with translation and romanized reading.
- Spaced review: idioms you’ve seen resurface after 1, 3, and 7 days, and you can replay any past puzzle from your archive.
- Streaks, stats, and spoiler-free sharing: track your current and best streak, accuracy, and a 12-week activity grid, then share the blanked puzzle with friends without giving away the answer.
I built this for my own use studying Korean, but it’s not limited to native speakers. In English, every card includes an English gloss for each hanja character, a translated example sentence, and the romanized reading, so you can type the answer in Hangul or just tap “I don’t know” to open the card and learn anyway. There’s about three years’ worth of puzzles already queued up, and no account is needed to start.
This is for anyone learning Korean, studying for a Korean proficiency exam, or just part of the Korean diaspora who grew up hearing these idioms but never learned the hanja behind them. It’s also for native speakers who want a one-minute daily habit instead of another app demanding their attention all day. If you’ve ever wanted to actually remember sajaseongeo instead of looking them up again every time, this is built for exactly that.
Idiom Day is live on Google Play now. It takes less than a minute a day, there’s nothing to sign up for, and the first puzzle is waiting whenever you open it.
