CHALLENGE
Sudoku School First Term
Term runs two weeks: take the placement test, learn Claire's techniques, and earn a dated belt certificate.
Claire's Sudoku: Daily Puzzle
13 lessons that end guessing
Only for iPhone
Free · Designed for iPhone. Not verified for macOS.
iPhone
You fill in the easy squares, hit a wall, and then put a number down just to see what happens. Claire teaches the thirteen moves that replace the guess.
Claire Kaplan teaches thirteen sudoku techniques, in the order that makes each next one make sense, beginning with the first empty square. Every lesson is played on a real board, and she explains the move in plain language while you make it yourself.
This is a complete sudoku app, and the school sits inside it. Claire teaches one technique at a time.
WHERE DO I START?
Take the placement test. It is five questions, one board each, with no timer and nothing to pass or fail. Claire asks you for the one square that is certain, or the one note that is impossible, and you tap it. You can also tell her you are not sure yet. She credits you with everything easier than the first question you miss, and starts teaching there. You can retake it whenever you like, on fresh boards.
THE THIRTEEN TECHNIQUES, IN ORDER
The White belt teaches the full house, the naked single, and the hidden single, which fill in what is already certain.
The Yellow belt teaches the pointing pair and box line reduction, so you can keep notes and lock digits down.
The Orange belt teaches the naked pair and the hidden pair, which are two squares that share a secret.
The Green belt teaches the naked triple and the hidden triple, which are three of a kind.
The Blue belt teaches the X-Wing, and it is your first fish.
The Purple belt teaches the Y-Wing, the XYZ-Wing, and the Swordfish, which are the wings and the bigger fish.
There are six belts and thirteen lessons in all.
The lessons run on 117 teaching boards, and each one was checked three ways before it shipped. Every board can be finished by the thirteen techniques with no guessing, its hardest required move is exactly the technique the lesson is teaching, and it has exactly one solution. Repeat a lesson and you get a different board.
ONE MINUTE A DAY
The Daily Drill is five questions, drawn from the techniques Claire has taught you. Anything you have stumbled on comes back about twice as often. You cannot fail it. Nothing runs out, and a wrong answer costs you nothing. A wrong tap shakes the board, says "Not that one," and leaves the question open, and you can skip one if you like. Answering quickly earns more points, and answering slowly still earns them, so your best score is a target you set yourself. There is no leaderboard.
BELTS AND CERTIFICATES
Finish every lesson in a belt and Claire awards it. The certificate is a card with the belt, the techniques it covers, the date, and Claire's name. You can share it as a line of plain text.
WHO TEACHES IT
Claire Kaplan teaches every lesson in the app. She stays on the board with you until you find the move yourself.
THE SUDOKU ITSELF
Puzzles are generated on your phone, so you cannot run out. You can play at five difficulties, from Easy through Medium, Hard, and Expert up to Master. The thirteen finish every Easy, Medium and nearly every Hard board. Most Expert boards fall to them, and Master often asks for more. There is one daily puzzle, the same for everyone, on the newspaper ramp from an easy Monday to a Master Saturday. You get pencil notes, unlimited undo, and one hint per puzzle, which fills in a single correct digit. A timer and a mistake tally are both there, and both stay off until you switch them on. You can set the board to light or dark, or to Night, which is a warm red screen for playing in bed.
The streak on your home screen counts any day you did something, whether that was a puzzle, a lesson, or a drill. It cannot be spent or frozen, and nothing scolds you for missing a day.
NO ADS
There are no ads anywhere in the app. Every lesson, every belt, every difficulty, and every daily puzzle is open to you. There is no account and no sign-in, and your progress is stored on your phone. The lessons, the drill, and the daily puzzle all work with no connection. One daily reminder is available in Settings, and it stays off until you turn it on.
Sudoku is a set of moves, and Claire will teach you all thirteen.
Events
Claire can now remind you in the morning, afternoon, or evening after you finish a daily puzzle. Today's edition and a practice board prepare before you tap, Notes stay available during play, and ready updates can be applied from a clear in-app prompt.
The developer, BUILT BY FOUNDRY, INC., indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- BUILT BY FOUNDRY, INC.
- Size
- 66.3 MB
- Category
- Puzzle
- Compatibility
Requires iOS 15.1 or later.
- iPhone
Requires iOS 15.1 or later. - iPod touch
Requires iOS 15.1 or later. - Mac
Requires macOS 12.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPhone
- Languages
- English and Japanese
- Age Rating
4+
- 4+
- Copyright
- © 2026 Built by Foundry, Inc.