Claire's Sudoku Downloads & RevenueClaire's Sudoku: Daily Puzzle · App Store

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 n