Camera Sudoku guides

Practical how-tos for scanning paper Sudoku puzzles and learning the strategies that solve them.

How to scan a Sudoku with your phone camera

Turn a newspaper or puzzle-book Sudoku into a digital puzzle with your Android camera. Tips for framing, lighting, handwriting and tricky photos.

Sudoku solving strategies, from singles to chains

A plain-language tour of the Sudoku techniques Camera Sudoku's Smart Hints teach: singles, pairs, pointing, X-Wing, Swordfish, wings, Unique Rectangles and chains.

A Sudoku solver that works offline

Solve and learn Sudoku without an internet connection. What works offline in Camera Sudoku, and what needs a connection.

Naked Pair in Sudoku: how to spot it and use it

What a Naked Pair is, why it works and how to find one, with a real example from a scanned newspaper Sudoku. Plus Naked Triples, Quads and Hidden Pairs.

X-Wing in Sudoku: the strategy explained with an example

How the X-Wing Sudoku technique works, how to find one step by step, and a real example from Camera Sudoku's Smart Hint. Plus Finned X-Wing, Swordfish and Jellyfish.