What is a Naked Single in Sudoku?
The most fundamental strategy in sudoku — and the one every beginner needs to understand first. Once you see it, you'll never look at a board the same way.
Read the guide →7 Sudoku Tips That Will Make You Actually Good
Concrete, specific tips that immediately change how you solve puzzles. Not the vague stuff you've read before.
Brain ScienceWhy Playing a Daily Sudoku Puzzle Changes Your Brain
There's real neuroscience behind why a daily sudoku habit makes you sharper. Here's what the research actually says.
Strategy BasicsWhat is a Naked Single in Sudoku?
The most fundamental sudoku strategy — and the one every beginner needs to understand first.
Strategy BasicsWhat is a Hidden Single in Sudoku?
A hidden single is where a digit can only go in one cell in a row, column, or box — even if that cell has multiple candidates. The technique that unlocks Medium puzzles.
Intermediate StrategySudoku Naked Pair Explained (Step-by-Step)
When two cells in the same unit share only the same two candidates, those digits can be eliminated everywhere else in the unit. The key to Hard puzzles.
App ReviewsBest Sudoku App for Learning Strategy (2026)
We built Sudoku Coach, so we're biased — but here's our honest comparison of every major sudoku app and what each one is actually good for.
Ready to Practice What You've Learned?
Sudoku Coach explains every hint with the actual strategy name and reasoning. Free to download, no ads, ever.