Helpful SudokuThe story behind the game
About Helpful Sudoku
A Sudoku game for people who enjoy the puzzle, and for people learning how to solve it.
Who runs Helpful Sudoku?
Helpful Sudoku is owned and maintained by Chris McGowan.
For questions, feedback or help with the game, visit our Contact us page.
How it started
Helpful Sudoku grew out of Chris McGowan’s work on a Sudoku solver and puzzle generator. Building those tools led to a question: how could a game show the reasoning behind a move while still letting the player do the thinking?
The project has developed through collaboration and feedback, with the solver, puzzle collection and playing experience evolving together.
Choose your own level of help
Some days you may want a quiet challenge with no assistance. Other days you may want candidate lists, a hint or an explanation of a hidden single. Helpful Sudoku lets you choose those aids separately from the puzzle’s difficulty.
Classic Sudoku uses rows, columns and 3 × 3 boxes. X Sudoku adds both long diagonals. The game supports both, with notes, undo, rollback and a solver you can watch when you want to see how it approaches a puzzle.
Where the puzzles come from
The puzzle collection is produced with our generator and checked by a solver for a unique solution. Difficulty labels are estimates based on solving effort. We are refining those estimates to better reflect the deductions a person needs to make.
A computer’s search count does not always match a player’s experience. If a puzzle seems much easier or harder than its label, that is useful feedback.
Made for learning and playing
The player’s guide explains the rules and controls. Our solving guide gives examples of candidates, naked singles and hidden singles that you can apply to your next puzzle.
You can play in a browser on a computer or phone without creating an account. Assistance is optional, and you can turn it down as you become more confident.
Play Sudoku →