A balance of relaxation and challenge, with sensible use of Notes in some areas.
9×9 Sudoku board. Use the arrow keys to move between cells; Home and End go to the start or end of a row; Ctrl or Command + Home/End goes to the first/last cell on the board. Keys 1–9 enter a digit in the current mode; Shift + 1–9 adds a quick Note without turning Notes on; 0, Delete, or the numpad decimal key clears a cell; N toggles Notes, A toggles Auto Candidates, and Space pauses the game.
Levels 1–2 only guide you and do not use a hint; level 3 applies the solving step and uses 1 hint.
Select an empty cell to see valid candidates.
Auto candidates and Notes mode are remembered separately for Classic and Killer. Pause state and game progress are not synced as preferences.
At Medium, simple moves still appear but not continuously. Pencil marks become useful for tracking 2–3 candidates and spotting hidden singles.
Difficulty is not assigned from clue count alone. The site grader follows human techniques first, records the hardest technique reached, and uses residual search only when implemented logical techniques stall.
Techniques found: Hidden Single · Naked Single
This is one representative verified puzzle from the current verified quality pool. Difficulty remains an estimate because player experience changes how hard the same board feels.
Medium still has basic moves, but they do not appear continuously. You will start needing Pencil marks in stuck regions, hidden singles, and block-row or block-column intersections.
This is the best practice level once you understand the rules but want to improve candidate reading. Prefer selective notes, update them after every new digit, and avoid turning the whole board into a hard-to-read matrix of annotations.
Medium puzzles have fewer immediate singles. You will more often need pencil marks, hidden singles and block-line interactions before the next forced move appears.
No. A well-formed Medium Sudoku can be solved logically. If a cell has two possibilities, switch to another row, column or box and look for a forced elimination instead of guessing.
Try Hard Sudoku when candidate notes feel natural and you can solve Medium puzzles without leaving stale candidates behind. Hard puzzles make pairs and locked candidates more important.
The game board supports Notes, Undo, Pause, Hints, and saved progress. You can sign in later if you want to sync your achievements.
