For experienced players who need to combine several elimination techniques before a clear move appears.
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.
Expert Sudoku often does not open with an obvious single. Complete your notes in the relevant regions, then look for triples, locked candidates, and row/column patterns before moving to more complex techniques.
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: Naked Single · Hidden Single · Locked Candidates · Naked Pair
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.
Expert Sudoku is for players already comfortable with pairs, triples, and locked candidates. A solving step often connects several regions of the board instead of focusing on only one row or block.
Complete Notes in the regions involved in the same pattern, then check triples, block-row/column interactions, and patterns such as basic X-Wing. Eliminate a candidate only after all four points of the pattern are clearly confirmed.
You should be comfortable with full candidate tracking, pairs, triples and locked candidates. Expert puzzles may also require recognizing an X-Wing or another multi-region elimination pattern.
Yes. The goal is logical elimination. If a chain becomes too long to verify, recheck basic candidates, pairs and block-line interactions before making an assumption.
Move to Master when advanced candidate patterns feel repeatable rather than lucky, and you can complete Expert boards while explaining why each elimination is valid.
There is no single correct time for solving a Sudoku puzzle. A beginner may need 30 minutes for an easy grid, while an experienced…
Read articleThe game board supports Notes, Undo, Pause, Hints, and saved progress. You can sign in later if you want to sync your achievements.
