Evil Sudoku
Evil Sudoku: the hardest grids we have, from our Fiendish band. They open with as few as 24 numbers, and somewhere in the middle you will likely need an X-Wing or an XY-Wing to break through. Evil does not mean unfair: every grid is proved to have one solution that logic alone can reach, with no guessing.
- Tap a square, then tap a number to place it. Tap the same number again to take it back.
- Every row, every column and every 3x3 box holds the digits 1 to 9 exactly once.
- Switch on Notes to pencil in the candidates for a square. On the harder levels you will need them.
- Finished? Tap Play again for a fresh grid at the same difficulty.
🎯 Objective
Fill all 81 squares so the digits 1 to 9 appear exactly once in every row, every column and every 3x3 box. Every grid has one solution that logic alone can reach.
📊 How you score
Practice grids score points the same way the daily does, higher for harder grids and lower for time, hints and slips, so you can see how a solve went. They are not saved to the leaderboard or your solve streak: only the daily grid counts for those, and you can play as many practice grids as you like.
💡 Tips
- Scan for the digit that is already placed most often. The more copies on the board, the fewer squares are left for the next one.
- Work a box, a row and a column that all cross the same empty square. A digit ruled out by any one of them is ruled out for good.
- From Thursday on, pencil marks stop being optional. A square with only two candidates is the thread to pull.
- Two squares in a unit holding the same two candidates lock those digits away from every other square in that unit.
- Stuck? Tap Hint below the board. Three hints per grid, and each one names the rule that proves the move, then shows you the square and its digit, so you learn the pattern rather than just the answer.
Guides3
More ways to play Sudoku
Daily Sudoku
One grid a day, gentle on Monday and fiendish by Sunday. Same puzzle for everyone.
Easy Sudoku
Gentle grids, solved with singles alone.
Medium Sudoku
Fewer clues, and your first real technique.
Hard Sudoku
Long, tough grids. Pencil marks required.
Expert Sudoku
Pairs territory: for seasoned solvers.
Today’s best
Full board →How tough was Sudoku?
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