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A little time for your Sudoku.

My progress
Errors 0
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Keyboard shortcuts

Enter a number
1–9
Move selection
↑ ↓ ← →
Undo
⌘ / Ctrl Z
Erase
Backspace / Delete
Notes
N
Hint
H
Pause / resume
P

You can also drag a number to any blank cell.

Master difficulty

Settings

Colour theme

System follows your device’s light or dark appearance.

Remaining Candidates

Show how many of each number are left to place. Hide its button when all nine are on the board.

Fast Notes

Add Fast Notes to the Notes menu. Choose it while playing, or hold the pencil, to add the same note to several cells.

Note Conflict Check

Reject notes blocked by a number in the same row, column, or box, and highlight the numbers blocking them.

Evil Sudoku

Evil Sudoku is designed to frustrate and delight in equal measure. These diabolically crafted puzzles feature minimal clues and require advanced or even expert-level solving techniques. If you have mastered hard and expert levels and crave something even more demanding, evil Sudoku is your ultimate test.

About Evil Sudoku

Evil Sudoku puzzles are curated for maximum difficulty. They typically require multiple advanced techniques in sequence, including chained eliminations, advanced coloring, and sometimes even uniqueness-based arguments. There are no shortcuts and no easy cells. Every number you place must be earned through rigorous logical deduction.

What is evil Sudoku?

Evil Sudoku is the highest difficulty tier offered by many puzzle sites. It refers to puzzles that cannot be solved with basic or even most intermediate techniques. You will need a deep repertoire of advanced strategies and the patience to apply them systematically. Evil puzzles are for experienced solvers who want the toughest possible challenge.

How do I solve evil Sudoku puzzles?

Start by completing all pencil marks meticulously. Then cycle through advanced techniques: look for X-Wings, Swordfish, XY-Wings, and remote pairs. If those do not work, try coloring (assigning tentative values and following their logical consequences). Evil puzzles often require chaining multiple techniques together.

Is evil harder than expert Sudoku?

Evil is typically the hardest difficulty available. While expert puzzles may require one or two advanced techniques, evil puzzles often require several advanced techniques applied in sequence. The solving path is longer and more convoluted, with fewer obvious next steps at any given point.