Sudoku Evil - Play Free Expert Puzzles

Play evil Sudoku on LiveSudoku when hard puzzles no longer feel hard enough. Evil boards are expert-level 9x9 puzzles that reward careful pencil marks, patient scanning, and advanced logic. You will never need to guess - every evil puzzle is solvable by pure logic - but you will often need patterns that look across several rows, columns, or boxes at once. The smart Hint system can guide you through the next advanced step directly on the puzzle, with a full explanation instead of a blind reveal. Print an evil or hard sudoku PDF for offline solving.

Start with a clean candidate grid

Evil Sudoku depends on accurate candidates. Fill pencil marks, clear the singles first, and keep candidates updated after every placement. A single old candidate can hide the pattern you need.

Look for X-Wing

An X-Wing happens when the same digit is restricted to the same two columns in two different rows, or the same two rows in two different columns. That pattern lets you remove the digit from other cells in those lines.

Use Swordfish when X-Wing is not enough

Swordfish extends the same idea across three rows and three columns. It is harder to spot than X-Wing, but it can unlock expert puzzles when simpler eliminations stop working.

Try XY-Wing for advanced eliminations

XY-Wing, also called Y-Wing, uses three related two-candidate cells. When the pattern lines up, it lets you remove a candidate from cells that see both wings.

Evil Sudoku is the expert step above Hard. Hard puzzles usually focus on locked candidates, naked pairs, locked pairs, and hidden pairs. Evil puzzles ask you to find patterns that stretch across multiple rows or columns, including X-Wing, Swordfish, and XY-Wing.

If this level feels too intense today, use Hard Sudoku as training. If you are still building candidate habits, start with Medium Sudoku.

Work slowly and update candidates

Evil boards punish messy notes. After every placement or elimination, update the row, column, and box before searching for the next pattern.

Search for patterns by digit

Choose one digit and inspect where it can still appear across rows and columns. This makes X-Wing and Swordfish easier to see than scanning the whole grid at once.

Drop back to Hard when you want training

If Evil feels too slow, play a few Hard Sudoku boards and focus on clean candidate eliminations. That habit carries directly into advanced patterns.

LiveSudoku was created in 2006 by Mr. Izenberg and has offered free online Sudoku puzzles for nearly two decades. The goal is simple: clean Sudoku boards, helpful tools, no downloads, and puzzles for every level from beginner to expert.