Expert Sudoku Puzzles

A puzzle is rated Expert here when its hardest required technique is X-Wing or Swordfish — verified by a solver, not guessed from a star rating. 25,010 of the 65,284 puzzles in our library are rated Expert. How our difficulty ratings work.

Expert puzzles require the fish patterns — X-Wing and Swordfish — where a candidate locked into matching rows and columns eliminates it across the rest of the grid. These are the hardest puzzles in our library and assume every earlier technique is second nature.

Expert puzzles require a fish — an X-Wing or a Swordfish — and the jump they represent is not really one of difficulty but of scope. Every earlier technique reasons inside a single unit. A fish reasons about where a digit can live across several lines at once, which is a different kind of looking and does not become easier through practising subsets.

The condition to watch for is a digit reduced to very few possible cells per line. That is why the tier is unforgiving of skipped steps: the fish only becomes visible after the cheaper eliminations have done their work, so a solver who hunts for it too early will correctly conclude it is not there.

If the pattern itself is the obstacle rather than the search, the fish guides derive both from first principles, which is more durable than memorising the shape — the transposed version catches out anyone who learned it as a picture.

Play expert puzzles

  1. Expert puzzle #1 — 26 givens · needs Naked Single, Hidden Single, Naked Pair, Omission, Naked Triplet, X-Wing
  2. Expert puzzle #2 — 26 givens · needs Naked Single, Hidden Single, Omission, X-Wing, Swordfish
  3. Expert puzzle #3 — 24 givens · needs Naked Single, Hidden Single, Omission, Naked Triplet, Hidden Pair, X-Wing
  4. Expert puzzle #4 — 24 givens · needs Naked Single, Hidden Single, Naked Pair, X-Wing, Swordfish
  5. Expert puzzle #5 — 24 givens · needs Naked Single, Hidden Single, Naked Pair, Omission, Hidden Triplet, X-Wing
  6. Expert puzzle #6 — 23 givens · needs Naked Single, Hidden Single, Naked Pair, Omission, Naked Triplet, Hidden Pair, Swordfish
  7. Expert puzzle #7 — 23 givens · needs Naked Single, Hidden Single, Omission, Naked Triplet, Hidden Triplet, X-Wing
  8. Expert puzzle #8 — 27 givens · needs Naked Single, Hidden Single, Naked Pair, Naked Triplet, Swordfish
  9. Expert puzzle #9 — 25 givens · needs Naked Single, Hidden Single, Omission, X-Wing
  10. Expert puzzle #10 — 25 givens · needs Naked Single, Hidden Single, Omission, Naked Triplet, Hidden Triplet, Swordfish
  11. Expert puzzle #11 — 23 givens · needs Naked Single, Hidden Single, Omission, Naked Triplet, Hidden Pair, X-Wing
  12. Expert puzzle #12 — 23 givens · needs Naked Single, Hidden Single, Naked Pair, Omission, Naked Triplet, Swordfish
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Expert Sudoku FAQ

What makes a Sudoku puzzle expert?
On Precision Sudoku, difficulty is defined by the hardest technique a puzzle actually requires, verified by a solver — not by a vague star rating. A puzzle is rated Expert when the hardest move it needs is X-Wing or Swordfish.
How many expert Sudoku puzzles are there on Precision Sudoku?
25,010 of the 65,284 verified puzzles in the Precision Sudoku library are rated Expert, meaning their hardest required technique is X-Wing or Swordfish.
When in the solve should I start looking for an X-Wing?
Last. Exhaust singles, omissions and subsets first, because a fish needs a digit confined to very few cells per line and those cheaper techniques are what produce that condition. Searching earlier usually means searching a grid that does not contain the pattern yet.
Are Expert puzzles just Hard puzzles with more steps?
No, and that is the point of the tier. The difference is scope rather than length: every technique below this one reasons within a single row, column or box, while a fish reasons about a digit's possible positions across several lines simultaneously. More practice at subsets will not produce it.