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Sudoku Atelier

Sudoku techniques

Eight techniques, in the order you need them. Each page explains the pattern, why it is valid, and how much it adds to a puzzle's rating.

Naked Single

A cell with one candidate left.

Hidden Single

A digit with only one home in a unit.

Locked Candidates

Pointing and claiming.

Naked Pairs

Two cells, two digits.

Hidden Pairs

Two digits, two cells.

X-Wing

A rectangle that eliminates candidates.

XY-Wing

A pivot and two pincers.

Swordfish

A three-line fish.

Suggested order

  1. Naked single / hidden single — the two you will use in every puzzle.
  2. Locked candidates — the first elimination technique; start using notes here.
  3. Naked and hidden pairs — then triples; same idea, bigger sets.
  4. X-Wing and swordfish — the fish family, for hard puzzles.
  5. XY-Wing — the gateway to expert puzzles.