Hard Killer Sudoku

Hard Killer Sudoku — around 12 givens. The cage constraint does most of the work. Two-cell cages summing to 3, 4, 16, or 17 have forced digit pairs; lean on those.

Hard puzzles introduce locked candidates, pointing pairs, and box-row interactions. Expect 15–25 minutes per puzzle if you're comfortable with those techniques — and steady pencil-mark discipline.

Available packs

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