Hard Sudoku X

Hard Sudoku X — around 28 givens. By this tier the puzzle assumes you'll scan the diagonals every pass. Place a digit on a diagonal cell, and you've eliminated it from eight other cells at once.

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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