Anti-Knight Sudoku
No two cells a knight's move apart may contain the same digit
Anti-Knight Sudoku is fully playable. Choose a difficulty and start solving.
Anti-Knight Sudoku extends Sudoku with a chess rule: any two cells reachable from each other by a chess knight's move (2+1 squares in an L-shape) cannot share the same digit. Each cell has up to 8 potential knight-move neighbours. This creates a rich constraint network that is separate from and extends beyond the standard row/column/box rules.
Like all Sudoku variants, Anti-Knight Sudoku builds on the classic 9×9 foundation. Every row, column, and 3×3 box must contain each digit from 1 to 9 exactly once. The variant constraint is added on top of these standard rules, never replacing them.
If you're new to Sudoku, start by learning the basic rules and techniques before attempting variants.
Techniques Useful for This Variant
| Technique | How it applies |
|---|---|
| Pencil Marks / Notes | Essential for tracking candidates alongside the variant constraint |
| Obvious Singles | Cells narrowed to one candidate by the combined constraints |
| Hidden Singles | Digits with only one valid cell in a unit after variant elimination |
| Pairs and Triples | Locked candidates exposed by the additional constraint |