Anti-King Sudoku
No two cells a king's move apart may contain the same digit
Anti-King Sudoku is fully playable. Choose a difficulty and start solving.
Borrowed from chess: a digit may never sit diagonally adjacent to a copy of itself, so every placement clears all eight surrounding cells. Corners and edges, with fewer neighbours, are the natural starting points. Quick to learn, and the diagonal pressure keeps mid-game deductions flowing.
For the complete rules, worked examples and solving techniques, read the full How to Play Anti-King Sudoku guide.
Like all Sudoku variants, Anti-King 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 |