Best SudokuAnti-Knight
Anti-Knight Sudoku adds a chess rule to classic Sudoku: two cells a knight’s move apart can’t hold the same digit. A knight moves two cells in one direction and one cell sideways, so each digit you place knocks out up to eight more cells.
The rules
- Fill the grid so every row, column and 3×3 box holds 1 to 9.
- Two cells a knight’s move apart (like a chess knight) can’t hold the same number.
An example puzzle
An Easy Anti-Knight puzzle with 15 starting digits. It has one solution.
Solving tips
- Every placed digit removes itself from all cells a knight’s move away. Mark those cells in your notes straight away.
- Cells near the centre have eight knight-move partners, so they lose candidates fastest. Edge and corner cells have fewer.
- Look for a digit that appears often on the grid. Its knight-move shadows together with its row, column and box often leave one place.
- The rule stacks with normal Sudoku, so hidden singles now count knight’s moves too.
What changes from classic Sudoku
Puzzles usually start with fewer digits than classic Sudoku, because the extra rule does a lot of the work. The techniques stay the same, but you’ll find far more singles.
More ways to play
Print Anti-Knight puzzles · All variants · Sudoku techniques