Medium Anti-Knight Sudoku
5
4
9
3
5
2
8
9
5
3
3
6
9
8
3
5
7
2
4
5
7
7
1
2
2
6
5
3
4
4
2
6
Mistakes
0/3
Score
-
Time
00:00
Progress0%
♞ Knight's move constraint active
Medium · Anti-Knight
All Anti-Knight →
How to play Anti-Knight Sudoku
Standard Sudoku rules apply. Additional rule: no two cells reachable by a chess knight's move (2+1 squares in an L-shape) may contain the same digit. The constraint is invisible - No markers on the board - So keep it in mind as you solve.
About Anti-Knight Sudoku
Difficulty
★★★☆☆
3/5
Constraint Type
Anti-Constraints
Typical Givens
20–26
Avg. Solve (Medium)
12 min
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.
Solving Techniques
| Technique | Description | Level |
|---|---|---|
| Knight-Zone Mapping | For each cell, mark all potential knight-move destinations (up to 8 cells). None may share the same digit as the source cell. | Beginner |
| Corner and Edge Advantage | Corner cells have only 2 knight-move neighbours; edge cells have at most 4. These restricted zones are easiest to resolve first. | Beginner |
| Knight Chains | Placing a digit can eliminate it from a chain of knight-move positions that span diagonally across the grid. | Intermediate |
| Graph Coloring | Model the knight-move network as a graph and two-color it to find cells that cannot share a digit. | Advanced |
Average Solve Time by Difficulty
Easy
5 min
Medium
12 min
Hard
24 min
Expert
45 min