How to Play Anti-Consecutive Sudoku
Orthogonally adjacent cells may not contain consecutive digits
The Rules
Standard Sudoku rules apply: fill every row, column, and 3×3 box with the digits 1–9, each appearing exactly once.
Anti-Consecutive Sudoku (a stricter form of Non-Consecutive Sudoku) imposes the rule that no two orthogonally adjacent cells may contain consecutive integers. This variant often requires fewer given digits because the constraint alone eliminates so many candidate pairs. It is sometimes combined with Anti-King or Anti-Knight to create extremely constrained puzzles.
At a Glance
How to Solve Anti-Consecutive Sudoku
Common Questions
What is Anti-Consecutive Sudoku? ▾
Anti-Consecutive Sudoku is a variant where no two orthogonally adjacent cells (horizontally or vertically neighbouring) may contain consecutive digits. The rule applies everywhere on the grid without any markers. Standard Sudoku rules also apply throughout.
How is Anti-Consecutive different from Non-Consecutive Sudoku? ▾
Anti-Consecutive and Non-Consecutive Sudoku are the same constraint — the name is used interchangeably by different puzzle communities. Both mean: no two horizontally or vertically neighbouring cells may hold digits that differ by exactly 1.
Which digit placements trigger the most eliminations? ▾
Digits in the middle of the range (4, 5, 6) eliminate two consecutive neighbours simultaneously. Placing a 5 removes both 4 and 6 from all four orthogonal neighbours, and placing those 4s and 6s in turn removes 3 and 7 from their neighbours — creating a cascade effect. Starting with central digits often unlocks large portions of the grid.
Is Anti-Consecutive Sudoku accessible for beginners? ▾
The rule is simple and the early eliminations are satisfying and obvious. Easy puzzles are well-suited for Sudoku players who want a step up from classic without learning arithmetic (like Killer or Arrow). The non-consecutive constraint is entirely logic-based.
What is the best approach to Anti-Consecutive Sudoku? ▾
Treat the anti-consecutive constraint as an additional elimination layer. After every digit placement, immediately update all four orthogonal neighbours to remove ±1 from their candidate lists. The more given digits you have to start with, the more these cascade eliminations interact.
How long does Anti-Consecutive Sudoku take to solve? ▾
Easy puzzles take 5–15 minutes. Medium puzzles run 15–30 minutes. Hard puzzles average 30–55 minutes and expert puzzles can take 60–90 minutes. Expert puzzles with very few given digits rely entirely on the anti-consecutive constraint for deductions.