How to Play Non-Consecutive Sudoku
No two orthogonally adjacent cells may 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.
Non-Consecutive Sudoku imposes a global constraint: no two cells that share an edge (orthogonally adjacent) can contain consecutive digits. So if a cell contains 5, all its neighbours must avoid 4 and 6. This single rule dramatically limits candidate placements and can reduce a standard givens count while still producing a uniquely solvable puzzle.
For where this puzzle came from, how it compares with related variants and a strategy summary, see our Non-Consecutive Sudoku variant overview.
At a Glance
How to Solve Non-Consecutive Sudoku
Common Questions
What is Non-Consecutive Sudoku? ▾
Non-Consecutive Sudoku is a variant where no two horizontally or vertically adjacent cells may contain consecutive digits. There are no markers on the grid — the non-consecutive rule applies globally to every pair of neighbours. Standard Sudoku rules also apply.
How does the global non-consecutive rule constrain the grid? ▾
Every pair of adjacent cells cannot differ by exactly 1. This means you cannot place a 4 next to a 3 or a 5. For every digit you place, you must eliminate that digit ±1 from all orthogonal neighbours. This propagates eliminations across the entire board immediately after every placement.
Which digits are most affected by the non-consecutive rule? ▾
Digits 1 and 9 can only be invalid next to 2 and 8 respectively — so they are least affected. Digit 5 cannot be adjacent to either 4 or 6, which is a moderate restriction. Digits 4, 5, and 6 are most affected because they are adjacent to two common digit pairs simultaneously.
Is Non-Consecutive Sudoku harder than regular Sudoku? ▾
Yes, typically. The global constraint eliminates many more candidates than standard rules alone. Easy puzzles are accessible and resolve quickly. Hard and expert puzzles compensate with fewer given digits, making the non-consecutive constraint the primary source of all deductions.
What is the best first strategy for Non-Consecutive Sudoku? ▾
After placing each digit, immediately mark all orthogonal neighbours as unable to hold ±1. Scan rows and columns for digits that can now only go in one cell due to these combined eliminations. Digit 5 is particularly useful as a placement anchor — wherever 5 is placed, both 4 and 6 are eliminated from all four neighbours.
How long does Non-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. Non-Consecutive Sudoku rewards players who apply the constraint globally and systematically after every move.