German Whispers

Rules

On a German whisper line, two digits sitting next to each other must differ by at least five. A 2 next to a 3 is illegal; a 2 next to a 7 or an 8 is fine. Long whispers become corridors of extremes.

• Adjacent digits on a green line differ by 5 or more.
• The constraint applies along the line only, not to the rest of the grid.
• A digit in the middle of a whisper is squeezed: it must be far from both neighbours.
• Low and high digits alternate along the line, but never by exactly four.

Good to know

Ordinary sudoku rules still apply underneath the variant: every row, column and 3×3 box holds 1–9 exactly once. The extra rule sits on top and is usually what breaks the puzzle open.

More sudoku

All sudoku variants ↗

Or read how to play Sudoku ↗.