German Whispers
Adjacent digits on the green line must differ by at least 5
Easy
German Whispers Easy
Medium
German Whispers Medium
Hard
German Whispers Hard
Expert
German Whispers Expert
What is German Whispers?
German Whispers (also known as Whisper Sudoku) draws green lines on the grid. Any two digits that are adjacent on the line must differ by at least 5. Because the minimum difference is 5 and digits range from 1–9, this creates a strong alternating high-low pattern: if one cell is low (1–4), the next must be high (6–9) and vice versa. The line constraint eliminates 5 as a valid digit in most positions.
At a Glance
| Constraint type | Line Constraints |
| Typical givens | 18–26 |
| Difficulty rating | ★★★★☆ 4/5 |
| Avg. solve time — Easy | 10 min |
| Avg. solve time — Medium | 22 min |
| Avg. solve time — Hard | 44 min |
| Avg. solve time — Expert | 74 min |
How to Solve German Whispers
| Technique | What it does | Level |
|---|---|---|
| High-Low Alternation | Adjacent cells on the line must differ by ≥ 5. This forces a strict alternating high-low pattern: low (1–4) alternates with high (6–9). | Beginner |
| Digit 5 Exclusion | 5 cannot appear on any German Whispers line — no digit within 1–9 differs from 5 by at least 5. Eliminate 5 from all line cells immediately. | Beginner |
| Low-Set {1,2,3,4} / High-Set {6,7,8,9} | Every whisper cell belongs to one of these two sets. Apply row/column/box constraints within each set to narrow candidates. | Intermediate |
| Endpoint Parity | The parity (high or low) of the line is not fixed — it's determined by surrounding constraints. Resolving one endpoint propagates the alternation inward. | Advanced |
Average Solve Times
Easy
10 min
Medium
22 min
Hard
44 min
Expert
74 min
Frequently Asked Questions
Why can't 5 appear on the line?
Any digit adjacent to 5 on the line must be ≤ 0 or ≥ 10 — both impossible within 1–9.
Must the pattern start from a specific end?
No — either end can be high or low. The parity is determined by the broader puzzle constraints.