Medium German Whispers Sudoku
3
1
4
5
2
3
8
7
7
2
4
4
7
1
8
1
2
8
8
4
7
1
3
9
2
1
5
7
7
9
8
2
How to play German Whispers
Standard Sudoku rules apply. Any two adjacent cells along a green line must differ by at least 5. This forces alternation between large (6–9) and small (1–4) values.
About German Whispers
Difficulty
★★★★☆
4/5
Constraint Type
Line Constraints
Typical Givens
18–26
Avg. Solve (Medium)
22 min
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.
Solving Techniques
| Technique | Description | 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 Time by Difficulty
Easy
10 min
Medium
22 min
Hard
44 min
Expert
74 min