The case notes
Test a candidate through meeting Whisper lines
Two German Whisper lines meet here. We know a one at the end of the first, but the far end of the second is empty. Watch a worked example, then try the idea in a puzzle.
Put it into practice
Two lines, one meeting point
Two German Whisper lines meet here. We know a one at the end of the first, but the far end of the second is empty.
Shared cell must be high
One is low. A five-apart Whisper must jump to a high digit, so the shared cell has to be high.
Suppose r4c8 = 2
Try two at the far end of the other line. This is a candidate under the ordinary row, column and box rules.
Shared cell: low and high?
Two is low, so the next cell along must be high. The following cell, our shared cell, must be low again. But the first line needs it high.
r4c8 cannot be 2
One cell cannot be low and high. Our trial two was wrong, so remove two from the far end.
Read the transcript
Two German Whisper lines meet here. We know a one at the end of the first, but the far end of the second is empty. One is low. A five-apart Whisper must jump to a high digit, so the shared cell has to be high. Try two at the far end of the other line. This is a candidate under the ordinary row, column and box rules. Two is low, so the next cell along must be high. The following cell, our shared cell, must be low again. But the first line needs it high. One cell cannot be low and high. Our trial two was wrong, so remove two from the far end.
Keep following the clues
- German whisper Sudoku: How German Whisper lines work →
- Kropki Sudoku: Carry a Whisper’s side through a black dot →
- Kropki Sudoku: Let a Whisper choose between dot-chain options →
- German whisper Sudoku: Count low and high digits around a Whisper line →
- German whisper Sudoku: Join two Whisper colour patterns where they meet →
