Normal sudoku rules apply. Adjacent digits along the thin German Whispers line differ by at least 5. Adjacent digits along the thick Factor Line are factors or multiples of each other (including a factor of 1).
Solution code: Row 1
on 23. September 2025, 15:15 by Franjo
Absolutely nice puzzle! Thank you very much for creating and sharing.
on 23. September 2025, 13:56 by SquareCat
Never done a factor line constraint before! Very fun, thank you!