Normal Sudoku rules: Every row, column and box must contain the digits 1-9
Arrow rules: Digits along an arrow sum to the number in their attached circle.
German Whispers: Neighbouring digits on a thick blue line have a difference of at least 5.
Sudoku X: Each long diagonal must contain all of the digits 1 through 9.
f-puzzles link: https://f-puzzles.com/?id=yjjy2c8l
CtC link: https://tinyurl.com/k8c2rzsm
Solution code: Row 2 and Row 8 (18 digits)
on 12. September 2021, 03:25 by apiyo
Upgraded difficulty
on 11. September 2021, 16:42 by antiknight
I think the difficulty for this one is 4 or slightly higher. Thanks for sharing this amazing puzzle.