The "No-9 Line"
(Published on 7. February 2026, 08:23 by Timpanist)
- Normal sudoku rules apply.
- Loop: Draw a single closed loop that moves orthogonally and does not branch or intersect itself. The loop must visit every cell except for the nine cells containing a 9.
- Box-Local Sums: The 3x3 box borders divide the loop into segments. Within a box, every segment must have the same sum. (This sum may vary from box to box). Every box must have at least two segments.
- No two adjacent cells directly connected by the loop may sum to 9.
Solution code: Row 4 (digits left to right)
Comments
on 10. February 2026, 17:51 by mscha
What a beautiful puzzle with a great new original ruleset! Hard but very satisfying!
on 10. February 2026, 11:22 by Christounet
Great! Very clever setup, and impressive that you could find a grid that solves at all. Thanks :)
on 10. February 2026, 03:55 by darkgently
Clever puzzle! Loved the variety of interactions between the region sums, sudoku, and loop topology.
on 10. February 2026, 03:26 by Timpanist
A huge thank you for all the support! Your comments mean so much to me!
on 9. February 2026, 22:47 by QuiltyAsCharged
Terrific and very original!
on 9. February 2026, 21:00 by oskode
Fantastic idea and execution, thank you for sharing!
on 8. February 2026, 12:56 by Snookerfan
Fabulous! Seems impossible until you realise what is actually going on. Thanks
on 7. February 2026, 22:16 by cyddrdrd
Nice and smooth! The constraint is surprisingly much stronger than its appearance.
on 7. February 2026, 19:29 by Timpanist
Thank you! I appreciate it
on 7. February 2026, 17:02 by MonsieurTRISTE
Amazing! Would love to see it getting a 100% rating.
on 7. February 2026, 11:27 by Mr. Happy
This was great! Lovely puzzle with a very cool constraint. I like how the constraints give you some high level logical deductions but then putting the pieces together still took some interesting thought. Good layers.
