Jörmungandr
(Published on 2. June 2022, 13:46 by Jay Dyer)
This is my second region sums deconstruction puzzle. The last one had quite a few short lines in it. This one has... well, you can see.
Rules
- Deconstruction: Contained within the grid are nine non-overlapping 3x3 square regions, which must be located. Each region contains the digits 1-9 once each such that no digit repeats in any row or column. Cells outside regions do not contain digits.
- Region sums: Along the line, each time the line passes through a region, the sum of the digits on that pass sum to the same value. If the line passes through a region multiple times, each pass is summed separately.
Solution code: Row 10 followed by column 9 (use X for empty cells)
Comments
on 21. July 2025, 17:42 by StephenR
Lovely puzzle, thanks. Cracked the squares in good time, but took me longer to resolve the sudoku in part due to brain switching off for a time.
on 20. November 2023, 02:51 by zzw
Tons of fun the whole way through! It was a bit easier and smoother than I expected from the comments. And of course, an incredible construction!
on 29. October 2023, 19:31 by Piatato
Very clever construction, and I must say that it's really about time that I finally got around to solving this great classic!
on 7. April 2023, 10:24 by Yann
The boss of lines !
What an incredible puzzle it was, I loved the disambiguation.
Thanks for sharing this impressive sudoku.
PS Do I have to ask you permission to set a puzzle inspired by this one ?
on 20. November 2022, 16:26 by meixia
I thought I had seen many puzzles which appear impossible, but this one tops the list! Very impressive.
on 21. October 2022, 16:21 by Vebby
Astonishing! Some big-brain construction to achieve this. Great logic throughout. Thanks Jay!
on 17. October 2022, 19:12 by twototenth
Madness. (Is that you for setting it, or me for solving it? Yes.)
on 25. June 2022, 02:20 by SHERAX
Started watching CTC-solve on YouTube. paused it Solved it and continued watching. Looked Simon had more trouble solving this one than i did. Very colorful result at the end. More colors is better……Lovely…The single line is GENIUS.
on 18. June 2022, 04:06 by OGRussHood
Another "mad as a box of frogs" puzzle.
on 17. June 2022, 01:10 by SimplePurpleFrog
Wow, hard, but I loved it from start to finish.
Great logic and very basic maths, just as I like it.
on 16. June 2022, 20:40 by Crusader175
Mind-blowing puzzle!
on 9. June 2022, 21:09 by henrypijames
Reminds me very much of The River by Jakhob and wooferzfg (#9EZ) - one single equal sum line that runs through most of the grid, and of course [SPOILER REDACTED]. :D
on 8. June 2022, 00:07 by tallcat
I am astonished both at the fact that this puzzle was constructed and is solvable, but also at the fact that I managed to solve it (as it's far out of my usual wheelhouse). Astonishing!
on 7. June 2022, 10:16 by kolot
This is complete madness! How on earth did you set this puzzle?! Wonderful job!
on 7. June 2022, 04:34 by Agent
It is incredible that this puzzle exists.
on 6. June 2022, 23:16 by wenchang
https://youtu.be/PFZQysY6uhM
Hard and enjoyable.
on 5. June 2022, 21:39 by hepcecob
Anyone saying that the solve, following figuring out the regions, is in any way tedious, or requires 256 colors to solve, are just wrong. There is a very nice, logical path.
on 4. June 2022, 20:20 by Snookerfan
Wow, what a fantastic puzzle! It was really hard, but so satisfying. I wonder how you great setters are able to keep coming up with these miracles.
on 3. June 2022, 10:47 by Christounet
What a treat ! I think I'd need Bob Ross color palet to solve that kind of puzzle... Amazing construction of the line. I wonder how many lines you may have tried before you found the one that fits. Very well done and thanks !
on 3. June 2022, 03:49 by crispy16
I needed a little prompting to figure out how to get started, but once I did it was a wonderful solve.
Just fantastic.
on 2. June 2022, 21:30 by glum_hippo
The only shape I can make out in the puzzle is a hippo. But I'm glad I solved it, either way
on 2. June 2022, 20:43 by Mr.Menace
What a construction. No easy feat, but very cool idea and brilliant execution! Thanks Jay
on 2. June 2022, 17:17 by Tilberg
@purpl: To the right, there is a phoenix, rising from Arizona.
on 2. June 2022, 16:52 by DVFrank
Absolutely loved it! :^)
on 2. June 2022, 15:37 by purpl
Wowie! What an absolute masterpiece of a puzzle and that line is like some kind of Rorschach test :D what do you see? I see a boot, a kite, a penguin, a sphynix, and the easter island heads!
on 2. June 2022, 13:51 by Niverio
Miraculous. Testing this was an absolute joy. The mid solve is absolutely brutal, but it's already astonishing that such a puzzle can have a unique solution. Take a bow Jay, this one is for the Sudoku museum.
