8x8=9x9
(Published on 13. August 2022, 17:30 by filuta)
Huge thanks to ctc discord users DarthParadox, samish, rotobagel and KNT for the time they spend testing either version of the puzzle and their valuable feedback.
Enjoy the puzzle, I will be happy to read your comments.
-fill in the grid with digits 1 to 9 with no repeats in any row or column,
-draw nine - potentially partially or completely overlapping - orthogonally connected areas (of size 9) each containing digits 1 to 9 once each such that each cell is a part of some area,
-digits on an arrow sum to the digit in the corresponding circle where each digit (both on an arrow and in a circle) is considered multiplied by the number of areas it belongs to.
To avoid any confusion - there are three arrows joining at r7c7 (starting at r6c5, r7c5 and r8c6) with a joint tip at r8c8. No arrow goes through any circle.
Solve the puzzle online via:
ctc app
penpa+ (or an extended version with a separate grid for indicating areas)
Solution code: Row 3, then for every domino in row 6 (from left to right) the number of areas it belongs to (so how many areas contain both r6c1 and r6c2, then both r6c2 and r6c3 and so on) - 15 digits total.
Comments
on 29. October 2023, 13:47 by wullemuus
Phew. What an incredible monster! I'm far away of telling that the breakin was easy. Figuring out the CC construction was quite hard as well. The arrows and the given digits were really very well chosen contraints. And the function of cells with multipled digits to build up unusual grids was extraordinary. Wow!
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Thanks, congrats for the solve!
on 23. September 2023, 14:19 by halakani
This puzzle is so good that even entering the solution code is a tiny puzzle by itself. 10/10.
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haha, thanks a lot, yeah, finding a good idea (and formulation) for the solution code was a little challenge for me too
on 12. July 2023, 03:35 by SXH
This is my first time commenting on LMD because this Sudoku is too powerful. I can't help but express my admiration for it. It is the most difficult Sudoku I have solved so far, and I spent 389 minutes solving it.Great puzzle, thanks!
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Thanks a lot for the comment. Yeah I absolutely get what you are saying I needed like two months just to find enough courage to make it.
on 24. June 2023, 09:34 by Yann
I did it! What a beautiful puzzle! The break-in wasn't too hard, it was important to consider every option, and the rest of the solve is "quite" straightforward (because I missed some obvious deductions about which digit was missing in a certain row/column, so I wandered into the realm of mini bifurcation, but not totally). I still think that this puzzle is harder than misfits, but not because of the complexity of the solution path, but because of the rules, it's easy to overlook an option. The region building was so miraculous I actually wondered how many attempts it took you to have a unique grid. In any case, thanks for setting this (the 12th hardest sudoku in the portal), and I look forward to trying to solve the third twin or friends in unknown lands.
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Thanks a lot for the comment. Yeah I really hope I will manage to add the third part of the series, its quite scary though. But maybe I will manage, when the first anniversary of this one is coming.
on 2. April 2023, 01:35 by Myxo
What a mind-blowing puzzle! Thanks for setting.
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Thanks a lot, it was a real pleasure to watch your solve.
on 1. November 2022, 13:31 by polar
A totally astonishing & unforgettable puzzle! The smoothness of the solve path after the break in is spectacular. Thank you very much! :)
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Thank you so much! I can't explain with words how happy such a comment makes me, and coincidentally you solved this puzzle at the same day I finished setting of the next one in (now apparently) the series. What a great day!
on 25. August 2022, 19:05 by Jesper
Great puzzle, thanks! Very challenging, especially the start. Astonishing how well it resolves in the end.
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Thanks a lot!
on 18. August 2022, 16:12 by MagnusJosefsson
Amazing puzzle that is truly a very different experience from any other I have solved on this site. Very challenging but also extremely rewarding.
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Thank you so much!
on 15. August 2022, 20:36 by Vebby
Extremely tricky. Solvers need to be careful what regions are possible / where region overlaps may lie. Very impressive construction.
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Thank you!
on 13. August 2022, 18:55 by filuta
changed solution code description
on 13. August 2022, 18:42 by KNT
Fascinating puzzle, one of the most deviously tricky break-ins I have ever seen. To my surprise, the puzzle flows very nicely once you lay out some initial groundwork.
Assuredly one of the most unique puzzles I have ever solved, and it was a pleasure to test, despite having absolutely zero idea what to do for the first hour of my solve.
on 13. August 2022, 18:29 by Samish
This puzzle is a full journey through this daunting ruleset, that carries us through the full range of emotions only the very best puzzles can give. Absolutely amazing
