Killer Sudoku - Twirl
(Published on 6. December 2020, 11:18 by Phistomefel)
The usual sudoku rules apply. An area surrounded by a dashed line is called a cage. A number in the upper left corner of a cage indicates the sum of the digits within the cage. Digits may not repeat within a cage.
The puzzle is also available online via F-Puzzles. Have fun solving!
Solution code: 5th row and 5th column
Comments
on 1. February 2025, 01:32 by TheNineElements
Solve Time: 37:29
I rated this 4/5 difficulty
Really nice killer Sudoku. The whole symmetry/geometry led to an early, wonderful deduction that restricted cells around the entire grid. It was a bit tricky to nail down, but I luckily spotted the major restriction(s) fairly early on, in part due to the title of the puzzle. I tried to color it at first, but that wasn't fruitful so I did a bit of experimentation that allowed me to determine polarity (and a bit more information as well, but I wont spoil it here) of the relevent cells and the rest of the puzzle came together nicely.
I think the break-in was probably 4-5/5 difficulty for a killer sudoku, the remainder of the puzzle was around 2-3/5 difficulty for me (still was NOT trivial). The initial major deduction wasn't too hard to spot (its location), but determining its implications was very tricky. Once I had an understanding of it after experimenting with some sums/values, it was very powerful and the rest of the puzzle was much more approachable.
Because the two phases of the solve had different difficulty levels (for me), I decided that 4/5 would be a fair assessment for the overall difficulty. This puzzle took me less time than is normal for 4* puzzles. This is likely because I was attempting to 'speedrun' the solve and I am also fairly experienced with killer puzzles so that did tilt my solve time to be a bit quicker. Even though my solve time wasn't very long (compared to many other 4-5/5 difficulty puzzles), the puzzle was definitely not easy, and the major restriction was very hard to formalize/notate.
Great puzzle & thanks for sharing!
on 12. July 2024, 16:13 by mezkur7
Sudokupad: https://sudokupad.app/golq795apl
on 2. June 2024, 04:59 by KNT
really good killer sudoku! the first digit(s) felt very nice to place.
on 11. January 2024, 17:18 by karlmortenlunna
Absolutely one of the nicest killer-puzzles I've done. Thanks!
on 26. March 2022, 19:53 by Playmaker6174
That was pure madness, but in a very good way.
After the fairly spot-on opening it's still not anywhere near easy and I had to keep track on every spot of the grid consistently, but the result was so rewarding and satisfying. A true hidden gem of its own! ;)
on 28. August 2021, 12:07 by William Cheese
Cool puzzle.
on 28. August 2021, 10:11 by Prutsbeest
To me, this was one of the hardest puzzles from Phistomefel. Glad I finally managed to solve it!
on 4. February 2021, 17:22 by DJdoku
This is outrageously good!
on 17. January 2021, 02:07 by DiMono
I was slow on my solve, but this is such a good puzzle. Thank you for constructing it.
@DiMono: Thanks a lot for solving it and for your kind words!
on 8. December 2020, 17:04 by Phistomefel
@Willy Wonka, @SudokuExplorer, @BcVcB: Many thanks for your wonderful feedback! I think, I will have enough time over christmas to finally make a video on what I learned about setting puzzles.
on 8. December 2020, 16:14 by BcVcB
This was insane! Hope you'll one day make a video of how you create these amazing sudokus.
on 8. December 2020, 03:57 by SudokuExplorer
Wonderful!!! I loved the entry logic and how the logic flowed afterwards. This is without doubt one of the nicest killer sudokus I've ever solved. Thanks :-)
on 7. December 2020, 09:52 by Willy Wonka
Incredible puzzle as always that flows very very nicely. A tough solve but rather achievable despite my limited solving abilities. One of my favourite killer sudokus!
on 6. December 2020, 18:01 by Phistomefel
I am glad you enjoyed the puzzle, cdwg2000 and SirWoezel! :)
on 6. December 2020, 14:58 by SirWoezel
Let’s see... 11.50 to 14.40... one toilet break, one sandwich, one (long) phonecall. I would say just under 2 hours and 30 minutes! Wonderfull puzzle!
Well chosen puzzle-name by the way!
on 6. December 2020, 13:59 by cdwg2000
It is another wonderful problem. C1379 interacts well. Thank you very much for the ingenious ideas of the author! Looking forward to a more wonderful Christmas dinner:-)
