Killer Sudoku - The Knot
(Published on 31. August 2020, 23:10 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: 4th and 7th row
Comments
on 26. January 2025, 01:05 by TheNineElements
Solve Time: 37:06
I rated this 4/5 difficulty.
Really interesting, unusual (in a good way), and fun killer sudoku! I really struggled to make progress for around 25 minutes, but while playing with some sets, I spotted a restriction which really cracked open the puzzle for me. Took some arithmetic and coloring, but eventually I nailed down the entropy of several digits around the grid. It was definitely hard to find, and was a 4-5/5 difficulty deduction to spot in my opinion.
Once I found that trick in the "early" stages/"break-in" (took me nearly 70% of the total solve time to make any real progress) the remainder of the puzzle felt around 3/5 difficulty. The 'break-in' was such a big proportion of the solve that dividing the rating between the break-in and midgame was difficult. I suppose the break-in had multiple 'phases' where I was trying different things out - but really I had a good idea of what cells/areas and cages were restricted from an early stage. The difficult/interesting part was proving/showing which cells were restricted, and to what degree. It took a lot of trial and error, but once I found a good means of coloring the geometry, it seemed 'obvious' in hindsight. I used SET principles to find the restriction, and the simplicity of the final SET deduction was elegant.
Due to the complexity/difficulty (in spotting the restricted digits) of the puzzle I decided to give this an overall difficulty rating of 4/5.
The restriction I found was really cool, and something I haven't seen before. I enjoyed how it was a really 'broad' scope - as the geometry spanned nearly the entire sudoku grid. I think that played a role in making such an impact on the solve following its discovery. The rest of the solve following the major deduction was also very nice, and I enjoyed having a big payoff for my "discovery".
Thanks for sharing!
on 24. June 2024, 10:48 by mezkur7
Sudokupad: https://sudokupad.app/dr3ioy0awx
on 25. September 2023, 00:31 by Piatato
Very clever construction, really a flawless puzzle!
on 24. September 2023, 22:00 by CrazyCrypticC
Absolutely stunning. A masterpiece.
on 15. September 2021, 08:07 by Prutsbeest
Very very nice puzzle indeed. Took me quite a lot of time to get all of the right ideas, but I finally managed! Thanks for this one!
on 21. August 2021, 18:43 by Phistomefel
Added tag "Online-Solving-tool".
on 20. August 2021, 09:36 by LordM
Verzweifle seit Tagen am Einstieg. Vielleicht ein dezenter Hinweis, wo ich hinschauen muß?
on 23. February 2021, 16:35 by ogi.djukovic
Shoutout to PixelPlucker for recommending me this puzzle
on 29. January 2021, 00:51 by SudokuExplorer
Luckily I spotted the entry quickly. Thanks for the fun puzzle! :-)
on 9. September 2020, 16:46 by Phistomefel
@Ragna: Dankeschön! Das freut mich, wenn es dir gefallen hat. :)
on 8. September 2020, 01:54 by Ragna
Super - Puzzle!
Together with Simon so wunderfull :-))
on 3. September 2020, 19:55 by vdwestdg
2 days of my life on that entry!!;) Looking forward to your next challenge
on 1. September 2020, 21:29 by Statistica
Ganz großartig!
on 1. September 2020, 08:36 by Phistomefel
Thank you all for your kind words. :)
on 1. September 2020, 03:22 by cdwg2000
Nice entrance！
on 1. September 2020, 01:14 by henter
Great stuff! Delightful solve from start to finish
on 1. September 2020, 00:26 by Willy Wonka
I'm going to be happy the rest of the day because of this solve! Very very enjoyable, thank you!
I have made a puzzle with the same idea but most definitely not of this quality. This is a great demonstration of why so many people has fallen in love with your puzzles!
