Ring of Kropki dots
(Published on 8. December 2024, 15:44 by egubachu)
Rules
- Sudoku: Place the digits 1 to 9 once each in every row, column, and box.
- Kropki dots: Digits separated by a black dot must be in a 1:2 ratio. Digits separated by a white dot must be consecutive.
Solve online
A related no-solutions puzzle
Related to the actual puzzle, I have also prepared a "no-solutions" puzzle with a similar arrangement of black Kropki dots. In no-solutions puzzles, your task is to prove that there cannot be a solution to a a given arrangement of constraints. Click the image to try it on sudokupad.
Thanks
Thanks to sujoyku for valuable feedback during testing!
Watch on Youtube
Thanks so much to Crusader Puzzle for covering Ring of Kropki dots on his YouTube channel (in Indonesian)! Watch it here!
Solution code: Row 6
Comments
on 5. February 2025, 08:40 by Crusader175
Brilliant puzzle and thank you for the shout-out!
on 17. December 2024, 16:54 by puzzlepandit
Nice construction. Other than maths, I have to use almost every trick that is there in sudoku.
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Thank you so much for your nice compliment puzzlepandit! I had good fun with all this trickery wile setting this puzzle:)
on 10. December 2024, 18:30 by Norkas
Very cool and inventive pure Kropki. There was a lot more to this one than one might expect at first glance.
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Thank you so much Norkas! I'm so glad you appreciated my Kropki puzzle! I've been meaning to set a pure Kropki puzzle for a while, and had some good inspiration this time!
on 10. December 2024, 04:49 by skuntsel
Perfect setting! The flow of logic back and forth around the grid is simply amazing. A very delicate setting, something that doesn’t matter much initially plays a significant role later on. Center box logic is especially satisfying.
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Thank you for the great compliment skuntsel! I saw that central cell logic and knew I had to go for it!
on 9. December 2024, 23:38 by mihel111
Lovely break in and fluent solve after that.
Very good work, Egubachu.
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Thank you so much mihel! I'm glad you liked my puzzle!
on 9. December 2024, 23:03 by Chaka
Oh yes! It seemed to be a simple ruleset at first glance but turned out to be just brillantly set! Thank you so much for sharing this with us, egubachu!
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Thank you so much for the wonderful compliment Chaka! Setting this puzzle was lots of fun! At first I set out with the arrangement of black dots, with the goal of letting beginners explore logic around the Phistomefel ring, without them having to know about the Phistomefel ring or how to prove the set equivalence. The ring just emerges for you. But then beautiful logic emerged for me! The puzzle still doesn't require you to use the set equivalence of the Phisomefel ring, but I decided to keep the logic around the ring and go for a 3* puzzle with the cool logic.
on 9. December 2024, 13:33 by moHa
Lovely puzzle! Quite hard for me personally but i really enjoyed it! Thank you for constructing this
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Congratulations on the solve moHa! It's definitely not an easy puzzle, featuring some unusual logic for a pure Kropki dot puzzle. I'm so happy that you loved it so much!
on 9. December 2024, 09:01 by Snookerfan
Gorgeous setting! Thank you
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Thank you so much Snookerfan! I'm so happy that you enjoyed my puzzle!
on 9. December 2024, 08:33 by Srinidhi Kabra
Wonderful puzzle! Loved the geometric discoveries along the way. A nice lesson in how asymmetry leads you to solutions!
There's also an easy way to understand why the no solutions puzzle or in fact any puzzle with complete symmetry wouldn't have a unique solution. We can enter whatever digits we want, and rotate it by 180 degrees. And we will get another valid solution, but this time, the row 5 would be flipped! Thus giving us at least two solutions (note that the row 5 cannot be palindromic as that would violate sudoku rules)
on 9. December 2024, 03:52 by JDP678
Absolutely gorgeous puzzle - loved it!
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Thank you so much JDP678! I'm thrilled that you loved my puzzle so much!
on 8. December 2024, 23:39 by SamuPiano
Cool geometry!
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Thank you so much SamuPiano! I'm happy that you liked the journey around the grid with the deductions!
on 8. December 2024, 21:52 by antiknight
Great construction!
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Thank you so much antiknight! I'm so happy that you appreciate the setting!
on 8. December 2024, 21:22 by Myxo
Beautiful!
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Thank you so much Myxo! I'm thrilled that you loved my puzzle!
on 8. December 2024, 21:01 by ademjaz
Lovely!
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Thank you so much ademjaz! I'm so happy that you enjoyed the puzzle!
on 8. December 2024, 20:57 by PinkNickels
I am shocked at how good this puzzle is! What tremendous setting talent
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Thank you so much for your wonderful comment PinkNickels! You're making my day!!
on 8. December 2024, 19:26 by Killer-Ly
Beautiful logic. Loved it!
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Thank you so much for your wonderful comment, Killer-ly! I'm so happy that you appreciate my puzzle so much!
on 8. December 2024, 17:59 by sujoyku
Very nice and quite tricky puzzle. Thank you for setting and sharing, egubachu!
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Thanks so much for your comment and for your very helpful testing sujoyku!
on 8. December 2024, 17:58 by AnomanderKarsa
ﹰﹰvery nice
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Thank you so much AnomanderKarsa!
