Sudoku Variants Series (298) - Odd Parity Circles Sudoku
(Published on 9. December 2020, 00:00 by Richard)
Odd Parity Circles Sudoku
Inspiration for this type comes from bigger.
Solve online in F-Puzzles (Thx tubahat!) or in Penpa (Thx Nick Smirnov!).
Apply classic sudoku rules.
In all cases where in an area of 2x2 exactly 3 odd or 3 even digits appear, a circle is placed on the intersection of the grid lines of that area. The digits in the circle have to be placed on a diagonal in such an area. Within a 2x2 area digits may repeat.
Solution code: Row 4, followed by column 1.
Comments
on 19. December 2021, 08:04 by Richard
Added links for online solving. Thx tubahat and Nick!
on 22. November 2021, 18:31 by Nick Smirnov
Penpa:
https://git.io/J1QL0
Unlike tenaliraman I think this sudoku decreases in terms of difficulty. The first steps include some tricky bits, but after that it becomes very easy.
on 14. December 2020, 18:43 by Bankey
Delightful variant ! Thanks, Richard!
on 10. December 2020, 14:19 by telliott
Great puzzle, thanks. The negative constraint rules supreme in this one.
on 10. December 2020, 11:55 by tenaliraman
I love how the puzzle increases in terms of difficulty as you keep solving the puzzle. Very educational in how a puzzle must be designed :-)
on 9. December 2020, 22:04 by SudokuExplorer
Delightful logic! Thanks for making yet another very enjoyable puzzle :-)
on 9. December 2020, 17:04 by washyleopard
@tubhat
When you click export just click copy compressed link.
https://f-puzzles.com/?id=y3m8ll76
on 9. December 2020, 16:56 by tubahat
https://f-puzzles.com/?id=y3m8ll76
on 9. December 2020, 15:20 by Fedo
I had fun solving it, thank you for this!
on 9. December 2020, 13:44 by PetLov
So OK, I feel like such an idiot :-)
Reading the rules properly is a good idea.
Thank you all for clearing this up to me.
on 9. December 2020, 13:31 by cdwg2000
@PetLov
It can be solved by using negative restrictions. It is not recommended to use uniqueness before the additional conditions are used.
on 9. December 2020, 13:28 by bigger
I don't think there is a deadly pattern. 579 and 6 have different parity, and the rule said 'in all case'. so it's not possible, unless the pattern strictly has one parity
on 9. December 2020, 12:38 by PetLov
This puzzle is nice, however I ended up with a deadly pattern of 5, 7, 6 & 9.
@PetLov: what do you mean with a deadly pattern? Guessing is not necessary and the puzzle has one unique solution... ?!?
***In my solution, which may be incorrect somewhere but correct enough to enter the solution code, I can swap the digits in R1C4 & R1C5 and all the digits that follows after that swap and still get a valid solution. As I said, I probably missed something somewhere.
***Thank you cdwg. That is indeed what I missed :-)
on 9. December 2020, 01:00 by CountSudokula
Richard, can't wait for # 300... maybe it should be called THIS IS SPARTA!! :)
