Parity Parity
(Published on 3. July 2025, 15:18 by vitaminz)
If you like this rule, I have two other puzzles that combine this with an anti-diagonal rule that I think is quite interesting.
1. Pro-Diagonal
2. Anti-Diagonal
Normal Sudoku rules apply.
Anti-king: Cells that are diagonally adjacent may not contain the same digit.
Dynamic Fog: The grid is mostly covered in fog. Correctly placing digits will reveal the fog in that cell and possibly other cells.
Parity Parity: Beneath the fog is a checkerboard pattern of yellow and blue cells. Each digit appears in one of the colors exactly as many times as its value. For example, 7 will appear either exactly seven times in blue or exactly seven times in yellow.
Solution code: The column number of the 1s in the first 3 rows (from top to bottom)
Comments
on 27. July 2025, 04:00 by TheNineElements
Solve Time: 101:47
I rated this 4/5 difficulty
Really great & interesting puzzle! This was a totally new ruleset to me & I enjoyed it thoroughly!
Saw this featured on CTC and decided to attempt it before watching the video (still haven't watched the video yet) - and I didn't realize that the puzzle was sitting at a 5* difficulty rating (as of now).
I think this puzzle wasn't quite 5* difficulty - although it did take me quite a long time to solve (I typically solve most 4* puzzles in the 1-1.25 hr range). I think the reason it took so long is that I really struggled to "see" the geometry and had trouble coloring everything effectively. I kept mixing up my digit colors & the checkerboard colors.
The actual logic was definitely fair for a 4* puzzle IMO, but it just took me quite a long time to both scan for sudoku & keep track of (and count) which cells belonged to which set (yellow/blue). At one point, I got stuck for around 20 minutes until I realized I had missed some basic Sudoku & a kings move elimination - and I spent that entire 20 minutes coloring 4s and 7s and making minimal progress. In hindsight, if I had started with a more effective/simple coloring scheme, I think this puzzle would have taken me around 70-80 minutes. Other than that one missed step where I got stuck, I felt like the rest of the solve was smooth and generally approachable once I fully "understood" how the diagonal constraints worked.
Regardless of difficulty, the puzzle path was nice & I really liked the idea(s) for the break-in. Surprisingly, I don't think that the main ideas (regarding the yellow/blue sets) were too difficult, and the break-in did a good job of "refining" my understanding of the diagonal logic. I was able to make slight progress at the beginning while still "figuring out" the sets, but at some point the big idea "clicked" for me and the puzzle suddenly became approachable.
Thanks for sharing!
on 7. July 2025, 13:39 by Exigus
Amazing. Took me almost two hours (non consecutitive but still) and well worth it.
on 3. July 2025, 23:39 by ViKingPrime
It's a party in my puzzle and everyone's divided! (into two parities).
on 3. July 2025, 19:50 by Snookerfan
Very nice and extremely hard for me. I probably did it in a totally wrong way, but at least it worked. Rewarding, thank you
on 3. July 2025, 18:08 by Fisherman
Tough. But the solution code is short and sweet. Confession. The fog made the puzzle easier, in my opinion.
