Modular Yin Yang
(Eingestellt am 17. Januar 2026, 03:20 Uhr von yttrio)
Rules:
Normal Sudoku rules apply.
Yin Yang: Shade some cells such that all shaded cells are orthogonally connected, all unshaded cells are orthogonally connected, and no 2x2 area is fully shaded or fully unshaded.
A digit in a cell with an arrow counts the total number of shaded cells seen in the direction of the arrow (not counting the cell itself).
For every 2x2 area in the puzzle, no two shaded cells can be from the same modulo 3 set. In other words, in any given 2x2 area, there can only be one shaded cell with a digit from [147], one from [258], and one from [369].
6x6 Example:
The image below shows a sample 6x6 puzzle and solution with the same rule set.
Play the example 6x6 in SudokuPad.
Lösungscode: Digits in shaded cells in row 2 (left to right) followed by digits in shaded cells in column 2 (top to bottom)
Kommentare
am 19. Januar 2026, 22:17 Uhr von dzamie
Cool! The break-in made me really glad that I've already solved a number of yin-yang puzzles, since it got me a lot of shaded/unshaded cell pretty quickly that I wouldn't have known otherwise.
am 17. Januar 2026, 20:05 Uhr von firespire
I didn't tune into the "key fact" until later but still very enjoyable puzzle.
am 17. Januar 2026, 18:48 Uhr von Fool on Hill
Lovely puzzle - yet more fresh logic. I tuned in to a key fact quite quickly, which helped a lot.
am 17. Januar 2026, 18:04 Uhr von Exigus
Very nice construction, had a great time solving. Thanks!
am 17. Januar 2026, 16:24 Uhr von Ambrose
Wonderful setting and fun interactions!
am 17. Januar 2026, 15:54 Uhr von mihel111
Yin Yang puzzles have something more. That more is yttrio. Thanks a lot.
am 17. Januar 2026, 14:21 Uhr von marcmees
Outstanding puzzle. Thanks
am 17. Januar 2026, 12:56 Uhr von Franjo
Thank you very much for creating and sharing another great YY-puzzle with perfect setting.
@VitP: the modular constraint is only for the shaded cells.
am 17. Januar 2026, 12:37 Uhr von VitP
in the 6x6 example, box 3 is broken with {14}.
more importantly, for the main puzzle, the constraints are too weak to call it even level 3
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The modular restriction only applies to shaded cells. The 1 and 4 in box 3 in the example are both unshaded, so the constraint doesn't apply to those cells.
~yttrio
am 17. Januar 2026, 11:53 Uhr von Snookerfan
Great puzzle! For me harder than 3 stars. Thanks
am 17. Januar 2026, 10:03 Uhr von Piatato
Lovely!
am 17. Januar 2026, 09:13 Uhr von Hiyou167
Amazing puzzle
am 17. Januar 2026, 05:32 Uhr von waffles_the_dog
Really fun puzzle, an interesting break in, the solve path was really nice though I did have a few Simon-vs-Sudoku moments :D
