Logic Masters Deutschland e.V.

Modular Yin Yang

(Published on 17. January 2026, 03:20 by 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].




SudokuPad




6x6 Example:

The image below shows a sample 6x6 puzzle and solution with the same rule set.
Play the example 6x6 in SudokuPad.




Solution code: Digits in shaded cells in row 2 (left to right) followed by digits in shaded cells in column 2 (top to bottom)


Solved by tuturitu, Calesch, waffles_the_dog, lianarox, by81996672, sehringdipity, Elliott810, salsais, itweb, Hiyou167, chinesemaster, 85392, Piatato, Snookerfan, redfoot
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Comments

on 17. January 2026, 11:53 by Snookerfan
Great puzzle! For me harder than 3 stars. Thanks

on 17. January 2026, 10:03 by Piatato
Lovely!

on 17. January 2026, 09:13 by Hiyou167
Amazing puzzle

on 17. January 2026, 05:32 by 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

Difficulty:3
Rating:95 %
Solved:15 times
Observed:0 times
ID:000R1I

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