Negative 8 YY
(Published on 20. November 2025, 17:15 by SennyK)
Puzzle has been featured on Frank Puzzles YouTube channel: link
Another Yin-Yang puzzle with dynamic fog for those who love it :-)
I hope you will enjoy and I would be really grateful for all the comments and ratings.
Normal sudoku rules apply.
Yin-Yang: Shade some cells in the grid so that all shaded cells are orthogonally connected, all unshaded cells are orthogonally connected, and no 2×2 region is entirely shaded or entirely unshaded.
Values: A shaded cell containing digit x has value -x; an unshaded cell containing digit x has value x. In other words, shaded cells have negative values, and unshaded cells have positive values.
Region sum line: Box borders divide a blue line into segments which have the same sum of values. Different lines may have different sums.
Kropki dots: Values in cells joined by a white dot with 8 have difference of 8. Values in cells joined by a black dot are in a 1:2 ratio (i.e., one value will be double the other). Not all dots are necessarily given.
Hint (highlight to see): Black dot can only join two negative or two positive values. 4 and -8 are not in 1:2 ratio.
Killer: Values in a cage sum to the total given.
V: Values in cells joined by a V sum to either 5 or -5. Not all Vs are given.
Dynamic Fog of War: The grid is partially covered in fog. Placing correct digits reveals their own cell and may also lift fog elsewhere in the grid. No guessing is required.
If you liked this puzzle, I recommend trying out my other puzzles: The Erica Series:★☆☆☆☆: 1, 2, 4, 5, 6, 12, 15, 17, 23, 26, 27
★★☆☆☆: 3, 7, 8, 10, 11, 13, 14, 16, 18, 20, 24, 25
★★★☆☆: 9, 19, 21, 22 Shading/Ying-Yang:
★★☆☆☆: Pretty Odd Shaded Area
★★★☆☆: (+5)-Yang, Negative 8 YY
★★★★★: Why-Why? Fog of War:
★☆☆☆☆: Erica 12, Erica 17
★★☆☆☆: It's What You Do in the Dark That Puts You in the Light, Find It All, What the Fog?, Erica 20
★★★☆☆: Broken Flashlight in the Dark Pencil Puzzle/Sudoku Hybrid:
★★☆☆☆: Masyu (Short) Sudoku
★★★☆☆: Tetromino Sudoku
Various Puzzles:
★☆☆☆☆: Blown Fuses in Electrical Installation, Let Me Introduce Myself, French Wrench
★★☆☆☆: Symmetrical Fan, Night Club, Important Hour on the Clock, What Was the Sum Again?, Disgroup Joints, 10-Arrows, Antiking Dutch Skyscrapers
★★★☆☆: Cops & Robbers, Positive Symmetry, Doppelgänger Killer 1-25
★★★★☆: Liars. Liars Everywhere.
Solution code: Ninth (9th) column of the grid from top to bottom (with the symbol "/" marking borders between shaded and unshaded cells, e.g., 123/4567/89).
Comments
on 8. January 2026, 01:37 by Kawkaz
Great puzzle! Not so easy, but so much fun to solve.
on 24. December 2025, 01:41 by dzamie
Had trouble with this one when it first came out, but I returned with more experience with yin-yang, and the ability to take notes on how digits pair off on either side of the 8-dots. Still took a good long while! But it was pretty fun to steadily expand digits and colors through the grid.
SK: Hello dzamie, thank you very much for all your kind words under my various puzzles! Wishing you a Marry Christmas :-)
on 11. December 2025, 22:12 by MattJones
Magnificent! Such a delight, and a lovely, smooth flow. Felt like putting on a brand new pair of posh socks. Loved it.
on 27. November 2025, 13:24 by erml
A masterpiece, thank you!
on 27. November 2025, 04:54 by Voidslime
Very fun! I’ve never colored a yin yang from the inside out before!
on 24. November 2025, 07:53 by QuiltyAsCharged
Terrific puzzle! Keeps you on your toes
on 22. November 2025, 21:54 by samuel1997
Quite a stunning puzzle! Thank you!
on 20. November 2025, 23:18 by VitP
another fine yy puzzle.
fun fact: 2 digits that SUM to 8 also have a DIFFERENCE of 8 ... sometimes
on 20. November 2025, 22:41 by NotSoMagnifique
I stumbled through this one, but it was still lovely!
on 20. November 2025, 22:26 by Cantabrigiensis
Excellent puzzle; thank you very much!
on 20. November 2025, 20:05 by Snookerfan
Very nice! A bit harder than the expected 3 stars for me, which I actually like. Thanks!
