Shading Sudoku Collection
(Published on 10. August 2022, 05:09 by KNT)
Cave: Shade some cells such that all unshaded cells are orthogonally connected, and all orthogonally connected groups of shaded cells touch the perimeter. A cell with a number in its top left corner indicates the sum of the numbers seen in all four orthogonal directions, including itself, where shaded cells obstruct vision. A colored cell is unshaded and indicates the amount of numbers seen in all four orthogonal directions, including itself, where shaded cells obstruct vision. Numbers may not repeat in the field of vision of either clue type.
Snake: Shade some cells such that all shaded cells are connected and form a 1-cell wide path that does not branch or touch itself orthogonally. The path may touch itself diagonally. A cell with a number in its top left corner is unshaded and indicates the sum of numbers in that orthgonally connected group of unshaded cells. Numbers may repeat within these groups. A colored cell indicates the number of shaded cells in the 3x3 area centered at that cell.
Yin Yang: Shade some cells such that all shaded cells are orthogonally connected and all unshaded cells are orthogonally connected. No 2x2 area may be fully shaded or fully unshaded. A cell with a number in its top left corner indicates the sum of numbers in shaded cells in either the row or the column shared with the clue cell. A colored cell indicates the number of shaded cells in the 3x3 area centered at that cell.
Inverted Nurikabe: Shade some cells such that all unshaded cells are orthogonally connected and no 2x2 area is entirely unshaded. Shaded cells form islands, and numbers on an island may not repeat. A cell with a number in its top left corner indicates the sum of the numbers on that island. A colored cell is shaded and indicates the number of cells on that island.
SudokuPad
Solution code: The shaded cells in Row 4 of all four grids. First top left grid, then top right, then bottom left, then bottom right
Comments
on 8. March 2023, 16:04 by Piatato
Great puzzle! Also not too difficult when one during the second try finally more or less remember the rules, haha! :-)
on 26. December 2022, 18:05 by ONeill
Such a fun puzzle!
on 28. August 2022, 02:06 by Christounet
Magnificent !!!
The ruleset is indeed a beast in itself, and a lot to keep in mind along the way. But, coming from a great setter as yourself, I knew it was worth the effort and I’d be rewarded ! Loved the idea of matching the shading between the borders of the grids. And all the little details of the ruleset (May, May not...) that come into play at some point.
Thanks ++ again !!
on 26. August 2022, 08:42 by MagnusJosefsson
Wonderful! What a great idea, and very well executed. Most enjoyable throughout!
on 19. August 2022, 17:53 by Jesper
Very cool combination. Enjoyed it a lot, thanks!
on 18. August 2022, 05:26 by Agent
It was hard to believe that each grid solves uniquely once the inner edges are fully shaded.
on 13. August 2022, 04:50 by thoughtbyte
What a journey - a difficult, beautiful, very rewarding journey. One of the most satisfying solves in awhile. Thanks KNT!
on 12. August 2022, 05:51 by KNT
Made Killer Cave rules more clear, and fixed a typo.
on 12. August 2022, 02:03 by filuta
This is really the ultimate ambiguity idea. I also really liked some unique deductions in the grids on the left hand side.
just one note, even though I understand that the rules are too long for penpa/ctc app to handle, at least some kind of cheat sheet especially what the corner numbers/circles mean in different rulesets would be very useful if included.
on 12. August 2022, 00:29 by Elliptical
In the killer cave rule set, what exactly is the difference between "orthogonal directions" and "orthogonal connections"?
on 10. August 2022, 23:41 by explodingsnail
I got so stuck bc of very silly assumptions I made such as "You can only get the sum of 15 with the cells 12345", forgetting that the unshaded snake sums could have repeated digits and that you could have 2x2 unshaded areas in the killer cave solution LOL. I have a bad memory as well due to my ADHD, so the amount of rules caused me to lose track of them often (which is a problem with me, not the setter <3). When I finally moved past those things, the puzzle was really quite intuitive. Great puzzle, great idea!
on 10. August 2022, 14:00 by DVFrank
Wow, that was quite the journey! I spent a lot of time not knowing where to even begin, but once I figured it out, it was just a a lot of fun seeing the whole grid come to life! Thanks for setting this, KNT :^)
on 10. August 2022, 13:00 by Vebby
Lovely concept! Working out the shading was a lot of fun!
Point of clarification for the benefit of future solvers: All clued cells in killer cave are unshaded and all clued cells in nurikabe are shaded. Circles in snake and all clues in yin yang could be either shaded or unshaded.
on 10. August 2022, 12:14 by DVFrank
I have two questions:
For the Killer cave: Does a cell "see" itself? If it is shaded, does it see anything? (Equivalently, is every clue necessarily unshaded?)
And for the Nurikabe: Are clued cells necessarily shaded?
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Hi DVFrank, the killer cave clue sees itself, and nurikabe clues are indeed necessarily shaded.
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Oh that was quick! Thanks for the clarification! :^)
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Thank goodness for email notifications for comments!
on 10. August 2022, 05:55 by tesseralis
It's a lot to take in at first, but once I grokked it, this had fantastic and fresh logic for all parts of it: disambiguating the puzzles, the edge logic, and the individual puzzles themselves! I would love for there to be more puzzles like this
