Indexification (Dyn Fog)
(Published on 4. February 2025, 15:19 by Fenners)
I normally get quite boggled with index cells, so I thought I'd have some practise setting a puzzle with it as a prominent rule. I found by the end it started to sink in! Also, learnt to implement dynamic fog for the first time!! Enjoy and any feedback very much welcomed.
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Puzzle: Indexification
Rules:
Normal 9x9 Sudoku rules apply. Place the digits 1-9 once each in every row, column and 3x3 box.
Dynamic Fog: Correctly placed digits may or may not clear fog from the grid.
German Whispers: Adjacent digits along a green line must differ by at least 5.
Killer Cages: Digits in a cage cannot repeat
Indexers: A blue cell in row X indicates the row where X appears in the column. A red cell in column Y indicates the column where Y appears in the row. A blue AND red cell acts as a blue cell and a red cell at the same time.
Solution code: Row 9, left to right, no spaces:
Comments
on 14. February 2025, 23:11 by dzamie
Nice! Dynamic fog works really well with this. My only troubles were self-inflicted: forgetting which color went to which axis.
on 6. February 2025, 02:11 by fishsaltyak
So much fun!
on 5. February 2025, 21:34 by rainingfish
The use of the dynamic fog had me second guessing myself at first, but once I got going I found the various constraints interacted quite beautifully!
on 5. February 2025, 04:12 by kirb
I agree that this was certainly challenging for someone unfamiliar with indexing (i.e. me!). It took me a while to figure out, but afterwards was a very nice solve :)
on 5. February 2025, 00:39 by MarthaB
Fantastic puzzle!
on 4. February 2025, 23:42 by mmm
I don't understand the indexer rule. Could someone explain it to me? maybe with an example
Fenners: Take the red cell in the bottom left of the visible box. This is in column 4. Place a 7 in it. Then the 4 must go in cell 7 of that row. Now place a 2 in it. Then the 4 must go in column 2 of that row. The same is true for the cyan cell in the upper corner except it indexes the column. This cyan cell is in row 4. Place a 7 in it. Then the 4 goes in cell 7 of that column. Place a 2 in it. Then the 4 goes in cell 2 of that column.
Think where does the digit go along the row (R) for red (R). Think where does the digit go down the column (C) for cyan (C). I know it's more of a blue but it helps me remember.
on 4. February 2025, 22:22 by therealsillypenguin
Great puzzle! Personally, I disagree with the below commenter, and think 1* is fair, as it's pretty easy if you're familiar with index puzzles.
on 4. February 2025, 20:35 by PinkNickels
Very fun! Clever setting.
on 4. February 2025, 20:29 by anyeyeball
I love indexing sudoku, and this is a great one. Thanks for sharing.
on 4. February 2025, 20:28 by softie
That was certainly mind-boggling. No way is it 1*!
Fenners: I originally categorised it as as 2* but the people have spoken. I think it could go either way depending on familiarity with indexing.
on 4. February 2025, 18:01 by Wuschel
Beautiful, great use of fog. I loved the striped cells.
