Fog and Phantoms
(Published on 20. November 2025, 15:34 by DubiousMobius)
This puzzle was set for Scojo's weekly setting prompt. This time around, Marty Sears challenged us to put together a pack of 6x6 sudokus linked around a central theme, possibly with a story. I decided to combine some ideas from two puzzles I set for impostor challenges. The first centered around invisible clues that were revealed as the grid was colored, and the second revolved around coloring in the fog of war. All feedback is appreciated, and I hope you enjoy!
Your life changed the day you picked up the heavy iron key that now dangles from a chain around your neck. At first, it was whispers drifting in from cabins you know are empty. Then strange shapes dancing at the corner of your vision. Not a very useful affliction for a ship’s pilot. Each day the whispers grow louder, and the chain grows heavier. And when the fog rolled in today, something felt different. The key feels eager. Those shadows in the mist that only you can see? They feel substantial in a way they never have before. Wherever the key is leading you, you know you’re getting close. You just need to chart the course.
The rules vary from puzzle to puzzle, but every puzzle features the following rules:
Sudoku: Place the digits 1-6 once each in every row, column, and 2x3 box.
Dynamic Fog of War: The grid is partially covered in fog. Placing the correct digit in a cell will remove the fog from that cell, and may remove fog from other cells as well.
Phantoms: Some clues are phantoms and may only reveal themselves as the grid is shaded, for this reason, you may only shade the grid once allowed to by the other rules.
As for what those other rules might be? You'll have to play to find out. I did go a little overboard on the visuals, so if you're having trouble seeing the clues, I recommend using dark colors for your shading, and consider enabling the outlines on elements in the settings. Click here to play, or click here for a version without the cosmetics.
You can watch the CtC feature here.
This puzzle wouldn't have been possible without a great deal of help. I want to thank SamuPiano, Donatello_86, and pdyxs for inspiration, Sotehr, PhilTheHat, and The Book Wyrm for help with troubleshooting, and Calvinball, NEWS, ThePedallingPianist for their invaluable help with testing. Not to mention Marty and Scojo for setting the prompt in the first place. Thanks folks!
Solution code: Row 4 of the final puzzle with a / between cells of different shadings. E.g. 12/3/456
Comments
on 23. November 2025, 18:58 by DubiousMobius
One more rule and aesthetic update
on 22. November 2025, 21:14 by silent_rob
Wow - I loved this! Thanks for such a wonderful pack! Innovative in a lot of ways, beautiful and with a compelling narrative. And the puzzles were challenging but fun (and the phantoms were really interesting).
on 22. November 2025, 03:50 by SennyK
I would not suspect 6x6 to be so chellenging and well designed, this is something amazing, loved it so much. Thank you very much for setting this masterpice!
on 21. November 2025, 19:54 by ThePedallingPianist
In. Sane. Aesthetics. Puzzles are really well crafted too, and the phantoms idea is so good and innovative!
on 21. November 2025, 13:15 by Franjo
Thank you very much for creating and sharing this combination of beautiful adventure and puzzle-art.
on 21. November 2025, 04:15 by CitrusGremlin
Call me a fool but I'd turn the key.
on 21. November 2025, 01:13 by vitaminz
Absolutely perfect
on 20. November 2025, 20:14 by TripleABattery
This was so unbelievably cool! Absolutely beautiful, both in terms of logic and aesthetics. I'm blown away, thank you for this gem!
on 20. November 2025, 18:47 by DubiousMobius
Updated rules
on 20. November 2025, 18:29 by Snookerfan
Fabulous! The visuals were stunning and the puzzles marvelous. In the second puzzle I got, and still am, confused by the rule that thermo's do not change colors even though by the other rules they have to. Thank you!
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Whoops! I had penciled that rule in to indicate that the color of the thermometer itself never changed (rather than the regions it visited). Somewhere along the way, I thought I had caught it as being confusing and gotten rid of it, but I must have pulled in an old version of the rules at some point and it made it back in. So sorry, and thanks for the catch! New versions will be uploaded shortly! -DM
on 20. November 2025, 17:25 by Manta-Ray
Wow. Just wow.
on 20. November 2025, 16:54 by Manta-Ray
Wow. Just wow.
on 20. November 2025, 16:37 by SamuPiano
This is one of the most innovative ideas I have ever seen!! What an amazing set - so rich in fresh logic and incredibly satisfying. And, I think this will quickly become the most popular new mechanic in the sudoku community!
I beg everyone to give this pack a try. You won't regret it!
on 20. November 2025, 15:43 by Calvinball
A puzzle pack so beautiful in aesthetics and logic it deserves to be stolen from The Louvre.
