Tip of the Iceberg (fog)
(Published on 11. July 2025, 18:54 by jwsinclair)
Tip of the Iceberg, by James Sinclair
Normal sudoku rules apply, and all clues are standard.
Dynamic fog: correctly placed digits clear fog from their own cell and possibly other cells.
Cages: the sum of the digits inside each cage is equal to the small number in the top left corner, and digits cannot repeat within a cage. All cage sums are given.
Arrows: the sum of the digits along an arrow is equal to the digit in the connected circle, and these digits can repeat if allowed by other rules. Arrows do not cross or overlap, and all arrow sums are single-digit.
Digits in cells with a shaded square are even.
Digits in cells separated by a black dot have a 1:2 ratio.
Initial difficulty: 3/5
Play online
Originally published in Artisanal Sudoku, Volume 183, and also featured in the Now I Know newsletter!
Solution code: row 1
Comments
on 26. July 2025, 16:01 by isajo4002
WOW! Just when you think that there isn't enough information to continue there's just that one thing that you can do to progress which uncovers more that still doesn't seem enough but is. Amazing work!!!
on 16. July 2025, 02:10 by virus_dave
Very enjoyable, as I'd expect from the author. I'd put at 2.5*, at least twice I was stumped solid and thought I was losing my mind for awhile before something "clicked".
Great fun, thanks!
on 13. July 2025, 11:54 by Franjo
Clever construction! Thank you very much for creating and sharing this lovely FoW.
on 13. July 2025, 07:40 by Crusader175
Neat!
on 12. July 2025, 14:24 by VitP
i found this one intractable, but this is james sinclair, and that's a contradiction.
the "problem" is because i did not SEE a certain graphical element.
this is how it happened.
there is a cell in box 9 that is fogged until you DEDUCE its value and write that in. at this point, the SELECTION element COVERS the critical new info. then i clicked away, and did not look at that cell closely until much later.
in general, one needs to be VERY CAREFUL that one is using all the clues, because the fog confuses the eye-brain interactions.
--
Yeah, that particular step is why I changed the arrow colors. I also made that circle a little smaller (so that the line would be more prominent), but even then it's still easy to miss.
on 12. July 2025, 01:53 by QuiltyAsCharged
Terrific puzzle! It's important to note that cage totals must appear in the leftmost cell of the uppermost row of the cage. (Not merely "top left".) This is explained in the Artisinal Sudoku page.
on 11. July 2025, 22:41 by hardline35
Very nice puzzle! Thank you
on 11. July 2025, 20:44 by Snookerfan
Very nice puzzle full of lovely deductions and traps. Thank you!
on 11. July 2025, 20:13 by Myfyr MJ
Found this one very tough
