A Foggy Day
(Published on 21. November 2025, 17:57 by googuee)
Normal 9x9 Sudoku: Place the digits 1-9 exactly once in every row, column, and 3x3 box.
Fog: Some grid cells are hidden by "fog" meaning you cannot see their contents. Some fog will be revealed when a group of cells is correctly filled. The intent of these puzzles is to make logical moves rather than guessing and using the fog reveal to know whether you are correct.
Kropki Dots: Digits separated by a black dot have a 1:2 ratio, meaning one is exactly double the other. Not all dots are necessarily given.
Renban Lines: Purple lines in the grid are Renban lines. Digits on a line form a set of non-repeating, consecutive digits in any order. Renban lines in this puzzle are not allowed to make any turns.
German Whispers Lines: Green lines in the grid are German Whispers lines. Adjacent digits along the line must have a difference of at least 5.
Arrows: There are circles in the grid with attached arrows. The digit in the circle is equal to the sum of the digits on the attached arrow. Multiple arrows stemming from the same circle are to be treated individually. Digits are allowed to repeat along the arrows as normally allowed by other rules. There is exactly ONE arrow circle in this puzzle.
Thermometers: There are filled circles in the grid with connected thick lines called thermometers. The circle represents the bulb of the thermometer. Digits must strictly increase along the thermometer starting from the bulb end. There is exactly ONE thermometer in this puzzle.
XV Sums: Digits separated by a V must sum to 5, and digits separated by an X must sum to 10. V and X are the Roman numerals for 5 and 10, respectively.
Solve online at this SudokuPad link.
Check my other puzzles here.
Solution code: Row 9
Comments
on 23. November 2025, 18:25 by h5663454
I don't know how ridiculously difficult the puzzle were before the changes...:/
But after playing the revised version, in terms of difficulty, 1 star is too low, 2 stars is just right.
----
…But in any case, the rating is meaningless for this puzzle anymore :/
on 22. November 2025, 19:13 by Marshal on Mars
Definitely was not expecting the puzzle to open up *quite* that much where it did. Haha.
Re: VitP's #3: I think the solution to that would just be resubmitting the corrected puzzle and removing the broken puzzle rather than keeping the same entry and updating the link. It doesn't seem reasonable for LMG solvers to all go back and adjust their rating if a link gets updated (particularly considering LMG does not notify you if a puzzle you have started has its link changed).
It also just strikes me as odd to say that difficulty ratings are too low and assume everyone is an expert while you yourself are saying this is a 1-star difficulty puzzle.
on 22. November 2025, 18:38 by VitP
not your usual comment.
first, the basics.
1) with the rules correction, and the 2 additional clues, the puzzle now solves very easily, and is "almost gas", so level 1.
2) ALWAYS get the product tested before release.
and now, the part that will make people uncomfortable.
3) many of the ratings on this site are basically meaningless. most common is that the difficulty ratings assume that everyone's an expert. that is fundamentally false, and claimed difficulty is often much easier than actual difficulty.
often, the quality rating is considerably lower than is appropriate. in THIS case, with the puzzle being broken initially, i can see a low rating, but the puzzle NOW is good or better, and the rating should reflect that.
4) and look at the RECORD. it plainly shows that i was the FIRST to point out the mistake. BEFORE that, SIX people claimed that they had solved an unsolvable puzzle. this is the first clear proof of something i was suspecting for a long time.
on 22. November 2025, 17:35 by googuee
I have updated the rules based on the community’s feedback.
I also added a few extra constraints to make the ending of the puzzle more approachable and easier to follow.
The puzzle's difficulty rating has been adjusted accordingly.
on 22. November 2025, 16:47 by googuee
As many of you have pointed out, my assumption about the Renban not being able to extend was incorrect, and the end of the puzzle turned out harder than intended. A few additional constraints would have definitely helped. It is clear the puzzle needed more testing before being published. Thank you all for your feedback and sorry for the pain I put you through :)
on 22. November 2025, 16:40 by Myfyr MJ
Very nice but the end was brutal.
on 22. November 2025, 14:00 by SennyK
Hi, what seemed to be a lovely puzzle turned out to be a pain due to several Y-wings with so many cells in the grid without fixed digits.
Also, this puzzle is honestly unsolvable due to assumption you have made which is not correct - I also did this once, however put my puzzle through the testing and it was caught.
Namely, when you reveal R4C3 being a single cell with a renban going up and down - you have assumed that it cannot turn, though it can - and it can therefore acquire full set of digits 1-9.
You can easly fix this by stating in the rules that all renbans are straight lines and they cannot turn - then it can be used as intended.
For me 4* and not very enjoyable due to ending after grid has revealed - though the fog part (putting aside a broken renban) was lovely and without the Y-wing ending I would rate this as very nice puzzle.
on 22. November 2025, 11:09 by VitP
you can do some work in the bottom 3 rows, but then the clues run out.
is this a joke?
perhaps you forgot to state that the partially revealed renban is exactly 3 cells long? that's NOT a valid assumption
on 22. November 2025, 10:42 by Martina
3* for me. I don't know if it was intended this way, but I solved it using the ring.
on 22. November 2025, 04:06 by rychuuu123
My first 3* sudoku I solved. It wasn't easy at all for me.
on 22. November 2025, 00:26 by fishsaltyak
I got nothing after the fog clears.....
Edit, eventually got. Sorry, but the second half of this puzzle was not enjoyable at all.
on 22. November 2025, 00:02 by Myfyr MJ
Very nice but the end was brutal.
on 21. November 2025, 23:17 by shikage5
Smooth solve right up until the end--I keep forgetting that you can use classic sudoku inferences in tandem with variant sudoku XD
on 21. November 2025, 20:31 by PinkNickels
Sublime. Very neat logical path and the ending was trickier than expected. Very nice setting!
*** Glad you enjoyed it!
