The Longest Possible Thermo
(Published on 31. May 2026, 23:50 by Sudokujoker)
When I first discovered slow thermo rules, it made me wonder... just how long could a slow thermo be? The answer is: very long!
Normal sudoku rules apply: place the digits 1-9 once each in every row, column and 3x3 box.
Slow Thermo: Along a grey thermometer, digits must either increase or stay the same, starting from the bulb.
Sudokupad link: https://sudokupad.app/gnl2w3121h
Solution code: Row 9
Comments
on 5. June 2026, 00:41 by Sudokujoker
Thanks to everyone for the ratings and feedback!
Regarding the harder finish, I felt that was necessary to balance out the -ahem- very easy start. As others have noted, there are a couple of specific things to spot, but bifurcation shouldn't be necessary.
I believe the title isn't too much of a "spoiler" - when I solve thermo puzzles I'd start by counting the length of long thermos anyway.
Thanks! If you enjoyed please check out my other puzzles :)
on 1. June 2026, 21:31 by Narayana
No bifurcation needed here. I think the little thermos are just right to make it nice-path-solvable without giving too much info.
Rating it very nice, not sure if the "low" score is from people who bifurcated or from people mad at the spoiler in the title ¯_(ツ)_/¯
on 1. June 2026, 18:06 by Snookerfan
I really liked the hard step near the end, the rest was fairly obvious, as a 1 star puzzle should be. Thanks
on 1. June 2026, 18:02 by Geoloco
Agree with most other comments that there is a surprising bite to this puzzle near the end. although I ultimately solved it without bifurcation
on 1. June 2026, 16:02 by TVDK
Fun puzzle, pretty straightforward. Definitely no need to bifurcate.
on 1. June 2026, 14:11 by RussKozerski
The comments make it sound like a bit of a struggle. And I have a hard time with anything more than 1-star difficult. But I found this fairly easy, with no bifurcation. Maybe I got lucky, but it seemed pretty straight-forward to me.
on 1. June 2026, 11:36 by MartinR
Nice easy start, but tricky near the end - didn't need to bifurcate, but had to notice some key cells and the impact they had.
on 1. June 2026, 11:18 by Myfyr MJ
Very nice and reasonably easy. Pay attention to box 7 as that was the break in for me. ;)
on 1. June 2026, 11:10 by anothermember
I found it all fairly trivial until one point near the end - probably the same point others have found. Hard to see a way through that without bifurcating.
on 1. June 2026, 11:04 by VitP
this claims to be level 1.
the brick wall in the middle proves otherwise
on 1. June 2026, 09:51 by JVA
Maybe I'm having a bad case of the Mondays, but progressing past the long thermo wad quite hard, had to bifurcate both boxes 3 and 7
