A Sudoku With Just 4 Given Thermometers/Dots

** TODAY'S PUZZLE **
After the fireworks at the end of yesterday's puzzle, we face a sudoku today with just four thermometers of modest length and four dots! It's by GBPack and this is a class construction (that defeated one of our testers).
Play the puzzle at the link below:
app.crackingthecryptic.com/su...
Rules:
Normal sudoku rules apply. Digits along thermometers increase from the bulb end. Cells separated by a white dot contain consecutive digits. Cells separated by a black dot contain digits in a 1:2 ratio (ie one digit is double the other). Not all possible black or white dots are given.
Look out for our video solving the puzzle in Numberphile's latest video tomorrow :)
** JANE STREET INTERNSHIPS **
This video was sponsored by Jane Street who are currently accepting applications for their 2024 summer internships in New York, London, and Hong Kong. You don't need a background in finance to apply. Visit janestreet.com/internships to learn more!
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** SIMON SOLVES KURT HUGO SCHNEIDER'S NEW SUDOKU **
Join us on Patreon (for as little as $2) for a brand new video in which Simon tackles Kurt Hugo Schneider's latest 6x6 sudoku (which you can play at the link below). There's also a brand new crossword video from Mark in which he tackles the latest Matt Gaffney Meta puzzle. You can subscribe for Matt's puzzles at a link below.
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Play Kurt's puzzle here:
app.crackingthecryptic.com/su...
Matt Gaffney's Crosswords:
xwordcontest.com/
** NEW GAS PACK: VOLUME 2 IS OUT **
The new GAS (Genuinely Approachable Sudoku) pack is out on all platforms here:
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60 original puzzles by Clover, Bill Murphy and Philip Newman!! Earn party hats and dinosaurs with these brand new puzzles!
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▶ Contents Of This Video ◀
0:00 Theme music & introduction
1:27 Congratulations to James & Emily!
2:19 Brian Bilston welcomes Autumn
3:57 Jane Street & Numberphile!
5:46 Happy birthdays
7:09 Rules
8:40 Start of Solve - Let's Get Cracking!
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(Please note to use our real names rather than 'Cracking The Cryptic'.)
▶ SUDOKU PAD - Use Our Software For Your Puzzles ◀
You can input classic sudoku puzzles into our software and help support Sven, the programmer responsible for the wonderful user interface we all use to play these puzzles everyday. The app also comes with 12 handmade puzzles from us:
iOS:
apps.apple.com/us/app/svens-s...
Steam: store.steampowered.com/app/17...
Android:
play.google.com/store/apps/de...
ALSO on Amazon: Search for “SudokuPad”
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[@jorlove]

Sorry for the late comment here, but Simon found the intended solve path exactly! He noticed with the semi-roping on the right side of the grid that r3c8 needed to be at least 4, which made the red cells in column 9 all at least 5, which forces r7c8 to be 8. That was exactly what I intended when setting the puzzle. Thanks for the solve! (And yes, GBPack is short for Green Bay Packers)

[@thejadesilly]

How is it.. every time I see you set down with these kind of puzzles with (to me) what feels like absolutely no starting point.. and you argue with it until it just gives up and agrees you're right? I honestly know it's skill, but none the less it's absolutely mind-blowing to watch it unfold, every single time. Great job, Simon!

[@Paolo_De_Leva]

Yes, and this magic "unfolding skill" is particularly fascinating when used to unfold greatly innovative minimalistic puzzles like this, as noted by others (see patrickgass's comment, for instance)

[@patrickgass787]

There's something to be said about puzzles like this, with minimal rule-sets that make use of classic constraints.

[@MyriamTT]

I wish Simon would do more of these.

[@davidmonnerat8598]

Absolutely. I'm not a big fan of Thermos, because they tend to involve loads of pencil marks. But this one got me interested because of the minimalistic setting. And after solving, I have to say, that is a brilliant puzzle!

[@Paolo_De_Leva]

@@MyriamTT Yes, provided they exist. I think these precious gems are rarely found 💎 You need magic to build such an innovative puzzle, when you use such a minimal set of *classic* constraints (thermos and kropki dots, in this case), already used before by so many other genius constructors.

[@longwaytotipperary]

Congrats to James and Emily! ❤ Brian Bilston’s falling tree leaves poem! Enjoyed watching Simon solve the puzzle!

[@RyanAtOptimism]

The Packers *are* an American football team, and Aaron Rogers *was* their quarterback. Well done, Simon!

[@transrightsbaybee]

go pack 💚💛 huge win today hell ya !!

[@bumbalaaa]

@@transrightsbaybeeew

[@zenjaran]

I have a (possibly unhealthy) love/hate relationship with Simons habit of simply not seeing the Sudoku aspects of the puzzles. The number of times I'm just sitting here screaming in my head "But that digit has been clear for ages!!!"... Of course, I generally don't know where I would even start with these puzzles 😅

[@johnathonlillecrapp6480]

So glad it's not just me! Even if I could never even begin this puzzle

[@Pigeon0fDoom]

Its called backseat gaming. Because you can wonder off, you see different things. I have the same and i'm always very proud of myself, but my general skill is no where near Simons.

[@delta3244]

30:20 - I asked a weird question at this point, and found a very fun deduction for it. At this time, without placing any further pencil marks or digits, it is possible to deduce that R6C1 is 2. This can be done by observing that it is impossible to place all of 3, 4, and 5 into R4C{4, 7, 8}. This places at least one of 3, 4, 5 into box 4 off of the box's thermo, and no matter which digit it is, it forces the bulb to become 2. EDIT: on closer inspection, one can do the same with only the digits 4 and 5, which lets one additionally find that R6C2 is 3.

[@Yttria]

Figured out the roping in rows 7-9 but didn't understand the partial roping going on in columns 7-9. After watching how Simon did this was able to apply this new lesson forward into rows 1-3 and finished the rest on my own. Thank you Simon and Mark for all the lessons you've taught us over the years!

[@hewholimpsmartin]

"Tell me why i do it that way." Simon, it's because you're stubborn about doing sudoku while solving sudoku. No judgement - we love you, Sir.

[@matthewhi1205]

The break-in is so surprising and elegant. The video is so enjoyable Simon!

[@kaydeningham4148]

Simon. I always find it really interesting when I see something that you only notice later, because you almost always figure it out by a different way than I did; so I feel like I’m always learning something, and of course, get to continue to be impressed by the magic you can do with a sudoku!

[@pewterhacker]

Surprisingly hard without being unfair in any way. Awesome puzzle!

[@Swisswavey]

Really fun puzzle, most enjoyable. Thanks for sharing it.

[@r0bbiegill]

I try to do these without watching the video first. But there were several points I got stuck, so came to watch the video. And every time Simon got to the same point I had, Simon said something like, “I don’t know what to do next.” Generally Simon’s next thought unstuck me for a while.

[@dollarsing]

Intricate flow. Very enjoyable. Thank you!

[@Mayank3083]

I feel like I have come a long way in 4 months from not being able to put even a single digit to matching Simon's time. I guess I am ready to tackle the 1hr+ ones now. (Was avoiding giving them a shot til now)

[@inspiringsand123]

Rules: 07:15 Let's Get Cracking: 08:44 Simon's time: 27m40s Puzzle Solved: 36:24 What about this video's Top Tier Simarkisms?! Bobbins: 4x (16:54, 16:55, 31:14, 32:22) The Secret: 1x (34:15) And how about this video's Simarkisms?! Ah: 12x (08:12, 15:58, 18:52, 19:05, 19:56, 23:59, 25:09, 27:15, 29:49, 30:11, 32:01, 33:49) Pencil Mark/mark: 9x (08:58, 12:15, 12:41, 24:07, 26:37, 28:40, 29:25, 33:11, 33:57) Lovely: 8x (02:15, 03:22, 03:22, 03:42, 03:42, 26:14, 26:14, 26:45) By Sudoku: 8x (09:40, 10:04, 15:29, 32:27, 32:55, 32:58, 34:18, 35:50) Obviously: 6x (03:26, 06:09, 13:03, 18:11, 24:11, 28:13) Sorry: 5x (00:48, 02:37, 13:29, 18:43, 19:52) Clever: 5x (01:15, 20:06, 26:51, 36:17, 36:19) Hang On: 4x (02:32, 20:02, 20:02, 28:34) Cake!: 4x (06:07, 06:56, 06:59, 07:04) Naked Single: 2x (32:53, 33:39) Recalcitrant: 2x (27:49, 27:52) Brilliant: 2x (26:50, 26:51) Gorgeous: 2x (36:33, 36:34) Shouting: 2x (06:21, 18:46) Beautiful: 1x (36:14) First Digit: 1x (11:37) Puzzling: 1x (04:02) I've Got It!: 1x (02:32) In Fact: 1x (24:15) Which Means What?: 1x (27:01) Chromatic: 1x (36:17) Wow: 1x (31:46) What Does This Mean?: 1x (27:05) Most popular number(>9), digit and colour this video: Ten (3 mentions) Four (52 mentions) Green, Purple (10 mentions) Antithesis Battles: High (3) - Low (0) Even (5) - Odd (1) Higher (2) - Lower (0) Black (6) - White (5) Row (16) - Column (9) FAQ: Q1: You missed something! A1: That could very well be the case! Human speech can be hard to understand for computers like me! Point out the ones that I missed and maybe I'll learn! Q2: Can you do this for another channel? A2: I've been thinking about that and wrote some code to make that possible. Let me know which channel you think would be a good fit!

[@olleicua]

another genius puzzle and an incredible solve. Never would have spotted that break in

[@5t757]

26:44 tonight, I sometimes get very stuck on thermo puzzles like this but this one flowed nicely!

[@davidhughes7174]

Beautiful puzzle and solve. Thank you

[@ericpraline1302]

As Simon remarked, there was some curious and original logic in this one and the relatively few clues resolved themselves very neatly.

[@raysouth1952]

Lovely solve Simon. Very enjoyable.

[@cathybryant5119]

I was thrilled and shocked that I was able to solve this without help from Simon; Completely due to the excellent tutelage of Simon and Mark. This was a very interesting and enjoyable puzzle.

[@BladeQwert]

just incredible, simon does it again

[@oddgarrett2619]

I never know what Simon is trying to establish when he reads out the number of solves a puzzle has had, given that it's only counting solves *in the CTC software*. There's no consistency in how that link is shared - regularly Simon's the first one to have solves it in the software but of course an unknown number of people will already have solved it on e.g. Logicmasters

[@4evafcn]

great puzzle and all the tripple, quadrupple and quintuples coming out of nowhere were amazing

[@Raven-Creations]

That's a really nice example of a thermo puzzle. The geometry was cunning, and each deduction revealed more of the subtlety. This is definitely heavy on basic sudoku, which drives the thermo logic, and the geometry then drives the sudoku. @ 22:54 - "I still don't think I know how to resolve orange" - no, but the tip must be 89, giving an 89 pair in C6. Not surprisingly, it was your sudoku that let you down. You put the 7 in R5, but left a 78 on the thermo in box 6, which would have given you both 8 and 9. This gives you a 69 in box 4, which can be resolved by the dot. Why do you refuse to examine the effect of every placement? It's ridiculous how much time you waste looking for the next move, when you could have been much further along the path. Your reluctance to pencil-mark also means really obvious things just pass you by.

[@evanbasnaw]

I immediately thought of CTC when I saw that Numberphile video with the Star Battle. I'm looking forward to seeing you take that on.

[@thefallenarm589]

18:45 I ruled it out exactly in the same way ; might be the intended logic

[@emilywilliams3237]

I really enjoyed watching this, Simon. Thermo puzzles are very fun and interesting, and you certainly got a lot of lovely logic out of this one. Thanks for sharing the Brian Bilston poem, as well - I have followed him somewhat on social media and agree that he is a very clever poet with great creativity! Thanks so much.

[@ukdavepianoman]

A truly remarkable puzzle. The clues look so simple and almost inadequate....but it solves. A tough solve. Simon did well with the logic. He just needs to clear away his colours so he can see how entering digits impacts his pencil marks (blue on red is very difficult to see)

[@jrparker811]

This is the stuff the best variant sudokus are made of. Minimum given stuff (digits, lines, cages, etc.) and minimum straight forward rules that result in hard but doable puzzles.

[@ingvarsuigin609]

Always thought that "roping" is more like "braiding"

[@piarittersporn]

Brilliant puzzle.

[@stuartharris2165]

Congratulations on the Engagement and Simon don't you want a slice of Wedding Cake?

[@annek3296]

Is "James" the constructor James Sinclair? And I assume Emily is a sudoku fan?

[@theashen]

Got stuck for quite a while after the opening, but solved it eventually, very nice puzzle!

[@michaelholdowsky6386]

A very sweet puzzle!

[@Sam_weiqi]

33:21 for me. Found the logic on the right side quite tricky.

[@deathrow0888]

I can never quite break into these puzzles on my own, all I needed to hear was Simon say "roping" and suddenly I was off.

[@KevFrost]

I had to give up after 90 minutes, then came back to it once I saw I was on the right track thanks to Simon's excellent explanation. My logic succeeded where my pencil marks failed me. 120:42

[@stevesebzda570]

This worked out cool

[@aere481]

Yes, Aaron Rogers played for the Green Bay Packers in American Football, NFL. He was traded this year to the New York Jets amidst a lot of drama. Sadly, he experienced a major injury to his achilles heel and it is possible he may not return.

[@Orenotter]

It seems in the dark I am groping. To solve this strange grid, I'm not hoping. I have not the techniques To defeat it's mystique With its thermos and kropkis and roping.

[@emilywilliams3237]

fun as always!

[@kevinobrien2311]

you are obviously NOT a Cheesehead, Simon. No problem with that!" roping might be close kin to braiding

[@michaelmatter1222]

My favorite part of American football is when the shortstop get's an icing penalty 😇

[@emilywilliams3237]

haha

[@azrobbins01]

I was also hoping you would do the starbattle puzzle as well. I gave it a go after watching the mole video, but could not figure it out.

[@fisheatsyourhead]

Star battles hit a critical point of going from very easy to impossible for me to solve without trying to brute force them, looking forward to seeing what I'm missing!

[@Paolo_De_Leva]

This puzzle is a gem 💎 and Simon unfolds its logic with fascinating magic 👏👏👏👏👏 Magic construction as well‼ It is so difficult to build amazingly innovative puzzles when your options are limited by such a _"minimal ruleset that makes use of classic constraints,"_ as noted below by *patrickgass.*

[@Unchained_Alice]

50:44 for me. Took me a while to see it but it really has beautiful logic from start to finish.

[@stevesebzda570]

37 min vid from Simon. Yay, I have a shot. 😂

[@danielepicone1480]

Well, my performance today was absolutely embarassing, but still posting the time since I had a lot of fun with the deductions. Cleared in 1h00m40s.

[@bertbergers9171]

wow i did it! Just needed some start for the righthand thermo. After that i made good deductions till the end. 49:49 thank you for the video!

[@Antiknight]

Nice puzzle with standard constraints! 00:10:54 for me

[@AFT3RDAY5]

Yes, once the red digits got me started I was getting around. But it really was a tough on for me 😅

[@fisheatsyourhead]

I'm very new to sudoku and this style of puzzle, but they are incredibly compelling and itch a part of my computer scientist logic-loving brain. Does anyone have tips for how to improve beyond practice? What kind of techniques and resources for learning are available? Thanks!

[@jameskarran5330]

I found this hard and very intricate

[@Henni_more]

I feel like negative constraints should be left out and added on if it becomes an actual constraint (like all posible black and white dots are given).

[@mudscuffer]

Broke it at first, restarted and sovled in 24:42

[@moccoX]

Liked, Commended, Subscribed

[@bloodsausage6635]

Hey Simon, I know you probably won’t read this but you’re the reason I’ve started doing sudoku puzzles! You’re incredibly entertaining and I could sit here and watch you solve these puzzles for hours! Thank you for the awesome content :)

[@Rach881101]

30:55 for me. Enjoyable puzzle!

[@_-_-Sipita-_-_]

23:03 for me. it feels kinda unique solve.

[@Kinada]

Cool puzzle. The start felt obvious but then it throws you (me at least) into a sticking point that took me a good long time to see the way out of and it only uses the same logic that you started the puzzle with.

[@hj.0081]

18:36 the way he got the 8, literally speechless, I could never 😶

[@BigAsciiHappyStar]

lol at first I thought you meant any other normal person would say it must be 8 by simple sudoku but after watching the vid I have to agree this was legitimate logic and probably the intended solve path 😀

[@Kirbyfan87827]

Finished in 39:31 with help from the video.

[@srwapo]

33:20, but I had to look at the video a few times. Like, I couldn't see how to use the vertical thermo on the right side, I could see the two digits in Box 3 had to be in Column 9 of Box 9, but didn't see how my pencil marks limited r3c8 to having to be larger than 3.

[@zeldarogers2391]

6:44 thank you so much Simon! We just sat down to watch this puzzle and this was just absolutely priceless. Brandon agreed that the appropriate ratio of cake to icing is 1-to-1 and he’s glad someone finally said it.

[@wanderlustwarrior]

36:54 for me. A bit slower than I'd have liked, given my start, but not bad.

[@karsaanita]

I had the right idea at first, but then it took me ages to figure out that 6 is consecutive with 5 and 7, not 7 and 8...

[@KennethBouman]

15:44 why does the right thermometer have to start with 123, when all the requirements could also be filled with 5 as the lowest value in the bulb? I didn’t quite follow the argument made there

[@NicholasLayton]

Bro is the ceo of yappin

[@aloofmeatloaf1467]

It’s fascinating how very different my solve path was from Simon’s. First, I used some clever deductions so that I was able to limit every cell in boxes 789 to just three digits. Then I got stuck and watched the video so Simon could show me the ropish logic in boxes 3,6, and 9 (thanks, bud). I progressed until I came to an abrupt stop when I needed a Schrödinger cell to continue. So I watched the rest of the video and learned that my original pencil marks in the bottom row of boxes was wrong. So yeah, different solve path.

[@sacredsock8031]

If you are going to Goodliffe the thermometers then don't get carried away with your eliminations

[@creativename3256]

00:20:07 but I assume my real time was about twice of this, as I kept messing up and resetting it 😅

[@user-kt9vr1wj6y]

39:08 for me nice puzzle

[@toddkirby1248]

When is the new app coming out?

[@IllusionOfTrevMan]

Aaron Rodgers is the owner of the Chicago Bears which is an American football team

[@Squishy3757]

Had you marked cells 1,2,3 you’d see they are a 1245 making 789 in cells 456 allowing you to place the 789.

[@shadowstargate]

Do they still sell mercury thermometers in the UK?

[@abdelmalekarzazi2458]

Well after hours of doing sudon'tku puzzle i never see thermometers the same as before anymore

[@Stormorbiter]

It bothers me sometimes when Simon doesn't pencil mark 6 or 7 cell thermos lol

[@CrankyOtter]

I got it started then got stuck. Needed the explanation at 15:40 of where/how the vertical thermo can map & what those digits can be to make any headway. I already overcolored…

[@KennethBouman]

Way late to the party, but why couldn’t that thermometer start at 4 or 5 in the bulb? I didn’t quite follow the logic.

[@Max16hr]

Well, 87:41 for me :)

[@OmegaIL]

Rules start at 7:10

[@Watch3rOfTheSkies]

Simon could do so much better if he took little breaks every once in a while from looking at the “big picture” and just cleaned up his pencil marks and did some good old sudoku.

[@robertcousins2274]

21:08 for me

[@camilogarcia1803]

Why the black dot form the beginning cannot be a 3-6 pair?

[@camilogarcia1803]

Nevermind, just understood. Sorry

[@LednacekZ]

23:04 for me.

[@Gonzalo_Garcia_]

28:54 for me. Terrible solve. Such a shame as well, because the puzzle is fantastic.

[@davidh.4944]

I got the initial roping, and a few other minor eliminations, but I simply could not see how to get anything useful in the top half of the puzzle. I threw up my hands after about 20 minutes.

[@bibliopolist]

As always Simon makes fun of goodliffing, and as always it would have helped to come to many conclusions much earlier... (me, probably not Simon, since he is so bad at reading and understading goddliffed thermos, probably because he doesn't do it often enough...)

[@suewilliams7091]

hello everyone!

[@KaIliev19]

hallo

[@bruceh8043]

26:51 for me and solver #3378.

[@fulltimeslackerii8229]

i think you invented the word “roping” for this pattern. when i first found the channel, you used to call it “striping”

[@patrickgass787]

I find he switches back and forth on the terminology (as does essentially the rest of the Sudoku community). I understand why striping is popular but I've always like the word "roping" for it, feels more evocative.

[@grahamania]

41:48 for me. Clever is a good word for this puzzle! Kind Comment.

[@Pritchie45]

41 minutes

[@MubarkAlKhatlan]

How did you solve it in less than 37 min ? .. I had to guess my way out of it. Edit : I see

[@EchoMirage72]

There hasn't been a Phistomefel puzzle in a really long time.

[@matthewjohnson6360]

Yes, an American Football team I'm a shareholder, he now, plays for the New York Jets but tore his Achilles tendon.

[@neonxvices]

27:50 ooh good word, "recalcitrant". it's going in my list of words i like

[@warren_r]

Soooooo coooooool. 33 minutes and a bit for my solve. I probably saved a couple of minutes by inappropriately using the title of the puzzle as a clue on how to get started.