You CANNOT and MUST NOT Solve This Sudoku

** OCTOBER MONTHLY REWARD - OUT NOW **
The Duality Sudoku Hunt was released yesterday. Massive thanks and kudos to the Sudoku Skunkworks for creating such a brilliant set of puzzles (14 in all). You'll be able to enter the competition if you can solve the first 4 sudokus. If you solve all 14, you'll get a shoutout.
We've also just released Simon & Mark's solve of Vignettes by zetamath, which you can play at the link below:
app.crackingthecryptic.com/su...
Join us on Patreon to watch the video for as little as $2/month here:
/ crackingthecryptic
** TODAY'S PUZZLE **
Mark sends Simon through another of his prank sudokus today with Chameleon's Quantum-safe Sudoku. This is absolutely bonkers. The idea is that you cannot solve it (!) but figuring out how to not solve it is... quite hard!!!
Play this extraordinary "sudoku" at the link below:
app.crackingthecryptic.com/su...
Rules:
Normal sudoku rules apply. Cells separated by a black dot must contain digits in a ratio of 1:2 (ie one digit must be double the other). Cells separated by a white dot must contain consecutive digits. Not all possible dots are given. Cages are “Schrödinger cells” ie they contain one of 2 values. After filling all regular cells with digits, all Schrödinger cells must remain unresolved (in other words, both values of every Schrödinger cell must allow for a valid sudoku solution). The quantum balance of the universe is safe with this sudoku. Cats are safe too.
[Note there is a tiny change to the rules above vs those which Simon faced in the video. We used "allow for" rather than "lead to". We do not think this will affect anyone's solve at all but we just thought it might clarify one tiny aspect of the puzzle.]
** GET OUR NEW FREE APP AND/OR WATCH US STREAM IT **
To celebrate achieving 500k subscribers, we're trying to say thank you in a couple of ways.
We've released a FREE app full of handmade puzzles - simply download the Cracking The Cryptic app on Android, Steam or App Store and then select the 500k pack. We're streaming a playthrough of this app and you can watch the first four episodes here:
• Simon & Mark Solve Sud...
• Simon & Mark Solve Sud...
• Simon & Mark Solve Sud...
• Simon & Mark Solve Sud...
We'll be streaming the next episode TONIGHT at 10pm UK time.
We're also able to offer our Cracking The Cryptic Greatest Hits book at a discount for a limited period. (Books are now in very short supply).
The coupon code is “500SUBS” and it can be redeemed at checkout here:
coffeebean.games/ctc-greatest...
** Our New App Is OUT **
Our new app is OUT on App Store AND Android AND ON PC (via Steam)!!
We've completely revamped the interface. Now you download the basic app free and you can choose to download additional content. So there's a FREE pack of puzzles by Prasanna Seshadri and a paid pack: DOMINO SUDOKU!!!
apps.apple.com/us/app/crackin...
play.google.com/store/apps/de...
store.steampowered.com/app/20...
▶ Contact Us ◀
Twitter: @Cracking The Cryptic
email: [e-mail]
Our PO Box address:
Simon Anthony & Mark Goodliffe
Box 102
56 Gloucester Road
London
SW7 4UB
(Please note to use our real names rather than 'Cracking The Cryptic'.)
▶ SUDOKU PAD - Our New App ◀
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”
**************************************************************
▶ CTC FAN DISCORD SERVER◀
/ discord
▶ OUR BACK CATALOGUE - ALL CATEGORISED WITH LINKS!◀
tinyurl.com/CTCCatalogue
▶ NEW CRACKING THE CRYPTIC MERCHANDISE◀
teespring.com/en-GB/stores/cr...
▶SEND US PUZZLES TO SOLVE/CONTACT US◀
[e-mail]
▶FOLLOW US◀
Twitter: #crypticcracking
@crypticcracking
Instagram (for how to solve daily clues from The Times): crackingthe...

[@chameleon_yura]

Thanks so much for solving my puzzle! I didn't even hope for it to land on the channel. Clarification about the interpretation of the rules: it's totally ok to have multiple "deadly patterns" at the end ("both values of every Schrodinger cell must lead to a valid sudoku solution" doesn't mean that the puzzle must become unique after putting a digit into 1 Schrodinger cell).

[@aikiseppuku]

Don't understand why Simon is playing so dumb. Even after having drunk some wine, the rules are pretty clear and easy to understand

[@MisterNohbdy]

I don't check Logic Masters very often, but I'm glad I randomly did last week when this was posted. Brilliant puzzle.

[@XPDolphin]

I was just coming to comment that the rules say valid solutions, not only two valid solutions. Given Simon's solution, it seems there are 4 valid solutions resulting from this. Truly amazing. Good work.

[@jesperwillems_]

The wording ‘must lead to’ does heavily imply that by filling in a cell it automatically gets you a solution. Luckily this ‘misinterpretation’ of the intended rules doesn’t break this wonderful puzzle, and with a finished grid in front of me it did become clear what the intent was; but i must agree with that wording it “must allow for a valid solution” does take away this ambiguity

[@UltraLuigi2401]

Perhaps change it to "both values of every Schrodinger cell must lead to _at least one_ valid sudoku solution" to avoid this confusion.

[@yerel_nimni_avni]

It's not a deadly pattern but rather it's both deadly and lively pattern until you open the box.

[@chameleon_yura]

So true

[@KevFrost]

But you have to be careful which of the 9 boxes you open

[@megauser8512]

Nice!

[@jovaji72]

Simon in any video so far: there are no such things as Schrödinger cells in Sudoku. Chamaleon: hold my beer.

[@andrewsoteriou8230]

🤣🤣🤣

[@axolotl1973]

Not sure if someone had to hold it since he have showed that he could just gandalf his way through any sudoku under the influence.

[@FluffSWE]

there has been another puzzle on the channel with a different kind of Schrödinger cells. so this is puzzle 2 :)

[@chameleon_yura]

There are lots of brilliant Schrödinger cell puzzles out there, I definitely wasn't the one to invent the concept :)

[@gregind01]

Yesterday negative numbers, today Schrödinger cells, what facet of impossibility will we be dealing with tomorrow?!

[@dominikbeitat4450]

I've just come to realize that watching Simon solve this puzzle is like watching someone fall in love. You don't understand what's going on, most of the time you think you're doing it wrong, never does anything seem to make sense. Yet you're mesmerized and terrified the whole way through, and while you've only figured out half of it at the end, the remaining ambiguity is the most beautiful thing you can imagine.

[@christopherstark887]

What a beautiful comment!

[@ellaenchanted2399]

THAT WAS AWESOME!!!!!!!!!!!! Also, you know CtC has reached stardom when people are making puzzles essentially to troll Simon and Mark. Perfection, Perfection, Perfection!

[@inspiringsand123]

Rules: 01:08 Let's Get Cracking: 08:36 What about this video's Top Tier Simarkisms?! Schrödinger Cell: 15x (01:04, 01:28, 01:36, 01:44, 02:07, 02:15, 10:39, 10:49, 27:38, 29:19, 29:30, 37:01, 1:28:55, 1:31:48, 1:32:03) And how about this video's Simarkisms?! Ah: 24x (02:21, 10:41, 11:35, 22:04, 23:56, 38:54, 45:13, 45:13, 45:17, 49:21, 53:14, 56:49, 1:01:51, 1:01:58, 1:12:17, 1:16:11, 1:18:02, 1:18:52, 1:19:10, 1:20:05, 1:25:32, 1:26:04, 1:29:55, 1:31:58) Hang On: 11x (02:01, 20:21, 21:55, 21:58, 31:32, 31:32, 31:32, 38:51, 56:49, 1:01:19, 1:02:30) Obviously: 11x (06:30, 08:16, 09:03, 12:38, 13:31, 38:08, 52:33, 55:40, 1:02:48, 1:10:40, 1:13:11) In Fact: 10x (00:26, 13:53, 28:36, 28:36, 54:29, 54:29, 1:04:37, 1:07:25, 1:16:27, 1:20:17) Wow: 10x (02:52, 05:57, 40:37, 53:23, 53:23, 1:03:42, 1:03:42, 1:12:25, 1:12:25, 1:28:12) Sorry: 8x (23:40, 48:09, 56:56, 1:03:00, 1:17:16, 1:17:16, 1:24:38, 1:29:57) By Sudoku: 8x (1:03:26, 1:03:51, 1:04:22, 1:08:23, 1:09:19, 1:18:55, 1:21:45, 1:23:29) Brilliant: 6x (05:45, 06:01, 07:43, 07:46, 08:20, 58:40) Good Grief: 3x (02:38, 37:23, 1:23:13) Nonsense: 3x (25:29, 1:22:19, 1:22:24) Deadly Pattern: 3x (02:58, 09:40, 1:10:38) I've Got It!: 3x (53:26, 53:29, 58:46) Progress: 3x (08:43, 23:43, 1:09:43) Fabulous: 3x (07:04, 07:04, 08:18) Symmetry: 3x (41:46, 42:02, 42:31) Goodness: 2x (02:18, 1:30:31) Clever: 2x (1:34:38, 1:35:34) Beautiful: 2x (42:52, 1:03:48) Break the Puzzle: 2x (13:36, 14:03) Incredible: 2x (08:51, 08:53) Extraordinary: 2x (1:19:17, 1:35:08) Surely: 2x (14:13, 55:32) Stunning: 2x (07:02, 1:06:02) Nature: 2x (33:42, 1:16:19) What on Earth: 1x (1:07:52) Bother: 1x (1:02:13) Apologies: 1x (1:24:08) The Answer is: 1x (45:10) I Have no Clue: 1x (34:16) Horrible Feeling: 1x (1:08:09) Insane: 1x (44:20) Fascinating: 1x (1:15:19) Take a Bow: 1x (1:35:18) Epiphany: 1x (1:25:23) Of All Things: 1x (1:03:51) Corollary: 1x (48:34) Unbelievable: 1x (1:00:08) Marries Up: 1x (39:47) Internal Logic: 1x (03:58) What Does This Mean?: 1x (47:00) Unique: 1x (03:30) Most popular number(>9), digit and colour this video: Ten, Twelve, Fourteen (2 mentions) One (135 mentions) White (18 mentions) Antithesis Battles: Even (27) - Odd (4) White (18) - Black (16) Column (45) - Row (34) 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!

[@venomthegirl2006]

At 1:03:49 I like the interpretation that, since this is a Schrödinger--themed sudoku, Simon is both doing and not doing sudoku at the same time :)

[@AlonAltman]

This puzzle is a really good way to brush up on your group theory. While a pair (AB/AB) and triple (AB/BC/CA) have only one way to mix them without set points, 4 cells can consist of either: AB / AB / CD / CD (two 2-cycles) AB / BC / CD / DA (one 4-cycle) This does mean that if you know 3 of the pairs you can always figure out the 4th one. 5 (e.g. row 4 of the puzzle) is can be a 5-cycle (AB/BC/CD/DE/EA) or a 2-cycle and a 3-cycle (AB/AB/CD/DE/EC). 6 can consist of 2x 3-cycles, 3x 2-cycles, a single 6-cycle, or a 2-cycle and a 4-cycle.

[@technoneko8108]

Well put

[@henkkamerman1920]

Thats exactly what I was thinking. Simon at 1:13:00 puts a 36 in row 4 because he sais there needs to be one. But if I see it correctly, the row could have a 5 cycle which Simon did not think about: 23567 for example: 23/26/35/67/57

[@danwil316]

@@henkkamerman1920 He needed to put a 3 and a 6 in r4c5, r4c7, and r4c9 to make the 6 in r4c1 ambiguous and the 3 in r4c2 ambiguous. But r4c5 and r4c9 both see 36 pairs.

[@henkkamerman1920]

@@danwil316 ahhh yeah, I didn't see the 36 pair in box 5. Thanks!

[@stephan9120]

Is it determined that there are just two digits per cell? A triple could be ABC/ABC/ABC or not?

[@HunterJE]

So glad Simon had the presence of mind to pick letters for this one, imagining this solve path with colors 😱

[@HunterJE]

Especially because Simon’s not precious about removing letter marks that’ve done their work whereas he insists on not only leaving colors but carrying them forward after they’re not actually contributing

[@spacelem]

​@@HunterJE I like the colours persisting, it helps break up an the white and give some structure to the grid!

[@simonbergqvist]

I did it with colors. Wasn't bad at all. I would actually say that the visual helped a lot to see in which lanes you couldn't put certain numbers/colors.

[@AnElt999]

1:21:07 OK, I can believe Simon's new glasses haven't spotted 6 pair in col1 and 5 in the corner, he is busy with deduction 1:23:20 Doing crazy sudoku with 6, but still can't see five in the corner 1:24:19 "In theory this 57 pair needs to be resolved. So strange this" 5 in the corner: *still hiding from new glasses*🗿🗿🗿 Simon, you are so brilliant, I love the way you hate doing sudoku in sudoku

[@JuanEstradaGiuria]

1:18:54 he puts a 2 in row 3, witch it would get the 5 placed on the white dot, and the 4 in box 5, setting off a mini chain reaction of 1s and 4s. It was there for 6 and a half minutes! I almost went crazy

[@kelperdude]

Simon, here's a tip for you. When you gave out the link to Sven's channel, I went over there and asked him how to deal with showing clues outside the box, such as sandwich or diagonals, as being 'used'. His suggestion was this: Try using the pen tools and placing small crosses on the outermost edge. You even have multiple colours to use!

[@heart.9889]

That works great, i've been doing that! Generally the pen tool is great for adding information to the grid!

[@RoselynTate]

I've already been doing this -- it works a treat, because it doesn't cause confusion for other clues within the grid

[@robert-skibelo]

Very good tip. But I'll eat my hat if Simon ever reads it, acknowledges it, or adopts it. Good tips from viewers go nowhere on this channel, at least not in the comments. Maybe if you had a way to email him...

[@SethStiebinger]

Or... discord?

[@bristolrovers27]

These rules are just incredible, I suspect Chameleon is very smart just to think of this rule set let alone create a puzzle using it.

[@jsmirob]

Oh, I guarantee you that from the moment Simon first used the phrase "Schrodinger cell," every setter who watches this channel has thought about making a puzzle like this. I know I certainly have. Actually doing it, though, is something else entirely.

[@dolf370]

@@jsmirob He he, it's like when he says about German Whispers that there can not be any 5 on the line because the neighbor would have to be 0 or lower or 10 or higher, and such things does not exist in sudokus. I just get this burning itch of creating a sudoku with 0s and 10s.

[@fornife5004]

When Simon says it is not part of Sudoku rules.. it is a red rag to a constructor.. and they run with it.

[@jarnokylander490]

These long and challenging solves are the reason why I watch the channel. And you don't take our time, we give it to you.

[@jasonfire3434]

After seeing this now I hope someone makes the ultimate Schrodinger Puzzle for Simon where every single cell in the grid has exactly two options and he’s forced to pencil mark to Goodliffe levels without resolution 😛

[@Gonzalo_Garcia_]

Omg thank you so much for your kind words, it’s such a thrill to hear that coming from you. I strongly encourage everyone to have a go at Duality themselves, it’s probably the best pack you’ve ever released.

[@Cpchurch87]

Is it on the app store, or patreon? I haven't signed up for patreon yet but I feel the time is right

[@yellowtrumpetfish]

The Pyramid puzzle hunt was amazing though as well ❤

[@Gonzalo_Garcia_]

@@Cpchurch87 It's on Patreon. If you enjoy their daily content you should definitely check it out, there's some awesome stuff in there.

[@gunrugger]

Would you mind uploading a solve or two? I hear you're fast! That could be fun to watch!

[@AFastidiousCuber]

Here's a weird observation: This Sudoku variant might be computationally harder than other variants of Sudoku. Most Sudoku variants, like classic Sudoku or killer Sudoku, are in the NP complexity class, because proposed solutions can be verified quickly. Whereas here it seems highly nontrivial to determine, in a proposed solution, whether each option for every Schrödinger cell yields a valid grid.

[@keejay98195]

it’s still easy to verify by trying out both options for each cell

[@keejay98195]

problem still lies in NP

[@joshkeegan3009]

@@keejay98195 np, but more difficult to program

[@AFastidiousCuber]

@@keejay98195 Not necessarily. Once you place one digit, the rest of the grid becomes a classic sudoku, which is itself NP-complete to solve. Of course though, we're talking about generalized n^2xn^2 grids. If you went through every cell and tried both options, using standard algorithms to solve the resulting grid, it would take exponential time to verify.

[@keejay98195]

@@AFastidiousCuber gotta have a think on this, what complexity class do you think this would be in?

[@Robert_H.]

0:08:38 Start 0:14:45 Labeling with letters 0:15:30 Solve the Schrödinger cells in the first three columns 0:49:47 Break letters and get numbers 0:53:23 Breakthrough 1:01:44 Get the last Schrödinger cells 1:15:05 Do Sudoku 1:31:50 Puzzle solved

[@Gonzalo_Garcia_]

I stared at this puzzle for like an hour and gave up, there’s no way I could have figured out the break-in. Absolutely mental, way beyond my possibilities. Very interesting to watch Simon solve it, though. Great video!

[@andrewcook8093]

The way to think about the shrodinger cells is that in each row, column and box you need to split them into cycles. A pair being a length two cycle. So a column with four schrodinger cells can be split into two pairs(pairing the digits up)or one length 4 cycle.

[@columbus8myhw]

And a length 4 cycle looks like [AB][BC][CD][DA] in some order. A consequence is that each letter appears exactly twice.

[@sacredsock8031]

you can tell a puzzle is tricky when Simon is reluctant to colour

[@keyaanmatin4804]

I'm going to run out of popcorn at this point

[@Krytom42]

*reads title* - You can't tell me what to do! ✊ I'll solve it! - *opens puzzle* - ......oh dear...

[@stevel875]

Although I didn't attempt the puzzle this time, one observation that would have helped during the earlier part of the solve is that each schrodinger digit must appear exactly twice in each row/column/box. Simon was entertaining the idea of having (e.g.) AB AC AD in the same column which is not possible as having a third A means that at least one of B C D must be restricted to a single cell.

[@mghiduc]

The black dot from the lower left corner gave me the 14 pair in just two minutes (with the help of the two white dots I've solved de 124 or 248 dilemma). Waiting 50 minutes for Simon to find it was both depresing and satisfying. A very Schrodinger feeling.

[@pandorah_]

I'm glad that Chameleon gets some well-deserved attention for this masterpiece! It's so clever, yet so minimal in terms of clues. Took me just under 40 minutes :)

[@th.nd.r]

One of the most brilliant puzzles of the year. I’m gonna have to keep an eye out for Chameleon’s next channel feature. The novelty of the ruleset, the beautiful solve path, the unique mind you have to have to come up with this, just beautiful. Wonderful solving as well Simon, thank you for being diligent and not giving up, we are all blessed to have witnessed such a piece of art. Just utterly mind blown.

[@wariolandgoldpiramid]

This puzzle was just absolute madness. Got easier towards the end though. The beginning was such a crazy Matrix Metaverse, that I wasn't able to fully follow along Simon's solve, and just had to trust that Simon knows what he's doing. But as the solve progressed, I was able to get an understanding of what we're doing, and even yell at the screen at the "obvious pencil mark" clues Simon was, as usual, not noticing. Brilliant puzzle, Chameleon. And amazing brain power on your part, Simon.

[@charliemcadams07]

Simon, the ONLY thing i dislike about the long solves are your apologies! Please dont apologise , do longer ones!

[@MusikCassette]

finally some one did Schrödinger cells right. and by right I mean, that this puzzle is actually useful to explain superposition and entanglement. great job.

[@madeleinearancibia]

2.5 hours! With Simon's help a few times. I LOVED this puzzle.

[@uncgoalie]

Amazing how Simon displays pure brilliance for a whole hour and then stumbles through the easy part... he should have colored all the cages to keep them out of his mind I guess... (other than the XY ones)

[@dinane]

At the end there I’m just muttering “row 8!!!” I loved this puzzle so much and actually enjoyed Simon’s increasing self confidence. Starting from no understanding to “that’s great!”❤

[@dinane]

And now at the end “have I actually done this or not?” Is like exactly the point!

[@leojs5673]

it’s election day here so i think it’s safe to say CtC is about all the logic and reason i’ll be seeing on my phone for the day 🥴 excited to watch this one!! hope everyone has a nice sunday

[@felipevasconcelos6736]

absoLUtely, eLections Are insane here.

[@leojs5673]

@@felipevasconcelos6736 hahah apertei 13 pra ver se essa insanidade de quatro anos acaba logo

[@AvatarBowler]

Agreed. I especially hope the Brazilian left wins big. Solidarity to them.

[@AugustoValentini]

I'm watching the video while anxiously waiting for the results to start coming lol I really hope it ends today and we don't have another 4 weeks of campaigning, because I think I'll go insane if we do.

[@felipevasconcelos6736]

@@AvatarBowler “left” and “big” are relative terms, considering how many concessions Lula is making to the center, but I agree with the sentiment.

[@Cpchurch87]

I can solve all GAS puzzles with respectable times. Most videos up to around the hour mark I can usually solve (eventually) any phistomefel or a video over 90 minutes is usually out, but I’ll always give it an initial go or let Simon show me the break in then attempt from there. This puzzle; I didn’t even bother trying 😂

[@Nikanuur]

I opened the puzzle, read the rules, and said to myself "this sounds like Simon's problem" closed the puzzle to sit back and enjoy Simon solving it

[@Sakamori14]

To construct this, Chameleon really thought outside of the box, to realize he/she cannot know what is in it.

[@christieh8697]

I'm just proud that I was able to keep up with the video! I'll never understand how people make these.

[@vladspellbinder]

58:30 This is the laugher found in the happiness of madness. Just under an hour to work out a way to APPROACH the actual solving of the puzzle and find the internal logic needed to work a solution. There is a reason the line between genius and madness is so thin. I foresee a lot more puzzles with Schrodinger cells so really the software needs an update where you can show them with something like (1~4), meaning the cell is 1 AND 4 at the same time and not that is 1 OR 4 like a normal 14 notation means and for the software to be able to validate if the solution is correct or not. Not an easy task but doable with the right thinking. Thanks for the video Simon, hope your sanity has recovered.

[@ImaginaryMdA]

Oh this was so much fun! I never thought I could feel comparable joy to Simon over a Sudoku, but this was just fantastic.

[@GraemeMcRae]

I haven’t even watched this video yet, but already I have a comment: keep these long videos coming! I can’t tell you the joy I experience on seeing the video length.

[@nightwishlover8913]

That's OK - I CANNOT!! Love the rule about cats!

[@LongplayCentral]

"This is like a massive massive horrific matrix of nonsense" is the best thing I've heard on internet all week!

[@sondang2412]

56:18 I think an easier way to put the 2 in box 1 is that C has to be in r2c3 because there's an X-Wing of C in column 1 & 2. Then we can deduce that C cannot be 4 because if it's 4 it'll eliminate candidate B from r2c2, which breaks the Schrödinger-ness.

[@Ardalambdion]

Yesterday we talked about the display used by programme developers and sudoku setters. They should let people with sight issues test both the software and other features. And I wish Simon good luck with his glasses tonight.

[@lomax343]

Notices that it takes Simon an hour and a half to solve this. Thinks: No.

[@Dragonlord446]

Ikr

[@luckass90]

Reading the ruleset -> checking length of video -> grabbing popcorn and sit back

[@Kamiyurikai]

Wow that was a mind bender of a puzzle and a literal beauty in a box..... The idea to involve schrödinger cells is making the puzzles ever more convoluted yet ever more interesting 🤔. Simon you deserve a standing ovation. Please take a bow my good man to solving yet another mad genius puzzle out in the sudoku world. 11/10 for effort and logical pathfinding.

[@bradleyreed8876]

When you put XY in box 6, you could also deduce XY in row 6, which leads to a few other things a bit quicker. Great puzzle and great solve!

[@birkheadc]

Yeah I'm quite disappointed Simon missed a chance to say he had an "X-Y-Wing"

[@thomashjelm2928]

@25:24 "This is like a massive, massive horrific matrix of nonsense" 😄

[@clcovill]

This is stunning! I didn't try this one, but I was so amazed at the rule set I knew it would be a fascinating solve. Loved it. Such a great puzzle/video to keep me company while I study for midterms!

[@reubenmckay]

The beauty of puzzles like these is that no matter how ludicrous they look on first inspection, Simon WILL force a logical solution (thus also trolling Mark's attempt to troll him in the first place).

[@selenasilverstep7981]

1:04:00 "This is a 1/4 pair now, by Sudoku... Have we been doing Sudoku?! That is a philosophical question." I'm actually laughing out loud this is peak comedy

[@Megatron9000]

Now that was an engaging solve! I've saved this one to solve myself a few months down the road if I can somehow allow it to evaporate from my memory! Doubt I'll be able to forget it though, it was so cool! What a concept!

[@HalfBakedLunatic]

Absolutely wonderful to watch this. I suspect that authoring it wasn't as hard as Simon is imaging ... it's relatively easy to find an "ending pattern" that exhibits this property, and then just work backwards. When I see videos of famous setters explaining their flow, they always say to start from the beginning and design the break-in first but I think this puzzle was created the opposite way!

[@GeoffCanyon]

Simon, Chameleon, you are both geniuses. This is a remarkable puzzle and you should both be enormously proud.

[@359Aides]

Ever since Simon jokingly started talking about cells not being able to be Schrödinger cells I've been waiting for someone to pick it up and make pretty much this exact puzzle :D Great job on setting it!

[@pekuja]

30:00 Couldn't you organize those four digits something like: AB, BC, CD, AD ? Then if the first one is A, the fourth is D, third is C and second is B, and if the first one is B, the second is C, the third is D and the fourth is A, and there's no "odd one out" in either case.

[@HunterJE]

Agreed, he tried to do a cycle and just messed it up, then assumed a cycle was impossible

[@johnedwards7473]

I'm still watching to see if he figures this out. I guess he doesn't?

[@callindrill]

Don't feel bad for the long video, Simon. You did wonderfully, and I certainly love these longer (and more interesting) solves! You definitely do not take up "too much of [my] time!"

[@joelstevens5670]

I feel for Simon with this sudoku. There is quite a simple approach provided you can focus on one aspect of Schrödinger cells, pairings (that if a digit A is present then there must be a digit B which prevents A from being determined). However, the idea of Schrödinger pairings is so crazy (since the digit pairings can mix with each other) that it is very easy to miss. If you label one AB as ‘A’ and the other as ‘B’, it becomes easy to see where ‘A’ and ‘B’ go, then ‘C’ and ‘D’ etc. Simon’s mistake was to use a third digit too early. Having said that, the video was very helpful because of the 1248 logic which reassured me at the tricky midpoint of the solve (also the fault of that pesky third digit). So well done Simon on sticking with it and my apologies that this comment is so late compared to the video release (a puzzle as brilliantly mad as this one deserves a comment).

[@janeflett4971]

Thank you, great puzzle, I did use a bit of trial and error at the start figuring out which of 124 or 248 was on the black dot in box 7, but then worked out one of the Schrodinger cells in box 1 had to be odd, and the solve flowed like magic from there.

[@gregind01]

36:00 Simon might it be time for Mark to solve a Phistomofel live and opened on camera?! Congratulations Simon on finally having the bravery to put up a solution to a sudoku you claim to have solved, yet you have left many of the digits unresolved! 😁🙃 Enjoy your bottle of wine with the live stream this evening, you have earned it.

[@johnpauladamovsky86]

*OUTRAGEOUS* Miscarriagement of taxitude...!!! - Lucius Sweet. The story behind this puzzle is ridiculous. A couple years ago, Simon Anthony came up with a clever way to describe what happens in a regular SUDOKU when you try to force 2 different digits into a single cell. He said, "there's no such thing as a Schrodinger Cell... NOW there's a whole genre of logic puzzles called Schrodinger Cell SUDOKU. This particular puzzle is the crowning exemplar of the new genre. Well done Chameleon...!

[@CaptainSpock1701]

1:28:03 - You know this is a beast. We have a fully pencil-marked grid from Simon after almost 90 minutes.

[@chiarabernardi2705]

I'm sorry did anyone else catch at 25:28 "this is like a horrific matrix of nonsense?" I almost snorted my icecream out of my nose. that describes my everyday a little too much thank you sir

[@lexyeevee]

after a couple very poor starts, i came back to this after a few months and solved it in about 45 minutes, and i think it might be one of my favorites now :)

[@J_Squatch]

This is the first one I've played along with, and I'm glad I did. It was an absolute blast to puzzle through.

[@mukaiba1]

"Have we been doing sudoku? That is a philosophical question..." I don't think I've laughed harder! A new SimMarkism if I ever heard one! 😂😂🤣🤣

[@markp7262]

46:37 finish. What an absolutely incredible idea for a puzzle! I was going to talk about the X-wing on Cs, but it's already been mentioned. I wound up coloring the different Schrödinger cells, giving the ones in columns 1 & 2 dual colors (everything else was able to be a single color). So much fun, brilliant!

[@wdvorak]

One thing that strikes me about first visual inspection of this puzzle ... all of the Schrodinger cells are paired (in column or row) except in row 4 and 9, and in columns 1 & 2 ... all the other Schrodinger cell essentially being X-wings.

[@shteevuk]

We do love the long videos Simon!

[@wydadiyoun]

just by reading the rules this sounds like a genius! How the hell could one think about such an idea and moreover implement it! I am looking forward solving this apparently genius puzzle with probably the most creative ruleset I have ever seen!

[@andersosterholm2538]

Wow! What an amazing, and crazy, construction! And an impressive solve! Thank you chameleon and Simon for this video.

[@noelwalterso2]

If anybody had told me that a one and a half hour long video of someone solving a puzzle could be interesting I would have thought they were having a laugh.

[@lylecampbell8288]

I used both letters and colours when I did this to distinguish between distinct states like AB and BA, and both were helpful. I used one colour for AB and a different one for BA. With the letters I used one corner mark and one centre mark so that I could distinguish AB and BA. Then the two states are the corner marked state and the centre marked state. This let me propagate the colours/letters much further through the grid.

[@Mn0ty]

A helpful way of thinking about this puzzle is to sometimes change perspectives. If there is Schrodinger cells (cells wich must contain exactly two possible values), then, the opposite is true: ther are Schrodinger digits (digits wich must appear twice in the box, the row and the box).

[@philipnitschko9093]

You know the Moment when you spot something in the Puzzle and Simon or Mark did not yet spot it? I would have loved to see Simon spotting the Schrödinger-X-Wing on X's (and Y's though ^^) But as always such a joy to see them solve such a brilliant Puzzle.

[@elroyjennings7833]

54:20 for notation I am using I knew A and B had to be 1 and 4 with C=2 because of the white dots in box 1 from when you pointed out that in box 1, the Schrodinger cells with the white dots were AE and BD. The white dot and uncertainty from the Schrodinger cell implies that A and E are 2 apart and that B and D are 2 apart. Look at the AE cell specifically, the other cell in the white dot must be between A and E. Which gives that |A - E| = 2 Because 2 white dots appearing in box 1 that implies there are 2 pairs of sequential digits in box 1 which can share no common digit. Next, as you pointed out, A, B, C must be 1, 2, 4 or 2, 4, 8. If A B and C are 2, 4, 8. Then there is a contradiction That leaves 1, 3, 5, 6, 7, 9. As the remaining digits. The only sequential pairs of digits are 5, 6 and 6, 7. However we need 2 pairs of digits that share no common digit. Therefore A, B and C must be 1, 2, 4. Going further. When A, B, C are 1, 2, 4. The remaining digits are 3, 5, 6, 7, 8, 9. Leaving 3 pairs of sequential possibilities (5,6) , (7,8) ; (5,6) , (8,9) ; (6,7) , (8,9). I believe solutions with (8,9) create contradictions. I'm going to stop here. I believe I see an error in my first proof. I am going to post as is. I have to go.

[@OlafDoschke]

I bet Schrödinger didn't only own a cat, he also had several chocolate teapots.

[@danielwcrompton]

Loved it Simon!

[@MarushiaDark316]

I think an easier way of conceptualizing this puzzle - and probably how Chameleon came up with it - is that whenever you have two cages, they must be a pair. If you have three cages, it's a triple. If you have four cages, it's a quadruple, etc. Those quadruples could be pairs or they might not be, and you could imagine working backwards from a puzzle that had lots of deadly patterns in it to get to the starting point, you're just highlighting where they are in the beginning.

[@carlossosa2907]

Yes, I think he got misdirected by the nature of the clues, the disposition of the cells indicated their parity.

[@emilywilliams3237]

So, let me start by saying that "mental" does not begin to describe this puzzle. I could not understand what was going on for ages. Ages. At some point you began to figure out what happened in column one and I began to think that I understood what was going on - but no way in my lifetime will ever be able to do this. Maybe in heaven I will understand this! But YOU, Simon, are just amazing ... I was going to say "as always" but this goes beyond any "always" I have yet experienced on this channel. I will now also add that, were this the very first video I ever watched on this channel I would have been very, very puzzled. This was least like sudoku as I knew it before being directed to CTC by my son that I have ever seen. So anyone who is new-ish to CTC and variant sudoku, this was not typical of what usually happens in these videos - this was beyond the stars, beyond the end of the galaxy in its complexity, and even the most complex other videos on this channel are much more like sudoku-as-we-know-it (do you hear the echos of Star Trek: TOS in that?) than this. You will love it here - come back again and again and you will find so much to delight you. And then, after a month or two, come back and watch this again, and you will get it (much better than I do) and will marvel at this poetry-reciting, guitar-playing, genius of a solver, Simon Anthony, and be so glad you discovered him and this channel. (And of course I am probably just revealing how very non-brilliant and non-genius I actually am by saying all of that - but I am entirely right about this channel being one of the very best and most interesting places to hang your hat on the whole internet.) Kudos, Simon. I take my hat off to you - take a bow!

[@sudokuskunkworks]

I wonder how many solvers found the Easter Egg in Duality!!

[@disneian]

Great solve! Such intricate rules and thought for the puzzle! Some thoughts on the solve: 31:49 I think if you coloured the AB, r6c3 would be quite obviously can't be AB; 37:05 Instead using DE in r6c3 when you are unsure whether DE could be C or not, I think using "XYZWT" (yea I arranged WT last like mathematicians would use xyzzy first then go back to w and t) or "MNOPQ" would signal that they are a different set of digits and you they could still be overlapping with C

[@DarklordZagarna]

Wow, some incredible meta-logic involved here. The great puzzlemaster Ray Smullyan is smiling somewhere.

[@HunterJE]

1:04:40 I think you do know - the other three cage cells in row 2 already have 2 6s and 2 3s, so to keep everything ambiguous the remaining spot must be 14 to avoid creating a pair or triple

[@inediblenut]

I think the wording is accurate. It says any selection in one cell must lead to a valid solution, but that does not mean that there are only two valid solutions. There are several valid solutions, I believe, but each cell contains at least one solution (perhaps not unique) for each of the two possible values in that cell.

[@TheGreatAndMightyBob]

Thanks for posting a comment about this. I'm not sure I agree (but I may be wrong).I think I am getting tripped up on the phrase "lead to a" in the rules. In my mind, its not that putting a specific digit in a cell doesn't allow for a valid solution to exist, it is that it doesn't it doesnt lead you to a complete solution at all. I might just be silly though.

[@nekizalb]

I feel like Mark is just hunting for a puzzle that will force Simon to pencil mark as aggressively as he does.

[@jardozouille1677]

Really crazy, I loved it

[@thithildeprouv8310]

That genuine laugh at 38:30 cracks me up !

[@williamdehen1241]

It's rare that I am actually seeing logic and shouting at the screen, but this puzzle just hit my logic brain I guess. But I promise I was never cross with you Simon.

[@amberfrost7766]

fantastic puzzle and an even crazier solve !

[@RJ_Eckie]

A quick scan through the comments hasn’t given me someone else pointing this out, so I will: Secret of Schrödinger’s Cells: Each digit in a Schrödinger’s Cell must appear exactly twice - in Schrödinger’s Cells - in the row, column and box it is in. This could significantly speed up finding the Schrödinger’s Digits!

[@garmo1968]

I got as far as noticing the pair in row 4 col 1&2 as well as row9 col1&2 are the only places where there are odd quantum cells in the row, in the column and in the box, and that setting the deadly patterns there by color coding was likely the key to breaking into the puzzle... but had no clue beyond that into how such a task would be possible

[@ruthphelps1440]

Simon, you slayed this Balerion-sized dragon of a puzzle and I am thoroughly impressed!

[@ozargaman6148]

45:13 "ah Ah AHH! but I don't care, do I?" I'm saving this

[@Coyotek4]

This one stumped me ... it did not occur to me to use letters (I tried colors, which got far too troublesome). I watched about 50 minutes into the video and took it from there. Too tough for me ... but I'd love another crack at such a puzzle, someday. Just *insane*!

[@cyndisision]

Wow, this was a phenomenal puzzle!

[@victoriam6569]

It's a pity Simon ignored white dots in the 7th (and between 7th and 8th) box. It would've helped to rule out 8 easier. (Knowing that with 248 trio the only possible combinations left for consecutives are 56 and 67, and also that these white dots can't be identical. It needs only few more steps to rule 8 out) Simon's logic was incredibly hard. But it was fun to watch his approach and the way of thinking. My applauds. To the solver snd to the creator. Mind blowing. Bravo!

[@jonnybolton4659]

Such an interesting puzzle! I do agree that it's a little unclear regarding the resolutions at the end, it would kinda be good if the 59 pairs were resolved, which could easily have been done by placing a white dot on the 8 or 4 in Box 5

[@StormCrow42]

So much time missing the XY pair in the bottom of box 4 that would have taken the 7 out as an option quicker.

[@victoriam6569]

It's just another way of thinking! Bravo!