PhD-Level Sudoku

[@shiftcyclicity]

Thank you so much for the feature, Simon. You did the puzzle exactly the intended way, and I'm glad you were able to realize at the end how the 21 cage comes into picture! Just to break your brain a little, the puzzle doesn't work if you had a 20 cage instead of the 21. It breaks after an ~75 step long chain lol. The idea was to create a puzzle with 9 cages, where each cage gives you information about exactly 1 digit, and then solve from there. Given the symmetric construction, I did have to add one white dot but as you can see, all it does is resolve box 5 completely. Everything else is pretty much already done. I'm sure it is possible to get a unique solution with only 9 killer cages or maybe even 8 (no restriction on size of the cage, and no other information in the grid)... if anyone knows the answer or has an example then do send it my way!

[@rubens_cube]

Hello Jeet, A while back there was this video that appeared on Cracking the Cryptic. It is a killer Sudoku with only 8 small cages and no other rules. Hope you find it interesting. kzbin.info/www/bejne/m5vLpYyPq7qma68

[@RMGiroux]

@rubenscube - I'd forgotten that one, fun rewatch!

[@rubens_cube]

@@RMGiroux It is one of my favorite videos from CtC. I really like these puzzles that push the limits of minimality. I still wonder whether it is possible to have a 17 cell Killer Sudoku or not

[@shiftcyclicity]

@@rubens_cube lol duh of course Philip Newman has thought about it. And yeah, I have no clue how I forgot about white room. One of the best (if not the best) killer sudokus. I think in my mind, I imagined it had 9+ cages.

[@SSGranor]

@@shiftcyclicity It's also possible with only large cages. My puzzle Deadly Bins is unique with 9 seven-cell cages and nothing else (Not, mind you, that it's anywhere near as elegant as either this puzzle or White Room). And, Reson showed that, with 8 eight-cell cages you can at least get down to just a single four-cell deadly pattern.

[@aidarosullivan5269]

I love how smart Simon is. His carefree attitude towards coloring, on the other hand...

[@stevieinselby]

And scanning!

[@DontMockMySmock]

Simon at the end: "let's tidy up the colors" also simon: leaves a green 8 in the grid, also leaves one lonely 3 colored blue

[@topilinkala1594]

It was clear that Simon did not see the cages from the colours. The solve would have been speedier if he'd removed the colour when he finds what number is behind it. I do not understand why doesn't Simon see that colours are placesholders when you do not know what the numbers are and the minute you know you clear the colours.

[@DontMockMySmock]

@@topilinkala1594 yeah that drives me up the wall too

[@Acidren]

"That square is either a 1 or an orange" has to be my favorite quote from this solve, great video!

[@David_K_Booth]

Glad to see that you're back home, Simon. Must be a relief for you and the family.

[@longwaytotipperary]

Ditto!!!

[@MattOGormanSmith]

One word. Photovoltaics!

[@longwaytotipperary]

@@MattOGormanSmith New vocabulary word! 😃

[@Anne_Mahoney]

Yes, welcome home.

[@tarbosh917]

My favorite part of Simon's puzzles, and I've said it before, is when he finds backdoor logic to conclude something that was a bit more obvious than needed and likely not intended by the setter. Sometimes it involves him not noticing an obvious number and then goes around about way of filling it in 20 minutes later. This time it starts when he's wondering if the 89 corners can be the same, and the answer is pretty obviously no since it would rule that number out of each of the 42 cages. They'd have to be different. It's like an expert's curse where he's giving the puzzle the respect of being complex considering the simple use of large cages and a single kropki dot, but in doing so his focus is on more advanced deductions and the simpler ones are in a blind spot @27:00 he catches it though!

[@watzimagiga]

He also overcomplicates the "corner being 1/2 logic". You can just say that all 7 cells in thr 42 cage see (which are 3-9) see the corner cell. So it can only be a 1 or 2.

[@rymag1730]

Noticed this too, but it made me feel as if I'm the one missing something. If it's that easy to spot surely there is a reason where my logic is wrong as it can't possibly be Simon missing it. Guess he can :P

[@tamarockstar45]

Or when he could've place a 3 in box 5 at 52:40 by sudoku and doesn't see it until 59:00. I'm staring at it wondering when he's going to see it. But I wouldn't even know how to start this puzzle.

[@tottivirtanen8184]

If the 89 corners where the same at the beginning there would still be one place in the 42 cages for that number

[@miff227]

@@tottivirtanen8184 yep, the logic there is seeing that putting an 8 or 9 in R2C8 or R8C2 immediately breaks the 40 cages, so R1C1 and R9C9 have to be different in order to not force the problem.

[@emilywilliams3237]

I love the long videos. I also love the short ones. So it is great that there is such variety on this channel. Whenever you apologize for doing a long video, especially on a Friday night, I want to reply, "Simon, anyone who is watching any kind of video about sudoku on a Friday night is probably just as happy for it to be a long video." As for me, I usually watch them the next day or so no matter the length. The advantages of being retired. Thanks as always for an interesting video, and thanks to Jeet Sampat for a great puzzle!

[@inspiringsand123]

Rules: 02:18 Let's Get Cracking: 03:26 Simon's time: 1h6m54s Puzzle Solved: 1:10:20 What about this video's Top Tier Simarkisms?! The Secret: 6x (03:56, 03:58, 04:04, 04:37, 05:35, 05:35) Bobbins: 1x (52:12) Goodliffing: 1x (10:29) And how about this video's Simarkisms?! Ah: 24x (11:54, 12:04, 13:27, 15:35, 16:17, 16:18, 18:15, 22:48, 24:39, 28:09, 32:29, 38:46, 42:47, 48:51, 49:03, 50:37, 51:48, 55:45, 56:31, 56:33, 58:39, 59:06, 59:46, 1:03:29) By Sudoku: 12x (16:35, 16:56, 23:30, 24:56, 33:40, 37:54, 40:24, 51:25, 54:05, 1:00:03, 1:08:27, 1:08:43) Good Grief: 11x (25:14, 33:56, 35:22, 35:39, 37:24, 40:12, 45:33, 57:28, 1:01:37, 1:07:23, 1:09:54) The Answer is: 11x (16:31, 18:32, 20:02, 23:25, 24:44, 30:32, 34:22, 35:26, 43:42, 56:45, 1:00:21) Sorry: 9x (19:59, 20:53, 26:33, 35:39, 43:03, 50:17, 1:07:33, 1:10:23, 1:10:23) Beautiful: 6x (12:04, 20:22, 44:38, 45:29, 59:49, 1:11:05) Clever: 5x (16:25, 44:33, 44:33, 44:36, 45:33) In Fact: 4x (03:44, 08:56, 46:23, 1:03:40) Obviously: 4x (04:43, 37:46, 45:48, 47:19) Wow: 4x (23:44, 47:46, 47:46, 1:12:44) What Does This Mean?: 4x (08:28, 26:24, 27:36, 53:39) Fascinating: 3x (24:14, 1:10:36, 1:12:44) Goodness: 2x (10:27, 1:08:53) Lovely: 2x (16:52, 24:39) Shouting: 2x (07:50, 07:50) Approachable: 2x (01:57, 02:00) Hang On: 2x (18:15, 19:27) Whoopsie: 2x (08:17, 50:27) Fabulous: 2x (1:07:20, 1:07:22) Apologies: 1x (19:33) Nonsense: 1x (18:15) Horrible Feeling: 1x (1:11:17) Brilliant: 1x (00:55) Break the Puzzle: 1x (11:25) Extraordinary: 1x (1:11:11) Deadly Pattern: 1x (1:08:16) Come on Simon: 1x (48:10) Surely: 1x (50:09) I've Got It!: 1x (24:39) We Can Do Better Than That: 1x (1:04:54) Progress: 1x (31:17) Most popular number(>9), digit and colour this video: Forty (49 mentions) One (107 mentions) Yellow (91 mentions) Antithesis Battles: High (11) - Low (4) Even (5) - Odd (0) White (6) - Black (1) 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!

[@highpath4776]

These Are The Decisions That Really Vex Me (take all or any word/s from that !) 17.48

[@sampekula9642]

"Have A Think" should be added to this!

[@Oldy87]

"That square is either a 1 or an orange." Ah yes, I think we've all thought that during a game of Sudoku.

[@SnowTheJamMan]

Glad to see more of Jeet's puzzles getting featured, he's one of my favorite setters, he draws you in visually with some really neat looking grids, and makes you stay for fantastic logic. I haven't solved this one myself, so gonna be a great watch.

[@shiftcyclicity]

[@TheSonicPerson]

yes, Jeet makes great puzzles

[@longwaytotipperary]

This is one of the most positive channels on earth! So much respect, appreciation and admiration for both setters and solvers. Almost totally kind and considerate responses from everyone! I love this channel and am so thankful that Simon and Mark birthed it and continue to sustain it!

[@donatello_8691]

Perfectly solved!! The only downfall is forgetting to make the 8 in cage 5 a purple.

[@JS...]

That green 8 in box 5 at the end ... Although green is much much better colour than pink.

[@arekfu1980]

I will never get tired of Simon explaining the ˢᵉᶜʳᵉᵗ

[@_Matchu]

I wish there were so-called "anti pencil marks" so instead of writing "1234589" in blue, you could just write "67" in red

[@stuartgoesbirding8999]

45 minutes for me. I don't think I've ever beaten Simon's time by 20 minutes before, the comfort of being home again must have becalmed his brain!

[@VincentNick820]

loved the "terrible at sudoku" at 59:55 this puzzle would take me weeks to even start, brilliant puzzle though

[@therocknrollmillennial535]

1:02:34 for me, which might be the longest I've ever spent on a sudoku, which is far more a testament to the creator than it is to my own will. Thank you, Jeet Sampat, for the brilliant puzzle. And thank you, Simon, for the beautiful solution video to help me get through it!

[@jeffreybrookner9251]

I’ve noticed a subtle difference between an approach I take to a particular situation and the approach that both Mark and Simon take. I’m wondering whether (a) it is a coincidence, or (b) Mark’s and Simon’s approach is somehow superior. The situation arises when a pair is directly resolved by a number in a different box. For example, suppose there is a 79 pair in R1C1 and R1C2, and a 7 in R8C1. When I see this, my first thought is that R1C1 can no longer be a 7, so it must be a 9. I type that 9 in, then type a 7 into R1C2. For both Mark and Simon, the process is slightly different. They observe that the 7 can no longer be in R1C1, forcing the 7 into R1C2. They type that 7 in, then type a 9 into R1C1. I suppose the difference might be that my approach focusses on which numbers might go in a particular square, whereas Mark’s and Simon’s approach focusses on which squares a particular number might go in. Obviously, both approaches are equally valid. But I'm wondering whether their way of thinking about Sudoku has advantages in this or some other context.

[@pelahnar4]

My process tends to align more with yours, but I generally go with the "not" logic. Like, in your example, rather than seeing that R1C1 couldn't be a seven and so typing in a nine, I remove seven as an option, leaving the little 9 by itself. I don't make it a big nine until I've looked at all the consequences of the nine.

[@Coyotek4]

It took me *ninety minutes* ... to get a SINGLE DIGIT! From there I was able to finish, in just under two hours (1:53:06). Suffice to say, I had patience today. Incredible puzzle!

[@pixllo]

That's the spirit, never give up. The timer is just a metric to compare and maybe compete, in a way taking more time and having the patience might be more commendable.

[@viri6839]

You got there in the end, that's all that matters!

[@ChiefFalque]

@@pixllo I second this.

[@lokedemus7184]

20:45 Or you could just realize it would remove 8 or 9 from the 42 cages

[@lesyriad]

Came to say the same thing lol

[@cyberrb25]

20:33 Far easier. Suppose it's an 8. Where do you put the 8 in the 42 7-cell cages that, by definition, have to have an 8?

[@pedrobluis]

One easier way to see that the 89s where different is to realise that both have to appear in both 42 cages.

[@gregind01]

Welcome back home Simon. 😊 At 1:07:10 it is easier to determine the 8 in r4c5 using the 167 triple that you already had in the row instead of calculating that you had a 17 pair in row 4 eliminating 1 and orange possibilities from r4c5.

[@Trizzak]

1:09:26 "so that everyone is happy with the colouring" ... **eye twitch from the green 8 in box 5**

[@CuratedPile]

That last 5 had me yelling at the screen for a long time. It could have been had by looking at the 67 pair in the 40 cage. Great puzzle, and great solve video. I played leap frog while watching the video, managed to finish it out before watching to the end. Wasn't timing.

[@Gonzalo_Garcia_]

55:02 for me. Wow what a puzzle. The beginning is already great, but the key step where everything gets solved based on one single clue is absolutely fantastic. Awesome puzzle.

[@JTTomlinson]

“That’s far too clever for me” - guy for whom it was clearly not too clever

[@stevendavid5370]

Glad to hear you're back home with power. Hats off to you for giving us puzzles daily while you were dealing with a power outage. Thank you so much. Well done on this puzzle!

[@ericpraline1302]

Thanks, there was some beautiful logic in this, particularly the 21 cage, and despite being mildly intimidated by the video length I didn't find it horrendously complicated.

[@th.nd.r]

Don’t beat yourself up Simon, this puzzle seems really hard! Awesome setting and solving, love the ideas here.

[@sugarfrosted2005]

Green 8 is a friend.

[@julieannmyers8714]

Green 8 is a frenemy!

[@leojs5673]

Welcome back home Simon! Glad to hear you’re feeling more comfy 😊

[@bobbis.172]

45:37 "and now we might have a start" 🤣I just love how incredibly intelligent and creative (and determined) everyone involved with this channel are-- the setters, Simon, and Mark. I learn a lot and really enjoy watching these videos.

[@jmbverlag]

Yay, over an hour :)

[@miss-sagemoon]

I love having these videos playing while I do something else, since you occasionally get stuff like "yellow is not green by definition"

[@TurquoizeGoldscraper]

When Simon was wondering where 8 would go in the 40 cages and did a bunch of logic to prove that r1c1 and r9c9 had to be different, I looked at the 42 cages and realized that making both of those the same digit meant there was no place to put it in the 42 cages. And then 10 minutes later Simon sees it and realizes what he did was for naught.

[@stephenjames2951]

You can tell it’s a tough puzzle when Simon puts his finger on his chin.

[@G.Aaron.Fisher]

I can't believe how hard this was for me. It took a touch over 2 hours. I'm thinking that there must have been a really elegant piece of logic that I brute forced my way around.

[@Sakamori14]

Congrats, Jeet Sampat, probably this was the most confusing coloring pattern Simon had to come up with by the end, hats off.

[@shiftcyclicity]

🙃

[@gauravmitra150]

I tried this puzzle, and early on I found out that the four cells from the 19 and 28 cages sticking out of boxes one and nine have to be a quadruple adding up to 10 and 11, then I ran out of ideas. And Simon, I think you should not apologize for entertaining us for any time period. Even my 6 months old Golden Retriever puppy watches you solve Sudokus (will upload a short video of it soon).

[@bradleyreed8876]

Excellent puzzle and great solve!

[@badsyntax173]

55:48 Simon talks about not finding clues with his cursor on a naked single 😂

[@pelahnar4]

He's gotten this comment often enough that I've seen a couple videos where he used it when stuck and it's got him unstuck at least once.

[@badsyntax173]

He found it just a few minutes later but it's pretty funny

[@michaelhoffman2011]

.... so it took me a while... but my browser crashed in the middle.. so it took me -57 minutes... go me.. very hard puzzle but pretty stoked i solved it... looking back over the video Simon did the same solution ... just 3 - 4 times quicker haha.

[@Soumein]

Hey Mark, Simon, and fellow Cra... uhhh.... Solvers!... Didn't watch the puzzle yet, but I'm here to say this channel taught me to watch out for uniqueness, today's newspaper used that, and I was able to solve it! Not on the actual paper, had to use the computer to notate easily, but hey! Thanks for knowledge bombs!

[@hedleybrowning5448]

Congrats for being back home!

[@skr6477]

this was great solve, even struggling is fair by that hard, minimal progress. had funtime watching. all the best 👍

[@davidrattner9]

Congrats Simon and welcome back home sweet home!!!

[@darreljones8645]

I realized, before Simon did, that the digits on the white dot could not be a 1-2 pair. They had to be 5-6 or 7-8, because there was no other way to distinguish the 6's from the 7's.

[@patrickdematosribeiro1845]

I noticed this as well. However, Simon refuses to use uniqueness so he wouldn't have used it anyway until he was able to find another proof.

[@darreljones8645]

@@patrickdematosribeiro1845 There's nothing wrong with Simon's approach. I just realized his instinct, that it would be a 1-2 pair, was likely wrong.

[@goonybl]

I love you Simon for making my day at the end of this puzzle thank you for making me laugh

[@jacobschwartz6379]

Not that it would have expedited the solve, but the 5 in box 8 could have been placed when you discovered that there was a 67 pair in the 40 cage in box 7. I was screaming at my screen when you were coloring the 6s and 7s and didn't see that the 5 could have been placed. lol Fantastic puzzle and solve nonetheless!

[@bobponce8885]

I found another way to start this puzzle is to look at the blocks of 42 and pencil in 9-3 in descending order and work with that information at the start. With two 42 blocks, it's a good headstart.

[@shteevuk]

Love this puzzle, although resolving the colors took me the best part of a day!! Simon, as usual, came up with a much more elegant way of resolving them than I did :) The method I used was actually a trick I don't think I've seen before, I hope I can fit it into a puzzle some time :)

[@puritan745]

Simon solving ALL the impossible sudoku's while saying he is terrible at Sudoku has me in RAOFL!

[@bristolrovers27]

Excellent setting and a nice solve

[@andrewnelson2525]

A bit of logic Simon did not use: Box nine has 89 in the corner, so then using maths and the Secret the four digits out of the box in the 19 cage and 28 cage must sum to ten or eleven. Furthermore none of those four digits can be the same or that digit has nowhere to go in Box nine, so those four digits are 1234 or 1235 and all different. This was not essential but helped me in placing the 12 cells around the grid.

[@DucciVinci]

The moment you exclude that 21-cage to be 579, you actually know the hypothesis of 1/2 on the dot has to be false. Every cage in the entire puzzle either has both 6 and 7 in it or neither of them. The dot is the only possible way to disambiguate.

[@igoretski]

Very nice technique with the colours. I wonder if I could use it, when I'm investigating two cage-options in a daily killer sudoku.

[@MattOGormanSmith]

5 minutes in, NEED MOAR COLOURS!!!!11¬

[@MyriamTT]

This is an amazing puzzle !!!

[@NeilCrabbe]

1 hour in the 'just terrible at sudoku' made me chuckle.

[@groovinhooves]

38:13 - Simply Not Green: one of my favorite Manchester bands.

[@MyriamTT]

1:00:35 Use the cage, Simon

[@solanumlycopersicum5687]

I normally refrain from commenting on videos that are several months old but since I just spent 7.5h (over the course of 2 days) on this sudoku I kinda feel like I have to... unfortunately I haven't been able to do this on my own, but after several attempts that had all thrown me for a loop at the same stage I caved in and watched part of the video. Turns out I took a wrong turn right at the beginning, falsely ruling out 6/7 from R2C2 and R8C8. Twice. And then in my further attempts I assumed my deduction had to be correct so I skipped ahead and started with a mistake already in the grid. Silly me. But other than that I did surprisingly well I think. The epiphany Simon has about the 21cage seeing most of the 40 cage and therefore having to be 489 evaded me, but since this is also the place where my earlier attempts all broke down I'd like to think I would have gotten there if not for the 6/7 mistake earlier on. This is also the point when I stopped the video and went back to solving on my own. This time it worked, so thank you Simon for lending a hand and helping me (a mere mortal who is quite new to the world of variant sudoku) explore this extraordinary puzzle! Fun fact: I watched so many of your videos lately that my head wanted to think about digits and colors in english. There was also quite a lot of 'bobbins' going on in there :D (Weird sperling mistakes are curtesy of my phone trying to correct everything to german words, weird phrasing and tenses are all my own ;-) )

[@jonhansen9622]

Great solve, Simon! But what was your guess on how long it would take you to solve?

[@dalekloss4682]

did Simon mis-color r4c5?

[@julieannmyers8714]

Yes!!! 🤣😳

[@Hitobat]

Yes, I felt it should have been green+grey for most of the puzzle. And then purple at the end...

[@barrydavies2977]

I love it when Simon says things like, "all the information is in the bottom. I think I aught to concentrate there" and then ignores it and looks at the top, where it's empty. 🙄🤣🤣🤣

[@r3ckl3ss66]

Pencil Mark/Rainbow Simon

[@solfeinberg437]

I like the argument that's developing around whether the NW and SE corner 89 values can be the same. However, I think there's a simpler resolution. Just look at the NE 42 cage. It has to contain an 8 and a 9, right? Well if the two are the same, 8's say, then the 42 cage can't contain an 8, and the puzzle's broken. Ergo the corners can't be the same!

[@jurjenvanderhoek316]

If r2c8 cannot appear in the 40-cage (which it indeed cannot), then it must 3 or 4, since both 2 7-digit combinations that add up to 40 contain 5,6,7,8 and 9. And since 1 and 2 are r1c9 or the 40-cage, we are left with 3 and 4. It is really handy to use a triangular sum-table.

[@ApesAmongUs]

34:43 Hmmm. I bet not. If that's a 12, then the kropka doesn't disambiguate anything. More likely to my mind would be knowing the green is elsewhere and the yellow in the center, then the yellow couldn't be 1.

[@danielwcrompton]

I saw that the 28 and 19 cages summed to 47, so the 4 outer cage squares needed to sum to 2 more than the corner square, 89, and could only be low or middle digits. I deducted that it meant that the outer cells of that cage must appear in the other cage, and visa versa. I wasn't able to complete the puzzle on my own 😔 Thanks for the great entertainment 🥂

[@ryaneakins7269]

Luke’s team is getting confused. “Red Leader standing by.” “Red, uh, 8 or 9 standing by.”

[@stephenmccarthy1795]

Love the green 8.

[@leotuxidas]

There's 1 frame at the start of another sudoku, Fancy Vase by Qinlux.

[@OnTheEdgex23]

I liked this puzzle. I feel so clever, I found the 1 in the 2nd row 3rd columns a while before you did, I was nearly shoukdting at the screen

[@isakenstrom3375]

Great solve Simon, as always!! I was just so hoping that you would find the 3 in box five at the 52:35 when you found the other 3s in order to make use of the white dot constraint! Happy to hear your house is warm again too! Cheers from Sweden :D

[@mrslilmama1]

don't apologize, i love the long video's.

[@longwaytotipperary]

ditto!

[@George4943]

@21:18 "How do we take this forward?" I'm not sure but the puzzle is symmetric. The only non-symmetry is the 21 cage and white dot. They must be used to break the symmetry. Not sure if looking there at this moment works, yet, but it is a place to look.

[@laurv8370]

at 21:00 - funny how you use 6 colors, when 2 would be enough, i.e. same two colors that you used to color 12 could be used to color 34, and the same to color 89, it would be even more clear what pairs with what (sorry for my minimalist thinking :P) (edit: hint: when you don't know what to do, try tidying up the pencil marks, hehe :P, disclaimer: I did not solve the puzzle and I don't know if I would have been able to, but kibitzing is way easier...) (edit 2: cmon man, let's make an enterprise, you break them and we finish them, I was screaming all the way to that green box in the middle than ended up a green 8 :P)

[@Vanderlism]

1:03:15 Simon: That 4 doesn’t deserve to be orange Blue 3 in top right: 👀

[@Zalaniar]

That poor 8 in the middle, it sat there green for so long when it should have been pink.

[@alienrenders]

37:03 for me. Nice puzzle. I did a lot of colouring. Not sure if it's the right way, but it did the trick :)

[@James_-_-_]

8 coloured green in middle box??

[@ltechdpen]

You were killing me on the 5’s with box 8 lol but I’m just a spectator it’s easy for me not to lose track and worry about regaining where I was elsewhere in the puzzle. Mostly because you keep going and you’re better than I am at this lol.

[@MrElvisNilsson]

After spending over 2h on the puzzle, I had to go back to your video and watch it until that brutal 498... man that was hard to find ^^;

[@Beamer1969]

Cleaning up the colors at the end stops you from seeing the witness marks of the confusion in the middle of the solve.

[@phuybrechts6875]

5in box 8 and 1 in box 5 is placebel on min. 55. Simon 😚

[@LithmusEarth]

6 minutes in, another way I might have explained it is that that top right cell sees every single cell in that 42 cage, therefore it has to be one of the two digits that aren't in the cage, a 1 or a 2. you are right and you can use information about the 40 cage to do more. 24 minutes in, You can do the splash red and splash purple between the 89 pencil markings if you really want to in the snake cages in box 1/9. 26.5 Minutes in, Okay Okay hear me out, I am looking at Box 6. the Green 12 cannot be in column 9, it cannot repeat in the 19 cage or the 40 cage so it's not in column 8. Therefore it's in Column 7 with Yellow. Which means.... It's placeable In the 40 cage up top in Column 8. I did it. Wow Do I rarely have that good of insight. (pats back). 35 minutes in, I also assumed once you worked out the 1 and 2s in the corner and the 8s and 9s maybe like 10 ish minutes in I was also like it's probably a 1 2 pair in the center. 35.5 Minutes only 9 minutes late, do not feel bad, Simon, you are an expert. 41 Minutes in, gray flash your green in the center box, also remove the 1 and 2 from the 19 cage in box 9, just seeing some clean up stuff that has been sitting. 42 minutes in, I also thought of set very earlier of the outer two rows/columns, but I didn't think it would do enough. 44 Minutes in that's pretty good, I wonder how much earlier that could have been spotted. 50 Minutes in, yep you solved the 19 cage in the upper left if you haven't seen it yet, Since 4 can't be in it, it's 1,2,3,5,8. So all the digits are even placeable too. Also Column 2's 4 and 8 and 9 should have actually broke that far sooner. 57 minutes in if you use your colors to finish your pencil marking you can pretty much just remove all the coloring at this point, it has served it's purpose and it was glorious. 59 minutes in I didn't expect that 3 in the center box, but if that's that, then I can place the 5, it's in the lower right, because it had to be in column 6. 1 Hour 6 Minutes in, Okay In Row 4, 9 is only placable in column 8.... which propagates enough 8s and 9s to place 8 in the that white dot, there you go. Boom. weird... as usual you managed to find the answer in a different direction, it's crazy how often this happens in your puzzles, you always come at it at a different angle, to the point I'm surprised whenever you actually come at something the way I saw it.

[@jaeusa160]

Maybe I'm mistaken but early on around 15min, once you'd proven the middle cells of each corner box couldn't be 1 2 8 or 9, doesn't that make all 4 corners unique? Each opposing corner covers the entirety of the 28 and 42 cages, which must respectively contain 1+2 and 8+9. If any corner matches, you've broken the adjacent cages by locking a necessary digit outside of them. I think I'm right and that this was intended. :)

[@pixllo]

Did it in 67 minutes, but I used some convoluted logic I don't believe I could replicate. ( i could though, have expained it in layman terms on the spot) Simon's solve will surely be more elegant, watching the vid now.

[@matthewdodd1262]

5:40 Again with Simon making the most complicated reasons for simple deductions. r1c9 is a (1,2) because r1c9 can not share a digit with r1c6 or r4c9. So both go into the 3 squares of the 40 cage in box 3, leaving 1 and 2 to fill the missing square in the 40 cage and r1c9. Isn't hard.

[@ec97123]

I enjoy watching your videos thanks man

[@maelwys5]

was wondering how long he would keep putting the purple in box 2 wrong (cause of the double fill in the 40 cage...) thankfully the 3rd time is the charm!

[@johnnyshortfor]

I want a bowling alley carpet patterned like Simon’s color-coding of this sudoku.

[@TheFreeBro]

You should try playing squabble royale. It’s a website where you compete against other people to solve wordles. I’d love to see how you two are as competitors

[@markscottuk]

You need to update your sudoku pad slide :) it’s been available on windows now for a while.

[@Nekromant05]

After you had resolved the three green cells in Rows 7-9, c8r3 must be a green cell imediatly because it is the only place in c8 where you can have a green cell. It can not go in the 19 cage because that already has one and if it goes in r4 or r5 that would rule it out of box 3.

[@stock.5iveO]

1:06:12 --- "That square is either a 1 or and Orange" -- hahahaha

[@Coyotek4]

I took a roundabout way to get to the end ... . . . ... I used SET and the cage totals, along with some knowledge of the given cages, to prove that the digits in the even-numbered boxes that are also in the Phistomefel ring, combined with the center cells in boxes 1, 3, 7, and 9, contained a single 3, a single 5, and two of every other digit. I was also able to conclude the same, swapping out the 'center cells' with {r1c5, r5c1, r5c9, r9c5}, concluding that those sets of 4 cells were identical. Eventually, I got my first digit: the '3' in box 9. And from there, I made steady (if slow) progress and eventually made it to the end.

[@neosmile8903]

45 minutes into the video: ahh finally the first digit found (to be honest i would probably not have found it in 3 lifetimes)