The Masterpiece 

Simon: "5 people have solved it, do have a go yourself in the link below" Me: "No, I don't think I will"

"Try it at the link below" Hahahahahaha nope

37 minutes in and still with an empty grid, Simon declares that "We always try to be new user friendly!"

5 of us attacked this puzzle as a group effort. It took us 66 minutes before one of us did the diabolical logic involved in working out where the 9s go. Staggering that you, working alone, got it so fast! As always, in awe of your ability, Simon.

Testers: “brutal, couldn’t solve it, gave up” Simon: “Let’s give it a go!” Such dedication.

Let me just take a moment to note how completely bonkers it is that CtC posts a minimum of two videos, recorded the same day, 365 DAYS A YEAR. They solve and post while on vacation! They solve and post during Christmas holidays! If they fail on a given puzzle on a given day, they do another one! It is, frankly, flabbergasting. If I accomplish one important thing in a week I consider it a productive week.

26:32 “I’ve done it… when I say I’ve done it, I’ve done the most minor thing, but I have done something.” Incredibly relatable but also kinda inspiring! On those days when you have little motivation or energy, even a little thing you do is still something.

other people watch a 90min football world cup finale, I watch this machine of a man solve a sudoku.

At 25:50, I got into an argument with Simon: Simon: "If it's got 3 9s in it, then the perimeter would sum to..." Me: "135." (since (36+9)*3=45*3=135) Simon: "27 and 3 lots of 36, which is 118, plus 27, which is one th... 145, isn't it?" Me: "No." Simon: "It's 145." Me: "No." Simon: "Yeah." Me: "No." Simon: "Yeah." Me: "No." Simon: "I'm going a bit crazy, but yeah, I think it's 145." Usually when I shout at the screen, the person doesn't respond. Occasionally, the person notices what I said, which is fun. But I've never had someone argue with me before.

What on Earth are you apologizing for? Noone watching your videos feels them to be a waste of time. We are all here for your amazing solves and this one was truly epic. In my opinion one of the finest solves you've ever done. What a puzzle and what a solve. Bravo! 👏 👏 👏

So impressed with Simon's ability to keep talking, be engaging and humorous, whilst being bereft of ideas, I love the logic path, it took me 4 hours, then watched the video to see if id missed an obvious step but no, just not in that league :), would love to see a youtube video from Nahileon on how on earth that was conceived

Even in ten times Simon's time, I could not have solved this complicated puzzle. So I just watched Simon solving it, which was exciting and amazing enough.

I love how Simon basically finds the most roundabout way to prove that 45 - 9 = 36 and it was extra amusing because I could see it coming a way away.

Oh boy... dear Simon, this wasn´t just a solve, it was a journey. And in the end, I too had a tear in my eye, just to see your elation, just... unforgettable. Love, Sheila.

Does anybody else out there really, really, really feel like they want to reach through their screen to hand Simon a calculator and a sheet of paper?

I know I'm going to sound like Simon here, but THIS PUZZLE is legitimately so *brilliant*, that it leaves me almost speechless. I honestly think this is better than (at least most of) Phistomophel's puzzles. Such a deviously difficult break-in, step after step, with each minor deduction there were a hundred more to make! But Nahileon held your hand through the whole ordeal and gave you just a glimpse of their brilliance. What a journey to be privileged enough to even watch this be solved. Thank you Simon and thank you Nahileon.

There's something so incomparably wholesome about Simon wanting to make the video simply to save the logic in the first half hour.

Q: Do you have any special powers? A: I can proof the Phistomefel Ring for you. I just loved Simon's emotion at the end. So touching. I'll never stop following this channel.

When Simon said that one of the rings must have no 9's I was convinced he was mistaken because the rules clearly state that the logic of the rings is dependent on the 9's. It even included extra clarification of the logic if one of the rings has a single 9, which would only be possible if there were 9's on all rings. Such a red herring!

Rules: 02:59 Let's Get Cracking: 06:44 Simon's time: 1h29m17s Puzzle Solved: 1:36:01 What about this video's Top Tier Simarkisms?! Phistomefel: 19x (09:17, 09:30, 19:32, 19:52, 20:08, 30:30, 31:02, 31:59, 32:31, 32:37, 34:07, 35:01, 36:59, 37:15, 37:27, 40:09, 41:22, 41:36, 1:13:48) The Secret: 5x (12:13, 12:16, 12:17, 12:20, 12:22) Three In the Corner: 2x (55:43, 1:01:37) Goodliffing: 1x (1:23:44) Knowledge Bomb: 1x (27:29) You Rotten Thing: 1x (48:50) And how about this video's Simarkisms?! Hang On: 17x (09:22, 09:22, 09:22, 11:46, 13:29, 20:55, 20:56, 31:13, 31:13, 31:13, 31:17, 53:00, 56:46, 56:48, 1:05:53, 1:30:09, 1:30:09) Ah: 15x (13:15, 22:09, 34:44, 34:45, 34:45, 1:04:48, 1:14:33, 1:20:47, 1:21:36, 1:24:01, 1:28:07, 1:29:35, 1:33:56, 1:35:21, 1:37:08) Obviously: 12x (10:50, 22:57, 26:53, 27:02, 31:47, 34:24, 39:45, 56:37, 1:05:20, 1:09:31, 1:16:39, 1:27:25) Sorry: 11x (07:56, 10:35, 54:21, 56:15, 1:24:19, 1:24:27, 1:29:23, 1:29:26, 1:29:26, 1:30:45, 1:36:09) By Sudoku: 6x (35:21, 1:01:52, 1:02:00, 1:24:01, 1:34:08, 1:35:51) Nonsense: 5x (20:24, 20:28, 28:07, 59:18, 1:26:57) Ridiculous: 5x (1:11:58, 1:12:00, 1:21:28, 1:36:31, 1:36:34) Surely: 5x (19:47, 21:43, 30:27, 30:30, 1:35:04) Proof: 5x (19:19, 19:26, 19:32, 37:07, 40:06) In Fact: 5x (03:17, 17:00, 19:47, 36:21, 1:17:30) Good Grief: 4x (03:40, 40:12, 1:10:51, 1:26:28) Lovely: 4x (06:32, 14:44, 1:08:22, 1:33:25) Beautiful: 3x (55:15, 1:09:05, 1:27:34) Brilliant: 3x (01:44, 1:11:52, 1:11:52) Corollary: 3x (31:17, 31:29, 1:16:56) Goodness: 2x (1:10:54, 1:36:12) Naked Single: 2x (1:21:46, 1:21:53) Pencil Mark/mark: 2x (28:06, 1:27:12) Unique: 2x (05:55, 06:13) What on Earth: 1x (32:06) Bother: 1x (1:04:41) Clever: 1x (1:21:21) Missing Something: 1x (1:13:13) Stuck: 1x (19:16) Incredible: 1x (05:52) Extraordinary: 1x (02:47) Going Mad: 1x (11:46) Take a Bow: 1x (1:37:16) Unbelievable: 1x (53:24) What Does This Mean?: 1x (41:16) Scrabble Tiles: 1x (38:11) Cake!: 1x (01:46) Most popular number(>9), digit and colour this video: Twenty Nine (36 mentions) Four (145 mentions) Green (21 mentions) Antithesis Battles: High (2) - Low (2) Even (15) - Odd (3) Outside (5) - Inside (0) Row (23) - Column (14) 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!

Never a waste of time to watch genius at work. Amazing work

This puzzle lives up to the video’s title-truly an amazing puzzle and an absolutely gripping solve!

Simon: "Do Give it A Go" Me: "I think I'll Sit this one out" 95 Minutes Later: Me: "Excellent Decision".

Brilliant setting and solving. I see a lot of people in the comments complaining about overcomplicating a step, but this is such a complex puzzle that I would argue any solution whatsoever is ridiculously impressive and an accomplishment that I would never attempt. Well done. A great discovery by Nahileon as well.

Absolutely mad. What a solve. Simon, you're amazing. Seeing you solve these is an absolute highlight of my days.

I mean this in *literally* the nicest way possible: after just under n hour of math babble, we have more math babble, an empty grid, and Simon saying he's got the solution. I love these videos, they're so entertaining to watch cause I'm sitting here trying to figure out how any of this works and he's just chugging and plugging away with a helluva lot of patience. I commend you sir for not getting bored or frustrated halfway through this.

The break in is insane. Looks utterly impossible. Of course I didn't expect an outer ring with no 9s and added the needed 9s with the 36... realised that's not it and then it flowed well. And just when I thought I had it in the bag I got to the thermo and that nearly broke me. I made so many mistakes there and had to rewind a ton... Mental (=fantastic) puzzle. So well crafted, I am in awe.

"I'm so sorry to waste your time like this"... If you just knew that watching your videos is the best part of our days...

It took me 2 weeks of staring at the screen day in and day out, but I finally solved it. This is just incredible. Nahileon, you are some kind of sudoku god

I love the complicated way Simon works out 8 × (1+2+3+4+5+6+7+8) ÷ 8 😆

As an adult with only basic Sudoku experience, and as a new viewer, watching you solve puzzles and explain the logic as you go is so fascinating. I know just by watching you that you love doing this, which makes the experience so.... Comforting. It makes me happy. Thanks Simon. 🙏💖👍

Please think of this one next time you feel moved to doubt how clever you are. A solve to be truly proud of. And of course, take a bow Nahileon.

Amazing puzzle and solve. Ironic that the big breakthrough at 26:30 contained a math error. "Three lots of 36, plus 3x9..." does not equal 145. Three lots of 36 = 108, not 118. Plus 27 equals 135. The logic that followed still works because the minimum of the outer ring is 146, which is more than both 135 and 145. Not a criticism...I couldn't even get that far. the logic to get to the math error was impressive, and I'm sure you would have caught it if it had mattered.

I was thrilled when I was able to solve this. Actually, I was thrilled when I solved each step! That said, I was able to type in a bunch of numbers in the grid (my equivalent of scratch paper) to add up and average each ring until I came to the number. I have no idea how Simon can hold all those numbers in his head WHILE doing arithmetic. On the thermo at the end, once I got 4 into two places, I looked what would happen from each of them in each direction, and kept running into 128 triples which clashed with a 128 nearby. That seemed easier than scanning the columns looking for clues. I think most of my other differences were mentioned in comments. Simon, you and I both deserve a giant piece of chocolate cake after this one! And maybe you should get two, since without you, I wouldn't have ever learned to solve well enough to tackle this puzzle.

Proud of myself for solving this one! And so happy I made the decision to give it a go. It's late now, but looking forward to watching Simon discover it tomorrow :D

I haven't done Sudoku in a long time and I can barely complete "easy" ones, but man, after YT randomly recommending this channel, I've watched about 3 hours (3 videos lol) and it's insane how mind bending and intricate these puzzles are.

77:37 for me. I have to admit I had one glance at the video though, as I had made a mistake and couldn’t find the way to fix it. In the end it was just one digit, but the few seconds in which I thought everything I had done so far was wrong were scary. Awesome break-in, I’m very happy I was able to do that part all by myself.

Magnificent. Your perseverance is incredible Simon. Thank you Nahileon for helping produce one of the great wonders of the internet.

I love how you say "how do we prove 9's" like I'm helping you when in reality I understand all the individual words but not the sentence you've made with them 🤣🤣🤣

I love how complicated he made proving there were no nines on the phistomefel ring 😂 Once he showed that the gap sums in the outer ring were at least 28, that means there are at least four cells between any 9 on the phistomefel ring, but there just aren’t enough for that and the four 9s

at 92 minutes, you discuss why one of the cells can't be 7 by a long explanation, but an easier way to see that can't be a 7 and the cross cell can't be 3 is that it would put an 8-1-2 across the top of the box, which would negate all options for box 6

Can you imagine getting the yellow box filled in, right when you said "please don't be any more hard steps" Simon, and then seeing there is a swordfish on 6's or something like that and then seeing that it goes into some triple nested swordfish nonsense. 96 minutes of madness indeed. The relief and jubilation in your voice at solving it was just wonderful to behold. Absolutely amazed.

I love learning the phistomefel ring theorem from you and it was worth watching the whole video. When you figured out the numbers 3-4-2 in the inner blue ring corners getting help from the 3 on the left it made me realize how cool the puzzle little hints were effective still to solve it. I have to rewatch this tbh to dissect your logic with the 9’s in the red boxes how they weren’t green.

Simon you are PURE therapy! What an absolute joy it is to journey alongside you whilst you solve these puzzles! Sincere thanks to you.

At 36 minutes, you took an extremely roundabout way to figure out it was impossible. A much simpler approach is: Given that you know there are 4 9s on each ring, the *very best* you can do is spacing them equidistant from each other. Any other spacing results in at least one gap that is either longer or shorter, so regardless of which your goal is, you're shooting for equidistant. Because of phistomefel as you said, the outer 9s are fixed, and since each gap is in a straight line, we know it sums to 28 (as you said). However, we can apply similar logic on the inner ring. Spaced equidistantly, every gap is 3 spaces. If (ignoring all sudoku rules) we placed a 9 in every single square, that still only gets us to 27, so even ignoring every other restriction, it is not possible to achieve gaps of 28 with single digit numbers in that ring with 4 9s in place. Therefore, it cannot be correct. (Genuinely amazed and impressed overall though. I can spot little things like that sometimes, but I guarantee you I couldn't solve this whole puzzle)

What an amazing ability to keep numbers in the head and run some astonishing mental maths!

Normally Simon does vastly better than I in solving because he quickly hones in on general truths while I muck about with specific cases. However, in this instance that surely led him astray in the early part of the solve, as he entertained abstract notions like the outer ring containing only two 9s. A few seconds trying that out would have quickly shown that you'd get an absurdly large sum which the remaining 9s packed into the inner rings couldn't possibly accommodate.

That is the single most brutal break-in I've ever seen. Well done cracking it!

I was not watching the channel for a year, and I am happy to see on my comaback how far the sudoku app used got with the multi-coloring and stuff. Now the only thing missing is to be able to put in big numbers with green or something so Simon doesn’t ever confuse a digit he actually found with one he wrote in as an example.

So much fun to watch along with you and Mark!

These were the best spent minutes I'll never will get back. I am so impressed with your solve. And I am so happy to get the opportunity to follow along with your train of thoughts. Hats off!

This is absolutely crazy and words are not enough to describe this puzzle. Congratulations for solving it. This video should get a million views because there is no greater madness to be found anywhere else.

Wow! This was such a fun solve-along, though I had to follow you closely through the initial logic. Big thanks to everyone involved.

I love that at 1:06:40 you work it out by maths, completely ignoring sudoku.

That was absolutely mind bending. I had to rewind the video a number of times just to follow what Simon was talking about. Well done!

I love when Simon starts clutching his head, that’s when you know you’re about to get your mind blown

So much fun with the chat replaying on the side, even though I missed at at the time :) Great solve, great puzzle, brilliant community - thanks everyone!

Most beautiful Sudoku I have ever seen. Great solve! I love your tenacity and how well you formulate the steps that you take during your solves.

Understood almost nothing after more than an hour but eventually managed to follow along. But I just enjoy watching someone who’s brilliant at their craft, do their thing

Usually Simon's videos are a nice, relaxing journey through beautiful logical deductions that I follow along and nod, but this one reminded me of walking in on a graduate quantum field theory lecture. 🤣

I would love to watch a video chronicling the creation of a puzzle like this. From inspiration to completion.

Love watching CTC! Thank you for your videos!

this solution was gorgeous! massive kudos to the person who created it and you for solving it so elegantly!

Truly amazing how these puzzles are created! Props to the creators!

YAY Simon!!! Congrats on getting the puzzle done for us. Thank you.

This is exactly the kind of puzzle that fits me. After understanding the rules everything became so smooth and beautiful. Thank you very much for featuring this amazing puzzle. And thanks to Nahileon for putting up the work and setting up the puzzle.

Took me all day to solve this with several multi-hour breaks. I alternated between making quick progress, making no progress, and breaking the puzzle. It was actually after I knew there were four 9s in the blue and grey rings, and I filled 9 digits in the Phistomefel corners that I stalled the longest. I'm happy I finished this puzzle at all, and very pleased to do it all in the same day (within 12 hours even). So much fun to watch Simon struggle, often finding more complicated alternate paths -- faster than my simpler logic!

When Simon is going through to prove that you couldn't have 3 9s in the outer ring with a gap value of 36, there was an easier way for me to visualize why. If you consider that to have 3 9s on the outer ring one of them MUST have one of those in the corner. Then the column it's in adds to 36, so the next 9 would have to be the first square after the corner, and the row is the same, leaving 13 spaces in between those 2 9s. The smallest you could make those 13 squares is 1 through 7 plus 1 through 6 (with 7 in the corner) which sums to 49

well in my first five minutes of trying this i convinced myself it can't be done at all, and in my next fifteen minutes i convinced myself even further it can't be done at all,

I’m very happy that Simon’s inability to calculate 3x36+3x9 didn’t actually change him figuring out that there couldn’t be only 3 9’s on the outer ring haha

This was insane. I’m so impressed at all the tools you used here.

Amazing puzzle. Wonderful solving. Thank you both for this 'MASTERPIECE.'

WOW ... just WOW. Simon, I love seeing you solving these next to impossible ones that takes you a long time where you really have to plead with your brain to com up with something, and I'd like to see more like these!

Simon, thank you for that video. The mental effort involved in solving that puzzle was enormous. I'm glad to say I followed most of the mathematical steps you took towards a solution. But I am sorry to say, I could never have found the solution path for myself. Thanks for making the journey possible for me.

My favourite video yet, well done Simon, that was seriously impressive!

I hope this isn't too off topic... I just want to say that Simon is a joy to watch... he has a beautiful mind, is quite articulate, and not at all vulgar (at least in these videos). I especially love to see and hear the expressions of astonishment when he figures out a bit of logic, and the praise he gives to the setters. Kudos upon kudos to you, sir.

It took 3 hours and 13 minutes with a few interruptions to solve this thing. It was quite fun. Thanks for continuing to share these unique puzzles with us.

Can’t believe I watched it all. But you had me gripped! Well done!

I finally finished it! It took me two days to figure it out, and I agree, it absolutely was brutal. But it was SO much fun. I had to take quite some notes until I figured out how the logic in this puzzle worked, so now I'll watch your video to learn how to do it faster next time I come across something like this again :)

The great thing about a live stream is that you don’t know how long it will take to solve, if at all. Amazing puzzle and solve 👏 👏

Stellar puzzle and an even better solve!

every time I witness you solve the impossible, I can't seem to describe it to others as anything but an absolute miracle of intellect. Well done, Simon. Can't wait for the next!

Absolute mindbending brilliance from Simon's brain. Emotional. I will go back to calling him an idiot tomorrow when he misses A REALLLY OBVIOUSS THINNGGG.

I literally shouted out loud when he started doing Sudoku with that 5 that he had placed as an example, that's just how invested into this I got

I am just stunned by how smart both Simon and puzzle are. That's amazing

So this was an amazing video. I tuned in to it about 8 minutes after it started, backed up to the beginning and (for me, very rare) watched it at 1.5x until I caught up. And then I watched it in the premiere format until I had to go at what turned out to be only about 15 minutes before the exciting conclusion. And then, because watching it as a premiere was actually a bit distracting because I watched chat more than the solve, I watched it again just now. Occasionally I paused in order to scroll through the chat at moments when I remembered something funny or interesting coming up in the chat. So here are my thoughts after all of that: Amazing. A.Mazing. Simon, you are absolutely brilliant. I was totally mesmerized as you worked out where the 9s had to be, what the totals between the 9s had to be, and all of the sublime logic surrounding that. And then, when you figured that stuff out, you quite sincerely said that "I almost feel like I should stop the video" in case you could not actually solve the puzzle, you did not want the beautiful logic to be lost. I was so amused but also totally get that. It would have been very sad indeed if we could not have had the chance to see how phenomenal your work was to that point. But thankfully you did not stop the video, you kept going, and so did the phenomenal logic. I mean, I simply do not believe what I saw - and I watched it twice. Then, when you had solved it ... well, video can mislead, and we read into what we see what we imagine ourselves to feel ... but it looked to me as if you were truly moved and overwhelmed to have solved that puzzle. And indeed you totally should be - what a puzzle and what a creation from Nahileon. Totally unbelievable, really, that it could function as a sudoku. I would love to know what the intended logical path was; maybe there is a comment from them below this one, I have not taken the time to read other comments yet. And you had put so much time into it, and as we have had the chance to learn through various ways that you and Mark do abandon videos because you cannot solve the puzzle from time to time, there you were, at the end of an impossible task, with a correct solution ... it must have been an amazing rush to have completed that. A few other observations: I absolutely laughed out loud at the vehemence of your "You rotten, Rotten, ROTTEN thing!" wow, three rottens! And "Holy moly moly moly moly ..." Totally funny. I know, you were not laughing at the moment, but you made me laugh for sure. And one thing that I particularly found entertaining in the chat was when you were near the end, and your hair was a bit mussed up (from your reaching over your head to, evidently, tug on the opposite ear), Mark asked "Does the wig finally fall off at the end?" I totally laughed at that. I am thankful that you did not lose your wig nor your religion, and that you were successful in solving the puzzle. OK, this may be a record long comment, but it was a very special experience. You asked whether we wanted to see more videos released as premieres. "For special puzzles" someone suggested, and I would say, yes, probably that is how I would feel, too. I do feel as if the chat was extremely fun, and it was very impressive the names/handles that I recognize speaking up in the chat, I mean, the other luminaries in the sudoku setting world, mainly. But the chat goes so fast, and it is so tempting to watch the chat rather than the solve, that I think that I would prefer that a premiere be very, very occasional. It was especially fun, though, that both you and Mark were involved in the chat - that definitely added to the fun. SO IN CONCLUSION: Thank you so much for this video, for the chat experience, for Mark being there, too, for all of the great things that you do on and for this channel. I am entirely sincere that these videos are highlights for me each day.

I tried this puzzle thinking every outer circle needs 9s, concluded it was impossible and almost gave up. I should definitely pay more attention to the details of the rules in the future... Thanks for the puzzle and the solving!!!

I can`t belive a watched it from start to finish with the same thrill you had solving it. thumbs up to you Sir.

The given 3 and 5 are such elegant clues. There are clear implications for what can and cannot go on the blue ring and its corners, or rather what can and cannot be left off. The logic required for the break-in was much too hellacious for me, but I greatly enjoyed following along with Simon's brilliant solve.

Simon, that was an amazing solve of an amazing sudoku. After seeing your final reaction, I was similarly awe-struck that the rings could accommodate 9s and that the other digits were so constrained that just 3 givens and that odd thermo were enough to break all symmetry and determine a unique solution.

Simon you looked frazzled after solving this puzzle. Brilliant solve though.

Took me nearly 70 minutes. I think the beauty of the puzzle lies in the inner thermometer, which seems subtle at first glance but of great beauty with proper logic direction.

This is amazing. Really really amazing. Congratulations Simon and crazy kudos to Nahileon.

I've never seen a person so thrilled to have digits in the grid. Beautiful

Took the puzzle, stopped the video, solved it over several days, came back. 1st step: Must be no 9's in yellow ring: check. 2nd step: Sum between 9's must be 29: check. I'm pretty sure we did the exact same math, but you somehow did it in a fraction of the time and without writing anything down. By this point I also had that the corners had to be either 8875 or 8776. 1:24:44: mine looked exactly like yours at this point. Except for the 3 middle orange cells on the left, which should not have 6's in them (the 6 has to be up above). My solution ultimately involved a lot of math and long lists of possibilities for various bits, and then logically eliminating possibilities. You somehow do all of that in shorthand in your head. I have more of a disadvantage these days because my disability means chronic fatigue + brain fog + pain + pain meds which add to the drowsiness... But still. I was never quick. Good at getting there, in the end, but never terribly quick. :) You are good AND quick.

You know how it is said that it is a pleasure to watch someone who is good at a task accomplishing it? This is one of those occasions. Absolutely mindblowing.

That is truly one of the best things I have ever seen. You are amazing!

Beautiful solve really enjoyed that one, thanks!

First time I watched live and what a puzzle!

Awesome video. Thank you for pushing on!