The Sudoku That Broke The World's Best Solvers

Today we try the puzzle that cut a world-class sudoku field to ribbons back in the 2017 World Sudoku Grand Prix final. It's by Arvid Baars and you can play it here:
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Rules:
Normal sudoku rules apply. ALL horizontally and vertically neighbouring digits with the sum 10 are marked with X; ALL horizontally and vertically neighbouring digits with the sum 5 are marked with V.
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▶ABOUT US◀
Hi! We're Simon Anthony and Mark Goodliffe, two of the UK's most enthusiastic puzzle solvers. We have both represented the UK at the World Sudoku Championships and the World Puzzle Championships. We're also "cryptic crossword" aficionados. Mark is the twelve-time winner of The Times championship and Simon is the former record holder for most consecutive correct solutions to The Listener crossword. We hope we can help your puzzle solving while also introducing you to some of the world's best puzzles.
Thank you for watching!
Simon and Mark

[@HoneyBun03]

whenever I see something he doesn't see I ask myself "am I a world-class solver?????"

[@DrThunder2004]

yeah, I do the same thing, but then he puts in like 6 other numbers and you are like WTF, how do you know those.

[@fehoobar]

Well, technically you live in the world and are a Sudoku solver, sooooo....

[@anybrody]

finding 2 pair number is almost equivalent to finding the real number. so it was easy to left out, even for pros

[@ScottieMacF]

I do that too. Usually it's because it's an easy find and he's on another part of the board figuring out something brilliant that I never could.

[@thomasfuhs5874]

That was me looking at the 5’s in row 9 for at least 5 minutes as he says 5’s are useless, and then he laughs at watching videos getting cross at obvious moves the solver miss.

[@jackfelder2560]

"When making these videos, your sudoku ability disappears." *beats the time of several world-class solvers*

[@majablomgren5315]

...WHILE explaining his moves o.o

[@averygaron994]

Reminds me of a common refrain my physics profs made in school: your ability to do math is inversely proportional to the distance to the nearest chalkboard

[@LucaBl]

@@averygaron994 isn't this the exact opposite though?

[@limitlessart6817]

@@majablomgren5315 yeah I’ve noticed because he’s explaining things he tends to miss a lot of things that would resolve his marks. Like the 46 pair which could’ve been solved by the bottom left 6.

[@jeppel1972]

@@LucaBl If you're standing very close to a chalkboard it will seem like the same thing

[@jeremiahcole7422]

Mom: what are you watching? Me: a guy on a computer trying to find naked singles

[@gregorybryan7437]

So did I!

[@cmknoll3]

Sounds like the plot to Wierd Science

[@BigGringus]

I know very little about sudoku. After watching his videos for a bit I get the joke XD.

[@AwesomeIronGuy]

r/surprisinglywholsome

[@farmerchuck7294]

I hope she knows what that means in sudoku terms, or that might not end well...

[@DisturbedNeo]

“6 minutes is a long time for a Sudoku” Way to make us all feel inadequate there, Simon 😂

[@luisgutierrez8047]

Its like saying "6 minutes is far too long to run a mile" when refering to Olympic sprinters...

[@luisgutierrez8047]

@Archie Bunker no. Contextualize it (dude was refering to himself when he said that- a pro sudoku player) and read my coment again...slowly.

[@MultiKeto]

won't like because you got 666 likes but yeah ...

[@ihorvoronchak8191]

I probably wouldn’t solve it after 6 hours

[@marksadplier9451]

Me who does hard classic sudoku in 12 minutes ☹️

[@mikedenrickbien6545]

"I'm sorry if I am missing what is staring me in the face" Me: Don't worry Sir, I don't see anything either

[@rewrose2838]

Gave me a good laugh there 😂

[@ShinningCrys]

"Dont worry simon, no matter how long i stare i dont think I'd get anything before you do"

[@kurtilein3]

I was staring at some 2X pair next to a 3, which is resolved because there is no V marking, for what felt like an eternity.

[@levstein]

"... but the way I did it was, frankly, far more beautiful." Love it!

[@suegeorge8694]

I laughed at that line!

[@Apollyonof666]

Something on would normally not think to utter for a sudoku. Simply amazing.

[@scottmcinerney9817]

I'd just seen the easy way to solve the number then he said that...

[@Zyphore727]

23:39 "It could have been resolved by that, but the way I did it was frankly, far more beautiful." 24:17 "I could do it by sudoku, but I'm gonna use this 3 to do it." This is why I love watching this man in my breakfast mornings

[@rose-annelafrance6422]

Ok... I found this channel yesterday through my recommended... And I thought nothing of it when I clicked on the video... But now, I’m addicted, and I can’t stop watching, this is fascinating

[@mrpapaya5324]

Same, it's addicting in a weird way.

[@bagelbytes2021]

Welcome

[@harunmandac7699]

same here

[@bruce4139]

Idk exactly I found thus yesterday also

[@ChaoticNeutralMatt]

Ditto except a few days ago

[@pradawithano]

“They’ve actually been useful. *Typical.*” You can feel the venom.

[@Kelarys]

The gall of this 5 to betray Simon like that. Outrageous

[@tomash9182]

That 46 pair in R6 could have been resolved by the 6 in C1R9 ages ago but 'the way he did it was, frankly, far more beautiful'.

[@pradawithano]

Tomas H Ah, yes. The greatest of all transgressions. Contribution.

[@pocky1scot1]

@@tomash9182 I was pulling my hair out at that.

[@jaeusa160]

Man, this puzzle is a lot harder when the presence of only X clues makes you forget the negative V constraint...

[@faddy91]

I did it without knowing the V constraint. Never done an X V before so I just forgot that rule. And it is actually unsolvable without the V constraint as the 1 & 9 in the top boxes can be switched without breaking sudoku or the X constraint.

[@davidsigley2846]

Yes! I gave up and started watching the video and had to stop it again when Simon reminded me of the V constraint

[@normalguy5583]

yes, i think that make those top 10 took so long, forgot about the v constraint and it's unsolvable

[@SoulmongerV2]

I got to the part with swappable 1s and 9s as well. Was about to comment if I'm missing something.

[@rhysbyt]

@@faddy91 I got stuck, found where he said "now that can't be a 3" at 18:36, got confused and looked at the comments and these ones saved me. Thanks!

[@MegaDrum1234]

16:56 - just me silently screaming at my screen about the 4 6 combo on row 6 by myself.

[@suegeorge8694]

Me too!

[@lexihumphries5170]

Me the whole time. I was waiting for him to spot it

[@rogerducrin]

that was me with the 45 combo on column 9 for 6 minutes lmao

[@MitchellD249]

@@rogerducrin At least Simon eventually acknowledged that his bigotry against 5s had led him to miss that one.

[@bogdancoman91]

Haha. I was searching for this comment.

[@fantafanta2823]

I don't watch these videos for people who can solve sudoku perfectly every time without missing any digits, it's for lines like "the way I did it was, frankly, far more beautiful" that make me genuinely laugh out loud.

[@petemagnuson7357]

Seeing the words "diagonal skyscraper" listed on the puzzle list fills me with fear.

[@chrisvids184]

simon can you actually do a diagonal Sudoku sometime

[@Dankman9]

@@chrisvids184 He's done some with diagonals.

[@northadventure5654]

"I'm not racing" -------did the puzzle faster than four of them while talking and laughing 😂and entertains all of us! Well done

[@kinouvisser4889]

I finished this puzzle in 2 hours and 7 minutes. I'm actually proud lol

[@kxlsin]

Congrats! I took an hour, but only had to swap 2 pairs of numbers around :(( i still count it as a win though; cause everybody "fails" because of mere mistakes, right? I just happened to be so confident when i put in the final number that I pressed check, before actually checking for mistakes, myself. Granted, this is also a first time i used one of the websites to actually complete a sudoku. how could you not have confidence when you reasoned out the puzzle and were able to fill in all the cells? x) so, I can't blame myself for having confidence, thus cannot blame myself for making the mistake, which means I still solved it.

[@ketanshah6613]

Great job😊😊😊

[@gustavooliveiramendonca9051]

Wow, congrats! It took me 3h24m to finish...I'm exhausted lol

[@genrr2361]

Two hours and half but it's wrong 4 am now, mby that's the problem

[@ashy-chan]

1 hour and 3 for me! Edit : The 19 pairs were hard

[@alvaropallete]

Simon took from 6:28 to 24:23, that makes a 17:55 solving time, which puts him in 8th position near to Kota Morinishi, very well done!

[@chiepah2]

17:12 to solve, He stops to wax rhapsodic about the puzzle construction for a bit.

[@EMoneyH]

@@chiepah2 He likely would be able to solve it even faster if he didn't slow down to explain his logic

[@nishanthn4927]

Not to mention, he’s TEACHING us while doing that!! I mean making us understand... I’d say he’s no.1

[@nicksm7980]

The contestants solve it on paper though. It is very messy and time-consuming if one enjoys their pencilmarks on paper.

[@gi0nbecell]

Matt Scott Well, I do believe that there is no attempt on the puzzle beforehand. At max, he sees a little of it while putting it into the software. Sometimes, he might spot one first bit of logic there, but the solve itself is indeed live.

[@brandanladikos6406]

16:40 It's really funny when I'm seeing this absolute genius doing magic and I'm just in my bed screaming "THE 6! THE 6!"

[@alexivanov6390]

what's more annoying about that one is it would've solved quite a few more squares

[@pesudozzz]

Beating the time of Snyder while explaining how to solve the puzzle. Impressive !

[@Urroner]

Simon was not under the same pressure bearing down on Snyder or maybe maybe Snyder just had a one off day.

[@billionai4871]

@@Urroner my guess would be that Snyder got stuck (for a little bit) on the trick at the top where the way to sum to 10 has to be different, got something wrong and the unwinding was terrible

[@PrasannaSeshadri16]

He definitely got something wrong. He was erasing multiple times and couldn't figure out the mistake. Sometimes under pressure you can get into a block like that and it's especially difficult in a puzzle with negative constraints to figure out a minute error. For instance you could have made the error in step 2 but dont realize that and keep erasing back to step 5 coz you are sure at least that much is correct. That kinda thing has happened to many top solvers before. Thomas has won 3 World Sudoku Championships and one World Puzzle Championship each of which involve consistently solving 100-200+ puzzles at the highest level, so this was certainly just a very bad one off instance, in an year where he was drastically out of practice already.

[@caiusmersa358]

I think using the app they use to solve puzzles for the channel makes it much, much, much simpler than doing this with paper and pencil also; being able to color \ highlight squares with the app makes a lot of things pop out, and you don't have to worry about messy erasing; I don't think you can really compare times of people doing it under championship conditions and ones using the app.

[@DavidLindes]

When I found this comment, it had 357 likes. I was searching the comments for 7's, to see if anyone talked about a thing... The 357 looked like a pencil marking. :D

[@lilbiscuitboi7668]

Me:*Notices a tiny thing he missed* Him: "I'm sorry if you see something that I don't"

[@zackv1094]

That damn 4,6 in column 1 row 6

[@lilbiscuitboi7668]

@@zackv1094 i know right?

[@Britske84]

@@zackv1094 I was screaming internally haha.

[@plazmotech5969]

@@zackv1094 for me it was the 5 4 in the last row that I noticed waaaay before him, I was screaming at my screen haha

[@Datectd]

@@plazmotech5969 Same 😂

[@nejckosanic4862]

Listening to Simon being cross at Mark for not noticing something whilst solving sudoku and me thinking at the same time "There's a five in the rightmost column, can you pleaaseee spot it!" made me smile. Thanks for the video, as always!

[@edwurtle]

He loves making pencil marks and loves ignoring them later :)

[@57thorns]

Yes, messing up those 5s he had already pencil marked. Especially adding one in r9c9 pretty early when he messed around with the digits.

[@dragonborne3277]

What got me was when he put the 2 in row 3 and not noticing the 3-7 pair next to it.

[@kittehkaosttv]

For me it was the 8 R6C6 Would solve the full of box 5 as well as the 10 value dominoes in box 2.

[@Schilani]

@@57thorns Also the fact that he pencil marked the 5s on the right, but not on the left, as they had exactly the same logic.

[@farmer2794]

Is it me, or does this puzzle seem a lot easier to follow than most of Simons other videos? I find myself understanding all areas of Simon’s logic on this puzzle, compared to the majority of others 🤷🏻‍♂️🤷🏻‍♂️

[@bot1024]

On some puzzles in here I spend 3 + hours but this one was just 40 minutes for me. The less sudoku is involved, the better I do (e.g. coloring suits me very well)

[@kaldo_kaldo]

Yeah, I felt like I could have solved this one

[@lebrigand4115]

When I discovered this channel a few months ago, I couldn't solve a sudoku unless it was a very easy one. Now, I'm able to solve a sudoku from the World Grand Prix Final in 40 minutes. So proud of myself! 😊

[@aibhlincreedon3604]

he got it in 16 minutes while he wasnt speeding and just playing for fun while beating 9 world chapions

[@dougdavis8367]

I enjoy watching and could never do any of the puzzles, but get all excited when I see something he missed.

[@TheFreeBro]

“That plane’s getting lower and lower.. wouldn’t want it to crash...” (sarcasm intensifies)

[@juliendurillon6343]

That would have been a good excuse for NOT SEEING THE TWO VERTICAL FIVES ON COLUMN 9 😠

[@danthiel8623]

Hehe

[@MrAirhead2010]

I finally cracked this one today! I was ABSOLUTELY chuffed - ok, it took me two days and half a dozen restarts and overall, I guess about eight hours solid brain-strain but I did it. Yeehaa! Then, dammit, I watched Simon solve it... In seventeen minutes with no mistakes. AND he explains what he's doing all the way through. He sure takes the wind out of my sails!!. (Actually that's not true - I am going to remember solving this one. For yonks! Yep, I'm still 100% chuffed.)

[@paulcook2961]

In response to Simon's comment about watching others' solve and shouting at the screen at something simple they've missed: This is bound to happen and is no reflection on the solver. People are bound to spot different things to each other. But what does surprise me is a systematic and predictable failure to spot certain things which I am getting used to now, having watched multiple solves by Mark and Simon. When I solve these puzzles, I am always worried that I won't find the next "magic trick" that will unlock the next step. Hence I am repeatedly going over ALL the mundane steps. E.g. as soon as I enter a digit, I cross check the whole row, the whole column, the whole box, the other rules etc. to see what it affects and if there's knock-on effect. Sometimes there is and sometimes there isn't. Sometimes I do this out of desperation - i.e. I can't find anything else to do. But I ALWAYS do that. I've noticed that Mark and Simon NEVER do that. They will eventually when stuck. But they will not do that first. As soon as they have found and applied a "clever trick" they immediately start looking for the next "clever trick" and thus often overlook mundane things. In a "clever" enough puzzle (i.e. one where the author's intended path is a series of clever steps) then their way is quicker and certainly more entertaining to watch than mine would be. Occasionally, we get a puzzle here that does not require such a series of clever steps, and on these occasions, my solve times compare reasonably well. This is one such puzzle: nothing particularly "clever" required - just repeated application of all the rules (particularly the negative one) and doing all the mundane stuff efficiently and without error. Simon DID perform a few "clever" tricks but I certainly didn't and they weren't needed. My solve time was 18 minutes which compares well with Simon (although he'd be much quicker without all the explaining) whereas usually I take 3x or 4x what Simon or Mark takes. So I'm sure everybody feels the urge to shout at the screen at something easy that's been missed, but does anyone else notice a consistent and predictable difference in style from their own? I'd be interested to hear.

[@Weirdman3214]

I do notice a very similar situation to what you were describing. So often Mark and Simon will have things pencil marked in and then place a digit, but not erase the relevant pencil marks. Then, as they continue to go through the puzzles and look at those cells they can occasionally miss scanning the row/column to figure out they've only got one possibility for a cell now. For me, I pencil mark in a rather overzealous fashion, simply because I'm not used to spotting tricks or because that's simply how I played Sudoku puzzles before seeing this channel - mark every possibility and then take them out as you go. So often times if I do start yelling at the screen it's only because they've missed something that they themselves put in the grid and is resolved (for the most part) using only the standard Sudoku rules. This is by no means devaluing the solves for me, of course. I still find each one I watch to be fascinating and I love seeing the little tricks that they end up implementing to get somewhere in one minute that it took me 15 to do. Also, playing with such ludicrous rule sets every day can certainly change the way you think about the puzzles fundamentally. Often times the regular Sudoku rules don't yield anything until a ways into the solve. So it's fully understandable that the two of them would overlook things that can be found using those rules. The difference in play styles is noticeable, for sure, but I agree that it is no reflection on the solvers, be it Mark and Simon or us as the viewers.

[@BrooksMoses]

Indeed, I've also noticed similar things. One of the other things I have noticed is that quite often the simple things that Simon or Mark "miss" are things that are sort of dead ends -- they don't immediately open up anything further.

[@bibliopolist]

"People are bound to spot different things to each other. " I think it would be really entertaining to have both solvers attempting a solve, while talking to each other. I guess there must be some puzzle type where this should be possible without being too distracting.

[@canebro1]

Yep, this exactly. My first reaction was "this is a world class puzzle, I'm just going to watch". About 5 minutes in I realize I can do it, and finished in 15:29 (albeit copying the numbers so far). Probably because I am really good at spotting negative constraints. However, Simon can spot Y-wings and swordfish in about 5 seconds but it takes me 10s of minutes of systematic searching.

[@MitchellD249]

In other words, Mark and Simon get so caught up in clever tricks that they tend to forget the basic rules of Sudoku from time to time lol.

[@arturslunga3415]

mfw I realize that the times in the scoreboard are cumulative

[@stevenvroom1041]

oh...

[@MattGriffiths81]

Thank you. I sat here listening to him 'reading' the times and wondering if he was having a stroke or I was.

[@catiehoppe]

What does cumulative mean?

[@MattGriffiths81]

@@catiehoppe it means each score is a total time so far. For example if I did three puzzles in 2 minutes each, a normal scoreboard might say: Puzzle - 1 - 2 - 3 Time - 2 - 2 - 2 But a cumulative one would say: Puzzle - 1 - 2 - 3 Time - 2 - 4 - 6

[@arturslunga3415]

@@catiehoppe It means that the the times in the table are not the times needed for the competitors to solve each individual puzzle, but instead the total time.

[@tarbosh917]

This is actually a really good puzzle to try out when you're new to XVs since it forces you to think about the negative constraint which is often the real trick to these kinds of puzzles.

[@blackbot7113]

I haven't solved Sudokus in forever and the way of denoting "guaranteed numbers" (the way you put them in the middle) is genius. I knew about people writing possible numbers on the top, but differentiating those from the "I know one of you has to go here" numbers is great.

[@mtgteeto5286]

Simon, I’m an absolute amateur at sudoku, but seeing you be so hard on yourself is quite tough! You’re an amazing solver and you have your ways. You’re probably better than all of us! Take the merit you deserve mate.

[@loyalugoff6479]

The sudoku sub culture is fascinating, I’m no good at puzzles like this so seeing how his brain processes problem solving is awe inspiring to me.

[@bertieboy3]

I've kept chickens; Never count your chickens after they've hatched as there is always one less the next morning.

[@richardfarrer5616]

But at least either you or the fox ate well for the evening.

[@tish5200]

@@richardfarrer5616 someone doesn't know that chickens are omnivores haha

[@davidanderson_surrey_bc]

@@tish5200 I had to google that one. You're right... chickens are indeed omnivores. Seems that wild chickens will not only search for seeds, but also insects and small reptiles or rodents. So maybe one of those chickens got itself a young piglet and had itself some tasty ham and eggs for breakfast that day. Yikes! What the buck, man!

[@Sauerkrautkopf]

The way it unraveled at the end was truly beautiful. Felt a rush of bliss when it all came together so neatly (and with 1:11:59 my time was at a point where I am decently happy with it, having only started doing sudoku again very recently)

[@Talis3]

Stopped watching, took the link. Never really did such a puzzle and finished in about 2,5h... then started watching you solve it in no time and the “negative V” hit me completely unprepared. I totally missed that this constraint was present, I only watched out for negativ X. That was fun, thank you! :)

[@MitchellD249]

I was proud of myself for getting in done in 2 and a half hours as well, but I had the negative V constraint in mind from the beginning. I'm just slow.

[@beastzerkerjet]

i really appreciate how the negative constraints first make one look at the puzzle with a blank expression then actually unlock the key to resolving the whole puzzle.

[@LHEBrandon]

I was so excited by this puzzle that I even exclaimed "what a puzzle!" at the end, going into full Simon mode

[@flobiish]

When I saw Mark talking about this yesterday, I figured this would be much longer of a video. Well done, Simon.

[@jackrudolf1745]

The first sudoku I've actually tried myself by clicking on the link in the description... solved it, time: 02:32:20 had to restart 15 minutes into the puzzle and was 6 minutes in the bathroom... how can one solve these in 20 minutes with having a clear mind the whole time? (you guys should really consider try it yourself, it takes time but it makes you feel so good when you get it!)

[@06wlund]

the fist few i tried took me an hour plus, some of which i needed help seeing things by watching the videos. Managed to do this one in 37m without help!

[@Kamikater2]

I managed it in 30min, but way less beatiful solved.... I got stuck 2 times where I had to guess to see if it works out or if I have to roll back. Doing a lot of killer sudokus helped with the 5s and 10s :)

[@ichliebebaeumeweilbaum]

Same it's the first one I tried myself, I did it in about an hour! I'm really proud of myself :D

[@MrLtShifty]

Just now I solved this masterpiece. The first of the more difficult sudokus I've solved without looking at your video for clues. Took me 85 minutes...

[@idw9159]

highly instructive, i never saw these xv puzzles before, well done methodical

[@markjsmith1960]

Simon -- Love the solving you do. One point I would like to highlight is a repeat of a previous comment you had quoted "It has been reported I have a problem scanning down...". I have seen what appears to be a clarification where you do scan down, after filling a cell in the top half, you miss the bottom cell (row 9), or when you scan up after filling a cell in the bottom half you miss the top cell (row 1). Thanks for keeping us all sharp!

[@OathofLight]

I haven't done a sudoku in at least 5 years, and have never even seen an x v puzzle. Took me a while to get the hang of it, and after watching you solve it, I can see how clumsy my approach was. Took just shy of 3 hours. Was fun!

[@BigGringus]

I can't believe someone can manage to keep me watching SUDOKU for 25 MINUTES!!!!! You are great!

[@davidtaveira3631]

did it in 31 mins, proud of myself. your videos and tips really helped me get better at this. keep up the good work

[@fourfingerculture]

The way he gets excited about a puzzle's beauty makes me smile every time. Love this guy.

[@binauralmashups7299]

"But the way I did it was, frankly, farrr more beautiful." - Simon 2k20, beautiful logic connoisseur

[@kickasyberg7344]

I did it! I totally did it. My time was 3 hours and 40 minutes, which is probably the worst solve time ever, but I also had to deal with a four month old baby and all that entails at the same time. I'm just so proud of myself for not giving up ☺️

[@tovekauppi1616]

10:07 there is a beautiful piece of logic that can remove the 37 option from the domino in box 1. If it was a 37 pair, that would place both 3 and 7 in the first row in box 3 (because of the 37 domino in box 2). This is impossible, since neither 3 nor 7 can be in r1c7 due to its relationship with the 37 domino in box 2. That would leave 3 and 7 to be in r1c8 and r1c9, which goes against the negative constraint.

[@erwanmorvan8168]

Well played

[@McofCOD]

I've learned Sudoku ENTIRELY from watching you periodically for the past few years and solving sudoku on my phone. I took a stab at this one without assistance and did it first try in 1:06:00. I'm honestly happy with the result given how long it took some "world class solvers" to do. Keep making videos!

[@liriosogno6762]

"6 minutes is a long time for a Sudoku! " It takes me 15 minutes to do a medium one 😂😂 But idc i think its fun. I don't need to good at puzzles to enjoy them

[@gamesloveD-jo8zv]

This puzzle took me a bit over an hour to solve, mad respect for your time.

[@igorporfiirio4915]

maybe thomas forgot about the 5 restraint. I'm saying that because I forgot, of course, I'm not as used to this as him, but because there aren't any Vs on the puzzle I totally forgot them, and maybe the same happen to him or some others that tried this puzzle.

[@SurfyTurnip]

I am a simple minded person so I'm looking for classic sudoku solutions and sometimes I find them, but he's not looking for them at the moment so I feel like crying from relief when he finally realizes them. This goes to show how differently our minds work. I do follow the rules but my mind automatically looks for classic sudoku solutions when I've used one

[@peterhackett3815]

26:43 my solve. Quite proud of that comparing it to the pros times

[@minerva5025]

I'm addicted to Sudoku for a long time and now seem to become addicted to watching sudoku solving videos, I can't explain the beauty of it and here I don't need to try, we all know about the power of Sudoku wonders

[@fulltimeslackerii8229]

That “unimportant 5” literally was the final piece needed to solve the entire rest of the puzzle hahaha

[@jonnyphenomenon]

I finished it! in an hour and 45 minutes... I paused your video and worked on it for a bit, and would get quite far before resuming your video when I would get stumped. I am proud to say that I did stay "ahead of you", as each time you would start getting caught up to where I had got stumped, I would get unstumped, pause your video, and fill in a bunch more squares. It is a real phenomenon that it is easier to spot the obvious things when you are watching someone /else/ play. Its like looking over someone's shoulder while they play solitaire and saying "Why don't you put that 8 over there?" I play a "board game" version of sudoko called "Colorku" with my friend that uses colored balls instead of numbers. The cooperative nature of it makes it quite enjoyable. very different from filling out sudoku's by yourself. It has no viable method of annotation, so you have to check each others work, and explain your logic for each move. I highly recommend it.

[@timparenti]

So much British understatement in this one. Just what I needed today.

[@rufus5208]

This is what I absolutley love about KZbin. You find out about so many niche hobbies filled with passionate people.

[@shoaib1247]

This puzzle had moments of deep silence to plane flying sound. Amazing

[@swimrski]

I just started doing Sudoku one month ago. A customer gave me an Easy Sudoku book. I've been doing two a day, and they really are easy. I loved this and the process used to solve it!

[@81Cells]

As someone who was invited to take part in the 2017 finals but declined, and watched them from the audience instead, I feel like a piece of anecdote is in order. First, you have to know that right before the GP finals start, the audience is given the set of puzzles that players are going to have to solve, so that they can have a try at them in real time. I did not attempt the puzzle myself back then, but I was sitting next to my teammate Timothy Doyle and I watched him solve it - he made it look like it was trivial and was done in at most five minutes. Then we watched most of the finalists lose their minds on the same puzzle for ten, twenty, thirty minutes and more. It was really a bit of a supernatural moment.

[@PrasannaSeshadri16]

Ya I remember that I tested it in a fairly quick time too. I suppose competition pressure mixed in some kind of special way to befuddle all of them except Seungjae.

[@paulbelanger7383]

Stress and self-induced pressure can make thinking logically, quite difficult.. I'm a champion at 'solving from the bleachers', but ask me to compete... No thanks 😅

[@richardstolk9815]

As coordinator of the Dutch submissions, I tested this one myself in around 18 minutes and I always apply a factor 3 to my times compared to the world top players. So my guess was that the majority of the finalists would need 6 minutes. Arvid and I were more and more surprised with every minute ticking away seeing all the struggles on stage. And we both were very happy that at least one of the top players finished in a decent time... Our guess was that most players didn't find the trick that Simon found very early in the solve.

[@GAGarrett7]

I was wondering if you had a sense of where the problems were in the solves during the competition? I guess that in setting puzzles there are different goals, but when the symmetry of the solve broke down in Box 1, I continuously found myself going back and trying to find the clever fix (or force it) whereas if you just kept on the correct solve path like Mark's video, it sorted itself out, although rather late.

[@PrasannaSeshadri16]

@@GAGarrett7 we actually had a contest at Logic Masters India recently that had a very similar occurence. There was an AntiKnight Sudoku that I solved in 8 minutes and I took the contest when it started so I just thought it's a normal solve. Turns out that puzzle defeated pretty much everyone else and propelled me to my first ever first place finish on an LMI contest because these solvers who are all usually better just stumbled badly on it with 20 and 30 minute solves. The connecting factors in this puzzle and that one are 1. They both had one narrow deduction that you have to spot or else you won't proceed. Here it was the restriction of the pairs on adjacent columns like the 37 pair meaning that 37 can't come in adjacent cells and the subsequent quadruple. Quadruples are pretty rare in competitive solving so maybe a lot of them didnt see the need to follow that through to its logical conclusion and looked for something more direct. 2. They both had negative constraints. Such puzzles are far easier to mess up and far less conducive to bifurcate on if you do get stuck because there is a lot more to keep track of on a bifurcation chain. 3. Neither had a pre contest indicator that they would be difficult. The AntiKnight I mentioned didnt have the highest points attached to it compared to other Sudokus on the contest, and the XV was the second puzzle of 8 and you kinda assume an escalation to happen. You are more prepared for puzzle 8 being difficult for instance.

[@carcarskizm1357]

You were correct when you were saying that people would be shouting what they see when they see something before you. I was for some but then you come up with some other things that baffles me. Always love your videos.

[@marksadplier9451]

Thomas: 50mins is the best i can do? Simon: how about 17minutes? With explication of my action with that? Rip Thomas

[@grahamroberts2050]

Only recently discovered this channel and often hit a wall very quickly with anything but the GAS puzzles but really thrilled to complete this one in about 30 minutes - a lot of obvious staring me in the face so actually frustrated it wasn’t faster. Love your videos, thank you!

[@jimkyle8008]

This was marvellous and it's remarkable how Simon can fill in a flurry of numbers in a flash. I was just wondering, though, if in Championship competitions software like this is permitted, or whether the competitors are restricted to using pencil and paper or whiteboards with erasable marker pens. If they have to do things manually, this would slow them down considerably. Can you imagine having to write in pencil marks and erase them by hand at speed? I would imagine the possibility of rubbing out the wrong number is also increased.

[@chancehester2551]

Mind boggled at how fast you solved it, let alone a 6 minute solve. As soon as I noticed an obvious answer you solved it from a completely different angle. AW inspiring!

[@edensaquaponics1941]

My time ended up as 54:03, however that included the 15 minutes my iPad takes to lock after I fell asleep and several more minutes where I lost concentration. So realistically my time was about 35 minutes with a sleep break somewhere in the middle.

[@mensamoo]

I completed this puzzle over 3 days in 4 sessions. When I watched your completion I found it in a much different order to mine. Like you mentioned we all miss the obvious. I could hear a thousand viewers screaming on 17:00 about R6 C1 . The 6 was below it begging to be seen. Much enjoyed! Thanks.

[@latentradiance1650]

simon : talking about getting cross watching other sudoku videos where the solver isnt noticing something obvious me : SIMON ROW 6 !!! THE 4 AND THE 6 !!!!! THE 4 AND THE 6 !!!!!!!!

[@ImWreck]

I don’t know how to play soduku and have never tried, but I watched this whole video, had no idea what was going on and enjoyed it. You have a calming voice

[@sciverzero8197]

I noticed that in focusing on the negative rule, you failed to spot about half the puzzle's worth of plain sudoku box fills, that may have cut your total solve time in half had you had those to reference. In particular the 4564 in the outer corners of the lower half of the puzzle could have been solved before you started deducing the majority of the X clues. That's the only big thing I noticed that you missed.

[@Snowdrop-bt2wz]

It took me 55 minutes to do this sudoku, I am ecstatic! Watching these videos has definitely helped me to improve my sudoku skills.

[@MichaelGreen831]

Was having this convo about some news event. It got depressing. Needed to find an escape. Where do I go? SIMON!!! Thanks for making my day better! time: 50:15 no help! YAY!

[@theepicsnail]

Absolutely beautiful solve. Impressive. Keep it up! I enjoy when we see different things in a solve. Usually when I'm staring at one thing thinking it's obvious, you're spotting things I was completely oblivious to. It's always interesting to see how many different paths there are through a good puzzle.

[@DJejbarros]

It is so rare to complete one puzzle... and I really loved this one... it took me 20 minutes... a miracle... usually it takes me two hours

[@DJejbarros]

and guess what... my quick awesome flawless solving was completely wrong !!!! I did blocks 7,8,9 correctly... but boy, I inverted one "domino" on top and all other lines and columns were wrong :-D It was "happily disapointing" :-D

[@codingbloke]

Really nice puzzle. Had to laugh at around 19:00 when Simon mentions how frustrating it is watching Mark not spotting stuff just as we must be watching him. All the while that 8 in box 4 was driving me potty being a given yet didn't eliminate the 8 in the R4C5 when first added, it took until 22:45 but even then didn't get rid of the matching 2 (by X) in R3C5

[@daniellevine6131]

11:14 *screams at the screen for simon to place a two in row 8 column 9*

[@generic_youtube_name3]

worse at 16:39 to place the 4 and 6 in row 6, but instead writes a 46 pair at 17:01. Still an incredible solver

[@johns1307]

This is definitely more of a practice thing. Training yourself to bring up the right mindset, the right set of mental parameters to spot the types of patterns that tend to emerge from this specific style of puzzle. Time taken is more like time spent practicing, but simply being able to do it at all is a sign of skill.

[@Coyotek4]

30:04 I thought I got off to a solid start and bogged down halfway through ... but anymore, I was able to do this one without guesswork. I'm pleased with how I did on this one. I'd comment about how I did better than Tom Snyder, but it's a poor comparison as I was under no pressure to do well here; no time limit or competition. I doubt I'd have done so well in such a circumstance.

[@psychospin1]

I stopped the video at 7 minutes to try to do it myself. I've been following this channel for over a year and I've rarely been able to solve the sudokus. I don't know how but I managed to solve this one. And it took me only 50:11. I still can't believe I made it happen....

[@pulos42]

I would love to watch a reaction video of you re-watching this solve. I want to watch you scream at the screen at yourself

[@ruru2500]

that 45 pair on the bottom right being solvable for what seemed like half the video was exactly what you described it to be! Drove me crazy

[@sotek2784]

I got a good chunk of the way in then realized I broke it and couldn't figure out how to fix it so I gave up, but I did have one piece of logic that Simon missed - at about 10:00 he could resolve the box 1 X as being a 28 pair, because if it was a 37 pair that would have created an X-wing that would have forced the 3 and 7 into row 1 in box 3, and there was no way to satisfy that. (Can't use column 7 because then you need one in row two, can't use columns 8 and 9 because then you need an X...)

[@AdalynnCaelgirien]

I've always LOVED sudoku and I only just now learned that there is an entire youtube channel dedicated to solving it? That subscribe button got smashed. This is incredibly relaxing to watch!

[@Afterthoughtbtw]

14:28 for me. That was a beautiful puzzle to solve, working my way up the grid as everything cascaded into place.

[@legionfire6439]

I have never seen sudoku done in this format and I actually really like the way you have to think to solve this format 10/10

[@S_Black]

In Row 9 you missed that 3 can't go next to a 27. That may have been a little quicker

[@brianarsuaga5008]

I really love these XV puzzles. 1 hour 24 minutes for me, but one of the rare puzzles on this channel I can do without going back to the video for help!

[@nekogod]

49:28 Loved this, was fun and very approachable

[@leftysheppey]

You were on form today Simon, not just in puzzling, but your humour was spot on too

[@TrackpadProductions]

Simon spends a good amount of time explaining the logic of the puzzle. He'd probably shave off a significant amount of time if he were actually speed-solving.

[@dan200smx7]

While I do think its impressive, you can tell that even while he's talking his brain is flashing around looking for the next bit of logic, so the time spent talking is probably not quite as wasted as it looks

[@dan200smx7]

@1E (06) Lo Chun Lam yeah the most impressive thing to me is how fast he can do it with using only logic, no bifurcation or what not

[@Zukasaproductions]

Took me 73 minutes. Feeling pretty good about that! The first one of those you presented I actually managed to solve myself (only did classic and killer until now)

[@MyNarsa]

14:06 but the software makes this a lot easyer to keep track of "pencil marks"

[@mosesembrey323]

I’d imagine that the situation that you and mark are in, being phenomenal solvers who record themselves, you experience something similar to a chess phenomenon where the best players in the world are often unable to see simple solutions, whereas fairly inexperienced players notice them immediately. The reason that this seems localized to the two of you, however, I believe is because most solvers don’t have hundreds of thousands of people watching them.

[@TheWakeJumper]

Bruh when he had 46 on the far left it had to be 4 becasue he had a 6 in the bottom left corner and he didnt see it for so long

[@danielsosexy3118]

facts bro and then he started talking about how he was watching this one dude who missed obvious stuff 😂

[@samicheikhelchabab9120]

YES IT BUGGED ME FOR SO LONG!

[@ella-aliina]

This was driving me insane!

[@Indie_Calls]

I was feeling that way about the 5s at the top of the far right column, thinking that if those are the only spots a 5 can go, then that effectively solves the remaining 4-5 cells in the bottom right box.

[@johna7908]

I've barely ever played sudoku in my life. But about a month ago I saw one of their videos, and I've been hooked since.

[@nathanialblower9216]

Just in case there are any logicians out there trying to understand the rules: “ALL” means “All and only”.

[@TheReal3ality]

it only took you about 17 minutes whilst explaining moves and filming a video. simply brilliant