The Simple Trick For Hard Sudokus

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3 жыл бұрын

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Rules:
Normal sudoku rules apply. ie fill each row, column and 3x3 box with the digits 1 to 9, exactly once each.
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Rules:
Normal sudoku rules apply. In cages digits sum to the small clue in the top left corner of the cage. Digits cannot repeat in a cage. Clues outside the grid give the sum of the cells on the indicated diagonal. Digits may repeat along the diagonal.
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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

Пікірлер: 752

@DonnyTheNerdfighter 3 жыл бұрын

Before watching this puzzle I'd never figured out how to find hidden pairs. I genuinely learned something in today's puzzle. This video should be flagged as essential sudoku learning material.

@swingasc 3 жыл бұрын

Agreed. I was stuck, then came to his solution, and once he pointed out how to spot a hidden pair the puzzle was cake.

@banja9172 3 жыл бұрын

Exactly the same here, once he showed how to find 37, you easily find 27 and the 4's in row 7 and that brakes it open...

@Paolo_De_Leva 3 жыл бұрын

Agreed. Not only about finding hidden pairs, but also about using them to identify possible singles they create in their house (column, row or box).

@marshallpyatt5425 3 жыл бұрын

Agreed. I need to start working on finding hidden pairs.

@nickjohnston3763 2 жыл бұрын

@@Paolo_De_Leva j

@lukostello 3 жыл бұрын

His pattern finding skills are off the charts

@theresalouise1716 3 жыл бұрын

So are his 'getting to the point' skills

@StorymasterQ 3 жыл бұрын

What about his 'spotting naked singles' skills?

@jdyerjdyer 3 жыл бұрын

On naked singles, as long as they give you their digits, why not take them?! ;)

@GPCTM 3 жыл бұрын

and yet: 18:04 : there's a determined 4 in the 6th box, now; ready to go in. He's scanning 4's. 19:35 : he got it. What I'm saying is: don't be scared.

@dexterjau3 3 жыл бұрын

Technically they're all on the chart 😝

@molaeiali 3 жыл бұрын

First digit after 16 minutes, whole video is 22 😅 what a key to the puzzle

@HalfBakedLunatic 3 жыл бұрын

Yeah, the break in was quite a ride!

@BozoTheBear 3 жыл бұрын

"When you see extremely intelligent people talk about difficult things, the fluency with which they do it is so impressive." Pretty much sums up your videos, Simon!!

@prahas777 3 жыл бұрын

I thought exactly the same thing.

@956675 3 жыл бұрын

I thought the same when I heard that.

@kev4241 3 жыл бұрын

The amount of mental organization, grouping similar concepts, and grasping of the essential they have achieved in their struggle is evocative

@zackvolturo8032 2 жыл бұрын

Is this quoted from somewhere?

@BozoTheBear 2 жыл бұрын

@@zackvolturo8032 - yes, it's quoted from the current video.

@anandkulkarni8313 9 ай бұрын

His pattern recognition skills amaze me. I would have never been able to solve this sudoku without those big hints of hidden pairs. Kudos to Simon.

@stevepinard5826 3 жыл бұрын

A Paper Tiger. Never seen a puzzle with such a difficult break-in collapse so quickly and completely. Sadly, I wasn't in the mood for a difficult start, so I let Simon do the hard work.

@RO8s 3 жыл бұрын

I tried and hit the wall - couldn't find that first number. It's all it took though, the rest was a pussycat.

@david203 3 жыл бұрын

There may be an inverse relationship between difficulty of finding the first number and the difficulty of finding the rest, and similarly for finding the first k numbers and the remaining numbers. But this would be countered by puzzles where the first number is obvious: in such puzzles the remaining numbers are usually fairly obvious too. And it would be countered by puzzles where the first k numbers are very difficult to find, requiring recursive calculations, because the remaining numbers can also be difficult to find. Summary: never mind.

@bobhoover1624 2 жыл бұрын

@@david203 p

@david203 2 жыл бұрын

@@bobhoover1624 q

@boman2000 3 жыл бұрын

Solved it! Used 2 pencils, a blowtorch, a couple eyes of newt, a rebuilt Flux Capacitor, beef jerky, and a realization that "there is no spoon." Once the owl bobbinsed out of the radio and we filled the tires with pie, we discovered my preciousssss, and the hidden pairs leapt out like dark from night. Easy peasy. Well done Simon, brilliant as always. Marking this for re-watch to learn how to spot those hidden pairs in less than 13 days with a reverse time loop.

@katecrawford9966 3 жыл бұрын

I just LOVE how polite and kind Simon is - a pleasure to watch you solve!

@steviedmrbk5179 3 жыл бұрын

*Looks at the video length* ..."hmm, 21 minutes, I'm havin' a go of this..." 4 minutes later..."nope, nothing!" 🤗🤗

@FirstLast-gw5mg 3 жыл бұрын

There's a swordsfish on 2 in columns 1, 5, and 9 (2 is only possible in rows 3, 4, and 8 in those columns). Removing the 2 from the rest of those rows leaves two places for 2 in row 8, which also are the only places for 4 in that row, so it's a hidden pair on 2 & 4. That restricts the 7 into a helpful domino and there's only one place for 7 to go in box 2. That was how I broke into the puzzle.

@igoretski 3 жыл бұрын

@@FirstLast-gw5mg Wow. Impressive. That quickly solves all the 7's in the puzzle. Then you also find the 2 in column 4 must be in box 8, where the 24 pair is and thus get the 4 in box 7, like Simon.

@nguyenn7729 2 жыл бұрын

@@FirstLast-gw5mg ye I solved it using the 2's and 7's swordfish which give a 156 triple in row 8 c4,5,7

@MartsGarage 3 жыл бұрын

15 minutes in. Not a single digit placed. Time to see how Simon does it. Edit: Wow. It seems so simple but I wouldn't have spotted it in a million years. Thanks Simon. Oh yeah, nice intro.

@Fabroskii 3 жыл бұрын

At 13 minutes I was questioning whether this was part 1 of a multi-part series lol Well done Simon !

@markme3259 3 жыл бұрын

Fast forwarded

@jhuggett1938 3 жыл бұрын

what does lol mean

@acestar01 3 жыл бұрын

@@jhuggett1938 Laugh Out Loud

@Oss-6342 19 күн бұрын

@@jhuggett1938laugh out loud

@SlovianMapper 2 ай бұрын

I absolutely adore those rare and short moments between "sorry, this is not going well" and "oh, this is interesting". Applies to almost every "classic sudoku" type of puzzle being solved by Simon. My most recent hobby, thanks Simon!

@Keldorn01 3 жыл бұрын

My time was 36:46 on this one, and I've got Cracking the Cryptic to thank for that. A year ago I knew precisely zero sudoku techniques, not even naked singles, and now I'm spotting two swordfishes leading to a hidden triple

@andreaskraft5145 3 жыл бұрын

I did exactly the same thing as you did. When I saw the offset patterns, I straight away started to look for swordfishes. This is also because I have watched Simon solve sudokus here on CTC, especially tattooing sunsets. I think my time was about 10 minutes longer he yours, but I don’t know exactly because my browser reset after my first 20 minutes and I had to start all over again. But definitely a fine time time you got there.

@RasperHelpdesk 3 жыл бұрын

Nice to have a puzzle that doesn't require solving a system of equations to start ;)

@sgarcata 3 жыл бұрын

no kidding... I've put doing Calculus proofs behind me although I have to say I loved doing them in my 20's.

@grenvillephillips6998 3 жыл бұрын

I loved that one. It was like seeing a lock being picked.

@guanyin19 3 жыл бұрын

This was definitely a puzzle to highlight the importance of hidden pairs. There are also a couple of swordfishes on 2's and 7's in rows and columns 1,5, and 9. However, the puzzle is more quickly solvable by spotting and using the hidden pairs instead.

@bexwiedasbier 3 жыл бұрын

Really love when Simon gets out the guitar

@finleyherrmann4048 3 жыл бұрын

Haha the casually roasting Mark for probs bifurcation made my day.

@jadenshah 3 жыл бұрын

Sweet home alabama was the last thing I expected to hear during this into

@RootballJohnson 3 жыл бұрын

And from a Brit who says, “Bobbins!”

@Frie_Jemi 3 жыл бұрын

You ran out of gas on the 4s while you clearly still had to half a tank...

@christopherdavies7213 3 жыл бұрын

Who else was shouting at the screen at that point?

@onedwinone 3 жыл бұрын

@@christopherdavies7213 I laboured through the start, notes everywhere ,had to watch to get the hidden pairs and then bamm 15.46 he missed the fours and I was away , so pleased with myself but without Simons great skills I would have had to give up. Not all my own work but still a good feeling , thank you.

@SamCoca 3 жыл бұрын

@@christopherdavies7213 Yes, the 4’s should have kept moving. Lol.

@rweisele 3 жыл бұрын

Finding the hidden pairs has been a key that I discovered some time back, and though I do it a little differently, it is still the key that unlocks some of these classic puzzles. Without using the technique of finding 'hidden pair' you are really in the dark trying to solve some of these!! Thanks, Simon, for reassuring me that I am a true Sudoku solver, and I love watching you do the really tough 1, 2 and 3 digit starters!!

@_-_-Sipita-_-_ 3 жыл бұрын

Steps: 1.Look at the 2 and 7's pencilmarks, with the pencilmark loop logic you can cancel some cells so they are not 2 or 7's. 2.With the positions of 2 and 7's you will notice that they always occupy R3C5 and R8C5, so its a 27 pair. 3. Solve the 4. 4.Solve the rest with simple sudoku logic.

@_mnejing 3 жыл бұрын

Absolutely the simplest way to do this puzzle. The 2/7 pair jumped out at me, and the puzzle literally fell apart in a matter of 5 minutes. It took me 2 attempts (first didn't see the 2/7), the first attempt ate up around 15ish minutes of my time, but restarted, found the 2/7 quick, and was done in under 7 mins. It's a weird one. It's fun reading the comments about using swordfishes and slot machines and all sorts of random stuff, when it's whole linchpin is a 2/7 pair.

@fherozzz1 3 жыл бұрын

@@_mnejing can u pls explain what a hidden pair is and how to spot it/them. A rookie sudoku player enquiry!

@frselsig 3 жыл бұрын

I think there's a swordfish on 2s at 8:30 - r4c1, r8c1, r3c5, r8c5, r3c9 and r4c9. Not actually tried to see if it makes any difference, but it looks like its there.

@yura_riabov 3 жыл бұрын

Also spotted that

@bobjonson3528 3 жыл бұрын

There's swordfishes on 2s and 7s in columns 1,5 and 9 and in rows 1,5 and 9. If you look closely, you can spot that all digits in the rows and columns 1,5,9 align. After that I looked to see which digits don't appear as givens in those rows and columns, and those digits where 2 and 7. Than I looked to see where would those digits be in those rows and columns and realized that there are 4 swordfishes in total, all of them being either a swordfish on 2s or on 7s.

@_mnejing 3 жыл бұрын

@@bobjonson3528 Overcomplicated, there's a simple 2/7 pair in C5 that decimates the whole thing right from the start.

@Buizerd88 3 жыл бұрын

there is also a swordfish on 7s, combine those and you get the hidden pair 2/7s. with that, its doable.. I assume there is also something going on with the 3s, but as far as I could tell its not a swordfish

@snjyjn 3 жыл бұрын

When I attempted it (without watching the video), I pretty much pencil marked the whole grid, and then found the swordfish. After that it was quite easy to solve. The difficult part was spotting this swordfish.

@GevinShaw 3 жыл бұрын

Very happy I noticed those 37 and 27 pairs, not by seeing the pattern in the givens but by methodically working across the rows and down the columns. Definitely made the puzzle manageable. You know, as long as you don't screw up unrolling a pair four moves from the end.

@Anrui_Ishi 3 жыл бұрын

I found a swordfish on 2s at the beginning... I got so excited that I spotted it that I promptly forgot what I was supposed to do with it,..... Facepalm

@mepiffi 3 жыл бұрын

Finished at 42 minutes, finally I felt that the weeks of watching the channel and working with the apps payed off! Swordfishes on 2s and 7s were my break-in. Thank you Mark and Simon for strengthening my skills!

@user-bf3xl8de7j 8 ай бұрын

Are you able to train me for two hours in sudoku?

@TeoElryns Жыл бұрын

I've finished it in 20:56, i consider myself amateur trying to solve hard sudokus recently, so i consider this as an achievement :D

@dvkprod Жыл бұрын

I love the bassy sound of your keyboard, it really adds to the incredibly emotionally soothing experience of your videos, which in some weird way cohabitates with and even enchances the intellectual side of the subject at hand.

@joekerr3638 3 жыл бұрын

“For Bifurcation I give him no credit. “ What about partial credit?

@jbftcmof 3 жыл бұрын

I think they should split the credit.

@tabularasa0606 3 жыл бұрын

Nope, 0 points for Marc. All 10 go to Simon!

@ordinaryhuman5645 3 жыл бұрын

No credit implies no partial credit.

@lsmart 3 жыл бұрын

Well, you either consider it cheating or not. If it's cheating, you get a zero.

@rohanmathew7577 3 жыл бұрын

Whats a bifurcation?

@TheLukeskywalker2 3 жыл бұрын

I am so proud of myself for noticing the 2 swordfish on columns 1, 5, and 9 without Simon noticing it.

@MiguelGarcia-to6cs 3 жыл бұрын

How do they work?

@TheLukeskywalker2 3 жыл бұрын

@@MiguelGarcia-to6cs The Tatooine Sunset video that Simon explains them well.

@TheLukeskywalker2 3 жыл бұрын

kzfaq.info/get/bejne/irdgn9agmcyuqp8.html

@Buizerd88 3 жыл бұрын

just 1 small step further and you would have cracked the puzzle, there is also swordfish on the 7s, and combine them and you get the hidden 2/7 pair

@ericcrowell9493 3 жыл бұрын

@@Buizerd88 That was how I solved it. I was genuinely surprised that Simon didn't spot the swordfishes...

@stratolightdude 3 жыл бұрын

whenever I feel sad or down ...., i just have to watch Simon solve a puzzle ..., ANY puzzle. :-) Thanks so much for the great tips from this one. VERY.USEFUL!

@BryanLeeWilliams 3 жыл бұрын

I am just looking at this puzzle before I start and noticing the beauty of it. In the left 3 boxes are the numbers 1 to 9 once each, the in top 3 boxes are the numbers 1 to 8 once each, in the right 3 boxes are the numbers 1 to 9 once each, in the 3 middle horizontal boxes are the numbers 1 to 9 once each.

@pardox28 3 жыл бұрын

50:09 for me. I used the slot machine method to get where the 2s and 7s were in the grid. Got stuck for a few minutes & then noticed in column 5 that there was a hidden pair of 2s & 7s where Simon spotted them much, much earlier than I did. From there the 4 unlocked the 2s & 7s & it was easy from there on out. Super fun Classic mainly because the techniques that this channel has taught me are finally becoming ingrained in my solving. So thanks so much, Simon!

@SallyJaneRobson 11 күн бұрын

I love Sudoku. My brother sent me a link to your site. It’s such a pleasure listening to your enjoyment unfolding the puzzle. I like to search for the patterns of three corner numbers throughout and their overlap with other three corner numbers and then work from as to what is excluded…

@victorducedre5776 3 жыл бұрын

8:56 to solve. This channel is definitely helping my out-of--the-box (in-the-box?) thinking and observation. Eight months ago I couldn't tell you what a swordfish was, and now I lucked into two of them. Edit: Swordfish on 2s and 7s revealed the hidden 27 pair, which led to the 4 in r8c1, which resolved both swordfishes.

@BrianBernardEngineering 3 жыл бұрын

Can confirm, it's an absolute beast without finding the hidden pairs

@rblossey 3 жыл бұрын

yep, I needed a finned jellyfish on 8s-eventually reducing to a swordfish (in the other direction)-to solve it without the hidden pair!

@KyleWitten 3 жыл бұрын

@@rblossey I had to do complete notation to solve it on my own, but a naked quad in column 5 unwound the whole thing.

@rblossey 3 жыл бұрын

@@KyleWitten this is one of those puzzled that deserves a second solve! I will try it again and look for that ;) I was a hairs breadth away from writing in all the candidates too! had I been doing it on paper--without that convenient coloring feature--i probaby would have!

@bananacat9139 3 жыл бұрын

I've solved more sudokus than I've done in my entire life. You inspired me back to play with sudokus and I love it so much. Thank you. And It's very addictive.

@HerveAttia 3 жыл бұрын

video starts at 4:52

@TheGuitarded1 3 жыл бұрын

Thank you! Guy kept rambling on like it was never going to happen.

@guzideerden6523 2 жыл бұрын

Thank you

@Swimming_with_Josh 2 жыл бұрын

Boi the video starts at 0:00

@shoeliuscaesar 3 жыл бұрын

Simon: “Kevin you are a naughty person sending this in” Kevin: 😈😈😈

@andrewnelson2525 3 жыл бұрын

My first digit in the grid was at 27 minutes (the 4 of course). Solved by 33:50. Quite satisfying how it quickly unwinds after the beastly break-in. I was amazingly sparing with pencil marks (for me). Following the influence of this channel I limited myself to two marks per box or cell except for column one which I filled in all the possibilities in an act of desperation before I finally spotted the 27 hidden pair. Loved it.

@ivarskursitis601 3 жыл бұрын

Spent 30 mins with no progress. For kinda reason thought this will be possible by looking at the video length :D

@Zasqdddas 3 жыл бұрын

I usually go by difficulty being proportional to video length. I went through all of the numbers, and was only able to place a couple of pairs. This puzzle wrecked me. I gave up on a logical solve, so I bifurcated by assuming a "2" in the top right of box 6, and wound up with a contradiction filling in 7s. Once I had placed a single digit correctly, it was a straightforward puzzle.

@SamAshworth91 3 жыл бұрын

I did the same, I tend to use around 25 mins as my break point, but got nowhere with this.

@rheffner3 3 жыл бұрын

I have no idea how you do these puzzles no matter how many times I watch them. But I still watch them.

@david203 3 жыл бұрын

Most of the basic solving rules used here are easy to derive from the definition of sudoku. And the more complex rules involving patterns, that are not easy to derive, weren't even needed here once the first few numbers were found. The most difficult puzzles that require recursive trials to find every number cannot be solved by a small set of simple rules at all. I'm saying this as though it is fact when it is just my opinion, so can anyone please correct or confirm this hypothesis?

@weskingston264 3 жыл бұрын

I feel kind of proud about this one! (24:44). I cracked this pretty easily, but ONLY because I knew to look for shenanigans (because this is a puzzle on CTC, after all)! I was channeling my inner Simon in the beginning systematically making my pencil marks, and noticed that I couldn't fill in many pencil marks constraining to just two locations, but there were many locked to three positions, so I figured I'd return to those once I'd done what I could. Then my spidey senses were tingling saying 'look at the 2s and 7s'. Once I realized there were only two possible configurations of the 2s and 7s (because of how they were locked in column 5), I channeled my inner Mark and bifurcated. My first go was looking promising, but was ultimately a bust, so I reset and sailed through the puzzle after that. I'm curious to see if there's a logical way to figure out which path was correct! Watching the video now!

@gracievallee2551 3 жыл бұрын

I am an amateur with sudoku who has started to do some sometimes puzzles for the challenge and I was very excited to hear you say that you only write notes in boxes if there are only two possibilities because I also do that! maybe everyone does it but I was proud of myself

@raymonlinares7342 3 жыл бұрын

It was the same for me too! I felt like a genius for a little while.

@matejailisin3194 3 жыл бұрын

I'm so proud of myself for getting this one just like Simon did (tho it took me 36 minutes). If not for this channel, I wouldn't even know where to start. Thanks guys, you are amazing!

@johnkey350 3 жыл бұрын

Ever since that video when Simon marked cells eliminated by swordfishes by a center pencil mark, swordfishes have become so much easier to use once they're found. Def recommend. Took me 25:06 with a distraction in the middle.

@Luna_Aberra 3 жыл бұрын

After 8 minutes of starring at this time I just gave up and watched more tips on how to solving Sudoku. I am still greenie in learn. And still many things I don't understand but thanks CTC for get me hooked. I love Sudoku now more than ever before and I think it's even my favorite kind of puzzle to do

@Piatato 3 жыл бұрын

Very proud with myself to have managed this in just under 30 minutes. I found it a very rewarding puzzle!

@Kelters 3 жыл бұрын

32:46 -- There's a fine line between logical tracing and bifurcation. However, I think my solve was logical. After studying it for a while it became clear I would have to work with pairs (or something like that) From a 27 pair in c5 I got to a solve. Difficult until you get a couple of digits, then the rest just follows like any Sudoku with that many digits already given on the board. -- (edit) now having watched Simon get that first 4 by a much better path from the 27, I see I could have been more logical after all! However, not disappointed either. And - Well done Simon!

@charlottegracedel9686 2 жыл бұрын

I have just recently begun playing hard level sudoku and have played this puzzle twice while watching your video. I must say it was fun!! You did an excellent job explaining how to solve it.

@roland1837 3 жыл бұрын

I found the swordfish on rows 1,5,9 with 2's because you have taught me to look for them... thanks Simon!

@Grikkez 3 жыл бұрын

Alternative solution path: Use slot machines on 2s and 7s. This gives a 156-triple in row 8. The rest is now easy.

@crazypomp927 3 жыл бұрын

I did the slot machine on 2s and 7s but don't see how that leads to 156 triple in row 8. Edit: I found the triple but it's not as simple as just doing the slot machines on 2s and 7s first. The slot machines don't give you any digits directly but allow you to rule out some 2s and 7s. This leaves only two positions for 2s in row 8, and combined with the given 4s in columns 3 and 4, you get a 2-4 pair in row 8. This eliminates a 7 from r8c5 and gives a 7 in r9c4, which unwinds all the 7s in the grid and leaves a 156 triple in row 8.

@FF_Fanatic 3 жыл бұрын

@@crazypomp927 The triple appears when you list per-cell candidates along the row. 3 cells can no longer be 2 or 7 and 156 are the only possibilities left.

@Grikkez 3 жыл бұрын

@@BremSterPuzzles Yes, I realize that using swordfishes would've been easier than using slot machines. I watched a video with slot machines earlier today and realized that all the offset clues were positioned perfectly for slot machines. I was so focused on slot machines that I didn't notice the sword fish patterns which emerged. (Still, even though the sword fish patterns are probably easier to spot, the slot machine patterns more immediately resolves all the 2s and 7s in a swoop after noticing the interactions in row 8.)

@Stratelier 3 жыл бұрын

Also found this solution path, practically by accident (I did purposely check all digits for swordfish, finding only 2's and 7's, then noticed the 156 set almost by coincidence).

@nigelm5777 3 жыл бұрын

As we might expect sudokuwiki rates this as gentle/easy because the hidden pairs are found on the first step, followed by nothing more difficult than hidden singles. Chalk this one up to the computer? Fascinating!

@namelessminionveinreaver3763 2 жыл бұрын

I wanted to try it myself before watching, and I didn't spot the hidden pairs. I Goodliffe'd and marked every cell in the grid before I started to catch on. That ended up being quite enjoyable. Every digit did a lot of work on other boxes, sort of like I was being lead around the grid.

@sergeyvoytsekhovskiy8373 Жыл бұрын

im sorry, what does Goodliffe-ing mean?

@namelessminionveinreaver3763 Жыл бұрын

@@sergeyvoytsekhovskiy8373 Mark Goodliffe, the other host of the channel, has a tendency to go overboard with the pencil marks, putting them in more than 2 corners of a box or putting more than 4 in a center, the standard method.

@sergeyvoytsekhovskiy8373 Жыл бұрын

@@namelessminionveinreaver3763 oh, i see, thank you!

@SamCoca 3 жыл бұрын

Great tip! I’m always going to look for hidden pairs from now on when I get stuck. Thank you for the great lesson.

@Zift_Ylrhavic_Resfear 3 жыл бұрын

I pencil marked every time there was 3 options in a box instead of 2 like you, and when i got to 8 i was getting a lot of these and i saw a lot of patterns like in the sudoku with 10 hidden swordfishes so i went to hunt for swordfishes. Found one on the 2 and 7, which got me the 27 pair you so easily spotted, which removed the pencil mark of 4 in box 8, unlocking the rest of the puzzle.

@joshpowell3650 3 жыл бұрын

25:38 for me just by filling in all the digits, finding a 2 and 7 swordfish, which created a 156 triple in row 8. Very satisfied with that :)

@skimeup 3 жыл бұрын

Fascinating to see him finding the hidden pairs. I noticed all the offsets but didn't know what to do with them. However, I found two swordfishes on 2 and it unrolled from there.

@itsachickenwiththing 3 жыл бұрын

It's always lovely to see a sudoku that solves itself once you can manage to put in the first digit. Like unfurling the ribbon on a christmas present.

@roccoberetti7066 3 жыл бұрын

you're possibly the first world puzzle solver's champion/ sudoku's champion who just came out and said 🤠🎸

@QemeH 3 жыл бұрын

Bloody Nora, I had to use half a shedload of colours to get my head around the opening - 51:40 [Edit: Watching the video, I'm once again reminded how much better Simon is at solving these than I am. He spotted the hidden 2/7 pair in what felt like seconds - I had to color the whole grid with all the options for 2's and 7's to come to that conclusion. But I have a small consolation price: I did spot the effect on 4's in the bottom three rows faster than Simon did. That's something, innit?] [[Edit 2: In case somebody is curious, because I know that some people are more visual types, here is how I managed to do it: First you realize that Boxes 4 and 6 have two possible placements for both the 2 and the 7. Then you pick colors for the options (e.g. green/red for the two options for 2 and blue/purple for the two options for 7) and run them around the grid. Every color option "finishes" the grid, so you'll have 6 squares of each color - with one little twist: two squares (the ones that will become the 27 pair later) have two colors at the same time - one is a 2 option and one a 7 option. This means, both of these colors can't be true at the same time; ruling out two of the four possible color pairings. You are left with the question which of these pairs is true. This is not resolvable at this stage - but because Boxes 2 and 8 have colors from two _different_ pairings in them, the double-colored squares absolutely _have_ to be part of the working pairing - which means they have to be 2 or 7. And that's how you get the 2/7 hidden pair...]]

@kristinbyers6275 3 жыл бұрын

I saw that pattern and the almost symmetry with those numbers but could not figure out what it meant. Thanks for a great demonstration! I learn so much here.

@Oszilgath 3 жыл бұрын

I didn´t recognize the pattern, but with "a few" more pencil marks, i was able to spot the two pairs and the 4 in c1. And at this point it got easy. But I´m still amazed by your skill solving this in about 15 minutes and explaining it simultanously. It took me about 38 minutes to solve it.

@ronaldkoh5281 2 жыл бұрын

Wow, I am totally enlightened. Brilliant. Pure logic without all the clustered numbering. Thank you very much.

@geo-fry6372 3 жыл бұрын

I solved it in 16:33. I basically just put in every pencil mark, and found 2 quadruples. The puzzle unwound itself from there. Now I'm going to see how Simon solved this. Edit: We followed the same solve path, except he used far fewer pencil marks.

@adamcrum1723 6 күн бұрын

Thanks, this helped me a bunch. Really appreciate you sharing this.

@antonyduhamel1166 2 жыл бұрын

I paused the video at 16:00 when I spotted the 4 before Simon did. Thinking I could manage this puzzle, I went into the link and gave it a go. My first attempt was horrible because, for some reason I will never fathom as long as I live, I pencilled in 2-7 into Row 2, Column 5 despite the fact that there was both a 2 and a 7 in that very row. So I restarted, using the logic that Simon had showed me and managed to finish the puzzle in 22:56. I'm not gunning for Simon's job or anything, but it felt good to get a puzzle done in roughly the same amount of time as someone like Simon, even if I did need 2 attempts.

@kaybrown8885 3 жыл бұрын

thank goodness for this video. I couldn't find the second hidden pair and caved to watch the video to that point and get going. Loved it, thank you!

@johnpinchard6261 3 жыл бұрын

I take a screen shot of the starting puzzle and load into Soduku+. Having pencil marked all two digits per box I then allowed myself to pencil mark three digits. The puzzle then seemed to solve easily (12 minutes) without any clever techniques. I am far from an expert so was pleased with the result.

@negar1368 3 жыл бұрын

I'm so proud of myself for solving this! Thank you CTC channel!

@hilcovanbreeschoten720 3 жыл бұрын

44 minutes. I found the pattern of possibilities on 2s and 7s very limiting, with a maximum of three possibilities per box. Also noticing how they were arranged such that the boxes are affected in a cyclic manner (for example placing the 2 in box 1 forces the 2 in box 3, forcing the 2 in box 6, forcing the 2 in box 4, forcing the 2 in box 1). Then I started to spot any contradictions (you could explain that as light bifurcation), and I found I could reduce the possibilities for 2s and 7s in each box to only two options. For every box that had three options, those options are arranged in an L-shape, and every time the corner of the L-shape could be eliminated. After this, i started noting all cells with only two possibilities and then especially paying attention to boxes, rows and columns where 2s and 7s were eliminating. Then I found a 156 triple in row 8, giving a 7 in r8c9 and that basically cracked the puzzle.

@dvdspndl 3 жыл бұрын

Nice one. I did it in like 15 minutes by finding the exact same 27 hidden pair in col5 and then the 4 etc. What made it a easier for me is something that you call a slot-machine but in fact there's a clear and simple pattern to it - it's sort of a generalization of an empty rectangle. I applied it to 2s and 7s, and then it was very easy to follow.

@danielcenteno8741 2 жыл бұрын

11:41 for me... One of those ones where it's just a blast to solve, no words other than such a fun classic sudoku.

@crazydaddy4934 3 жыл бұрын

8:36 for me - went about it starting with a pair of 27 in R5 leading me to a swordfish in 2 and 7, which I didn't even really need, as the 27 pair made R8C1 a hidden single 4, solving both swordfishes right away. From there it was smooth sailing :-)

@yura_riabov 3 жыл бұрын

Love those guitar intros🤩

@jrrothschild1090 3 жыл бұрын

Turn it up! 🙂

@claudiagreen9277 2 жыл бұрын

why is no one pointing out that his intro riff is "sweet home alabama" this is the best thing i've seen all day

@karadana11 3 жыл бұрын

First time commenting on your videos, after almost a year of isolation I managed to solve in 4.15 and its all thanks to you guys.Thanks for all the fun.

@LK-3000 2 жыл бұрын

I started out watching you solve it and then I just went on my own. I do like seeing your strategies, though. They are so different than my own and it's a beautiful learning experience.

@KinkyTurtle 3 жыл бұрын

I started out trying to do clever things like Simon does. Didn't get anywhere. Then I shrugged and just filled in ALL the possible digits. Spotted a lot of quadruples, triples and pairs that way!

@dooby78 3 жыл бұрын

Yup me too. It's the quadruples in columns 5 and 1 that give the first digit and blow open the puzzle.

@harstar12345 3 жыл бұрын

It certainly looks like a puzzle that is really tough unless you do that - but once you do it just falls away into simple eliminations. I don't think there's anything wrong with that, but it's certainly nice to find the logic like Simon did.

@elevendarter112 3 жыл бұрын

I stopped the video at about 1:10, drew my own sudoku, filled in all possible numbers and then gave up... There were 7 cells with only two numbers in them and I thought that it might be the key...then I was wondering how you would go on with that and watched the rest of the video. Wow! What a briliant solution.

@Arkanelancer 3 жыл бұрын

This was my first time actually completing a puzzle that you've done a video on. I solved it before watching, it took me 27:43 and I started out with a guess made after making some pencil marks. Some of that was because I'm not used to the controls, but most of it was just me struggling to place that first number. It does make me feel better that you also took a while to put the first number in, but watching your logic for this class sudoku was really compelling!

@lct9elliot66 3 жыл бұрын

guessing doesn't use your brain which is the whole point surely? anyway - good guess - mine are usually bad :(

@TafferBoyElvis Ай бұрын

I imagine some people wouldn't watch a video like this, but it was quite engaging. I saw the 2s and 4s fall into place in my mind while I was watching you talk about the other numbers.

@andrewzmorris 3 жыл бұрын

26:04 really really happy with my time. I didn't solve it exactly the same way as Simon - I first noticed the Swordfish on 2s and 7s which then revealed the hidden 2/7 pair in column 5.

@BryanLeeWilliams 3 жыл бұрын

Could we please have a video of just Simon playing guitar for 3 minutes? Kickstarter stretch goal maybe?

@rivercox8172 3 жыл бұрын

I have to say I love the guitar intros, keep it up! Love your videos!

@DNXTMaster 3 жыл бұрын

the "slot" technique on 2's and 7's coupled with a 2-4 pair in row 8 is what cracked the puzzle open for me

@MsNosis 3 жыл бұрын

solved it! freakin' solved it! used the swordfishes, and solved it! sooooo proud, now off to eat an entire bag of dried mango to celebrate!

@buzzly108 3 жыл бұрын

4:56 Let's get cracking!

@readersrock101 3 жыл бұрын

i watched this video because it was a short video that would help me relax before going to sleep, but this actually gave me some tips to help me with a hard puzzle ive been struggling with for days!! i can’t wait to revisit it tomorrow and use what i learned

@matthewender3473 3 жыл бұрын

Took me a good bit longer, after finding the hidden pairs, I worked out the implication of placing 7s and then 2s, which made a beautiful pattern of colors for the two possibilities but no conflicts. On the plus side, when the 4 did come, the whole thing snapped into place.

@harrysurtees8710 2 жыл бұрын

Yep, the 4's were the turning point, everything went smoothly after that.

@Xhopp3r 2 жыл бұрын

I have a classic sudoku app on my phone that I play almost daily. I always play on extreme. When I solve a puzzle in 8 minutes and I see I am only 30% above others, and then I see this video in which a very smart man solves the puzzle in roughly the same time, then I know the other 70% have cheated. Great job at solving this puzzle.

@sebastiandiel7538 Ай бұрын

I'm completely self-taught and don't know the techniques named in the comments or the video by name. I do pencil markings differently (perhaps less efficient): whenever I make a mark I write all possible numbers in the cell, subsequently taking them out again. I restrict myself to three, normally. With this beast I had to make it four. It took me some time, but then I found the 27 pair by spotting the "negative" of it (1459) in the central column. Next I found 359 in row four and 1458 in row 6. My first secure digit was the same 4 as well. So this might actually be the single key to the maze. Seeing no fun in brute force methods, I have made an Excel VBA sheet to analyze Sudokus step-by-step, I've just checked: it solves the thing as well (also with that 4 as a first success) . It does not do any bifurcation, you just select normal Sudoku rules (look for sets in rows, look for singles in squares etc.), always one at a time, to see the progress. Is anyone interested in such a tool?

@djmitt3807 3 жыл бұрын

OMG!! Your intro "Sweet Home Alabama" by one of the best (if not THE best) Southern Rock Bands Ever !! Lynyrd Skynyrd

@barborasharrock1938 3 жыл бұрын

I was expecting the piano intro, and instead it was your guitar playing! So cool! Man of many skills

@MrBenzt0wn 3 жыл бұрын

What is elegant about the puzzle is that we have the digits 1-9 in boxes 3, 6 and 9 and also in 1, 4 and 7. In 1,4,7 even in correct order from top to bottom.

@bighouse1695 3 жыл бұрын

Hidden pairs and the extra numbers it eliminated were the whole 🔑. Brilliant job!

@danielrhymer1762 3 жыл бұрын

13:07 for me. Used colours to work out the possible positions for the 2’s and 7’s and realised there was a 27 pair n column 5. From that I got the 4 in box 7 which solved the 2’s and the rest dropped out easily.

@kaiwienbeck8598 3 жыл бұрын

so did i, not hanging around what could have been there too, if you find such a pair also the solution must to be find there! because once the sudoku must have been constructed as a puzzle!

@Lumosed 3 ай бұрын

17:57 I used the 3/7 and 2/7 hidden pair along with one 6/8 pair in the first row And i used phistomefel's ring to place and 8 in the middle box

@piarittersporn 2 жыл бұрын

It was a bit confusing at first, but after finding triplets and quadruplets in my pencil marks and thereby being able to reduce some other pencil marks, it went a lot quicker than I thought. I really enjoyed this puzzle.

@ib9rt 3 жыл бұрын

I haven't watched your solve yet, but for me the key was a couple of hidden pairs, then two overlapping swordfishes, then Snyder notation did the rest.

@qivarebil2149 3 жыл бұрын

I found the 4 in column 7, row 6 first. Relatively simple from there. My method is focusing on the numbers from 3 to 7 only. I don't like doing the pencil marks. Makes me feel unfocused. I just need to have all cells in the count all the time. While memorizing the known numbers, I delete them from my sight - just staring and staring at the sheet until they disappear, and then it's easier to imagine where the missing 3s to 7s go. I guess it's just a concentration exercise. Focus, focus, focus - and then suddenly, light! 2 years since I had to give up a 9 cell. But when they come like this one, they always leave me in physical pain, though. Sometimes for hours! I could never solve this one, while at the same time explaining it on video. I need to be extremely quiet, and don't tolerate any noises around me, But You did very well, Simon!