Diabolical Sudoku: One Of Our Best Solves?

[@samb5017]

@15:44 you know it's a weird puzzle when he says "this is a 1 by normal sudoku rules" on a normal sudoku

[@letMeSayThatInIrish]

Good observation. I didn't even notice because I was totally onboard with this not feeling like a normal sudoku.

[@autodisplay2831]

This solve is brilliant. Without going into any crazy strategies you somehow find amazing logic that even I manage to follow.

[@aniketb2010]

#MeToo ;)

[@OwningLuukjuh]

After 15 minutes of trying with no digits and blindly staring after filling every 2-possibilities, I simply thought: "Ugh, just take it from here Simon, I give up"

[@Blubb5000]

This was actually super easy. No advanced solving techniques needed at all. Just just simple logic. Very cool puzzle!

[@jackdog06]

"this part of the pattern is screaming either x-wing or swordfish at me" ...y-yeah... me too.... obviously... totally.... ...what?

[@rabidsamfan]

21 minutes, and it felt really good when the puzzle started to just fall apart. I would love to see more like this!

[@martinpolach6171]

I enjoyed the comment ..”No Brute Force” ....Simon’s approach is so eloquent and satisfying ....the true essence of the game!

[@tananari47]

I did this puzzle, before watching... took you about fifteen minutes, took me over two hours. And I consider myself pretty good. So. Yeah. I won't be dissing your abilities any time soon.

[@blandingswest6560]

Surprisingly this puzzle rates only as _Tough_. No techniques more advanced than hidden subsets are used. Yet Simon's solution is one of the most elegant on the site: a series of masterstrokes without the slightest hint of brute force.

[@austinjensen2957]

Just casually solves it in less than 20 minutes without guessing. There is no way I could have solved it without guessing. Took me hours to solve with guessing. Simon you are so fast at making progress it blows my mind.

[@williamwester9203]

Going back to some early puzzles. Proud I got to the solution. I got to the solution by considering the 5 and 6 restrictions along the edges and using the cells 2, 4, 6, and 8 and considered "empty rectangles" on 5's and 6's in those cells. I don't usually use "empty rectangles" so I was happy it worked out.

[@mmanes100]

Man, you are from the another world!! Greats from Brasil.

[@shane8037]

12:29 when Morpheus tells Simon that when the time comes, he won't have to apply normal sudoku rules

[@gposchman]

Monster puzzle, maybe evil, did okay but had difficulty until I went back to making notations, and found my error. A lot of fun, a good 90 min of play for me.

[@bananafarmer7555]

Working my way through the puzzles chronologically. Managed to do this one using different opening logic to Simon so very chuffed with myself.

[@eireannsg]

17:46, two times 1 in row 4, exactly what happens to me all the time.

[@antoninmasson7354]

Hello, i have a question at 12:40, why can't it be a one ? I don't understand why the 1 and 3 can only be in column 3

[@Martykun36]

By checking column 3, first he noticed that 7 and 8 form a pair on rows 3 and 8. Since that restricts row 8, rows 4 and 5 form a 1-3 pair.

[@antoninmasson7354]

@@Martykun36 Thanks, I'm a beginner in sudoku and sometimes it's hard to follow everything. Thanks a lot.

[@Questerer]

After watching these videos since may I finally started to dust off some old sudoku books I had laying around. They are challenging but not really hard. It takes me hours to complete one. And then I watch this video with an amazingly hard puzzle. Solved in about 15 minutes. I still have a lot to learn.

[@timsullivan4566]

Well done spotting the 4 #s in both side cubes also in top and bottom rows. From there it all unfolded nicely.

[@grahamfisher307]

After 12 mins, having seen the 1 & 3 pair placed in block 4, using uniqueness to restrict where those numbers can go in block 5, I determined that the only place for 9 in the central row was R5C7, which fixed the 7 in R4C7.

[@murphy9453]

Is there an app for iPads that allows you to have both a corner and center option for notations? I have looked but then unable to find it.

[@lightningt12312]

Really smart solve using the symmetries.

[@murphy9453]

Is there an app for iPads that allows you to use both corner notation and center notations? I have looked but have been unable to find it.

[@yiotatort]

didn't do half as well. though watching through yours I was able to figure out where I went wrong

[@aniketb2010]

The 2-5-6 triple in the middle row did the job after the 1-3-4-8 and 7-8-9 verticals. Honestly I couldn’t figure out the 4 referring to the triple for almost 2 hours. Stupid on my part!! Thanks!! 🙏🏼

[@matthewcooke4011]

I spent absolutely ages making a whole array of pencil marks all over the grid, without solving a single number. Eventually, I tested/guessed one digit (50/50 between 5 and 6 in the middle of the bottom row) and the entire puzzle followed easily from there, correctly luckily.

[@dvdiseased]

I don't understand his logic for the 2's at 9:47, couldn't the 2 in box 6 also be where the 9's are?

[@perine100]

Where are these links “under the video” that is always mentioned?

[@1981stonemonkey]

I like how every intro starts with a text colour arrangement that resembles the Dutch flag. Groeten van een Nederlander!

[@wittesend]

I’m not sure where I’ve been, but I just discovered your series. Been doing sudoku a fairly long time and love seeing (and hearing) your logic. Thanks for explaining so well. One small question: Will your sandwich sudoku app work on an iPad?

[@edwinvanderburgt]

I have the Sudokupad-app on my iPhone, but how do I get this puzzle into the app? If I click the link, it just goes to the web-app without asking to open it in the app itself. And if I choose 'import puzzle' in the app, I need a puzzle link that ik can't seem to find anywhere. Any help is really appreciated. Thanks!

[@lifesnotfair]

This is a MONSTER of a puzzle! You needed to identify a quadruple before putting in the first digit. As I am printing these out and using a pen, I am not using that second method of notation (numbers in the center of the cell). Am I right in thinking the 'diabolical' puzzles actually require this other method? I don't see how you could have done this using your traditional method of pencil marks alone. I will swallow my pride and go back to 'expert' level for the next couple of ones. Then maybe I have to download the App and try a diabolical one with all the notations. Still I'm not sure I could have gotten this one though! Must keep practising. As always, a joy watching you conquer it.

[@AWildBard]

I couldn't have done it without watching this video. Seemed almost simple and obvious when I watched, hahaha Very fun

[@davidbeaumier4953]

Made one mistake giving me two 2. Then had to "try" the first square of the seventh column and everything break down... One the one hand, it work. But i couldn't find any logic to get me going and had to resort to guesswork... I still have a lot to learn...

[@ratchet1freak]

I looked at where the 5s could go by filling in each of the cells on one edge with a 5 and chaining it forward, found a rather restrictive pattern with them, then I bifurcated with a 6 in r5c1 and solved the entire thing from there.

[@willis49er]

I had a similar approach but failed when the puzzle became clouded with non-Schnieder notations (I think that's why)

[@javabeanz8549]

One of the first things I noticed was there were only one 6 and NO 5's anywhere in the placed numbers.

[@Czeckie]

It's interesting since there was no fancy technique used, not even an X-wing. Sudokuwiki.org solves it just by using the simple strategies. Yet somehow it's complicated for us humans.

[@nigelm5777]

Yes, Sudokuwiki.org finds the same quad as Simon in its first step. The genius was to see a hidden quad without filling in every dang candidate. The solvers second step was to find the triple in row 5.

[@dagg310]

at the beginning he put 1348 in the 9th box but there was already a 4 in that box and also in the 8th row. there's also an 8 in the third box and a 3 in the second row

[@AndersAstrand]

I spent 25 minutes on it without getting a single digit in 😅

[@dennisted836]

I feel you bro... 😂 😂

[@ponsantosh1648]

I still cant understand why at 9:24 the three cells have to be a 256 triple pair? Anyone who can dumb it down for me?

[@blingblingjonghyun7473]

The central marks Simon uses mean, the cells can't have any other number than the marked ones. For example the 5,6 in r5c1 can never contain anything but 5 or 6. The same goes for the other two cells in this row he marked. So if you now try to put e.g. a 5 in any other cell in this row, it wohl make r5c6 a 6, r5c9 a 2 and nothing would be left for r5c8 or you'd have to repeat a digit. The same goes if you put a 2 or a 6 in any other cell but the marked ones in this row, only with slightly different outcomes of the exact numbers. The result remains the same though: you will have not enough numbers to fill the cells without using one of them twice. So the conclusion is: Those form a pair. Hope this helps :)

[@fpupesh]

I stared at it for 5 mins then I started marking tipples and quadruples. Then I thought - I think i'm going mad here, this can't be right, played the video and I was laughing like crazy... I guess I went the odd road as well just didn't go all the way :D

[@stevenape377]

It seems that the puzzle pretty much requires identifying that quadruple (if you don't want to bifurcate) - which is the first thing you did! How did you know??!

[@jonahkoehlert8747]

just over 30 minutes to solve this one for me but i used a bunch of help from simon. Really tough puzzle in my opinion

[@fossil98]

12:26 Why couldn't that square be a 1?

[@MinhNguyen-fi6xz]

Because 1 and 3 are locked in the 2 cells to the right

[@malcolmbacchus421]

App still doesn't work on my iPad, I get the grid and buttons, but pressing the buttons does nothing at all - apart from changing their colour to grey.

[@CrackingTheCryptic]

That is really weird as I often use the app to solve on my ipad and it seems ok. Let me ask Sam.

[@nigelm5777]

Malcolm Bacchus - no problem on my iPad.

[@paulvanegeren1227]

My old iPAD has the same problem Malcolm has (A6 chip, iOS 10.3.3, 3rd generation iPAD I think) but my newer iPAD works fine (5th generation, A9 chip, iOS 12.4.1).

[@lesternielson9280]

Great Puzzle!

[@Moonwired]

Those fours pencil marked in box 9 triggered me so much

[@leojf3828]

I can follow along but i don't find these on my own. *MORE practice*

[@Monkey2001Crazy]

@17:13 why did he decide that box was a 9?

[@riccardocampagna8546]

That row is missing 2, 4 and 9. Since 2 and 4 are already present in column six, that cell must be a 9.

[@Monkey2001Crazy]

​@@riccardocampagna8546 Oh I get it now. Thank you!

[@tglrod]

You are a genius!

[@alekom6122]

gosh, after 13:25 he realize the 8 in the right upper corner!

[@glennmelven3414]

I made a mistake with the 56s on my first attempt. 2nd attempt went much better. 21 minutes

[@scottframe7809]

Finally a puzzle i was actually good at. we think so differently i got this with ease. I guess that just means my brain is as dumb as a computer.

[@PuffyOne1898]

ok, something's bothering me. How did you rule out that a 4 can't go in the bottom right block of the top left box? Furthermore, how did you rule out that a 1 can't go in the bottom right block of the top right box?

[@sthurston2]

I agree - What just happened! WHY! So after going back over it ... >> ok, something's bothering me. How did you rule out that a 4 can't go in the bottom right block of the top left box? 11:45 r3c3={78} because in column 3 only that cell and r8c3 can be 7 or 8. That is because of the 7's & 8's in the block to the right and the one below, and the already occupied cells. >> Furthermore, how did you rule out that a 1 can't go in the bottom right block of the top right box? 13:33 The {38} pair in the bottom right block mean the {35} is a 5. That and the 2 in the bottom left mean the {125} in bottom right block is a 1. That excludes the 1 from the {125} in the top left block. I have only just recently discovered Cracking The Cryptic. Learning loads and loving the beautiful normal Sudoku puzzles - great practice even after watching the solution.

[@brucerose4383]

Did anyone notice there is a slot machine on 1's? Sorry, if this is already discussed .. I couldn't tell if it bore fruit .. i.e. the slot machine process ..

[@miroslavapaleckova838]

44:44 :-D. Nice sudoku.

[@bailwrittepapichulo5623]

I dont think the posters will answer but I'm only halfway thru the video and he had 1348 in the top right box as options but there's clearly an 8 in that box so how is it possible for an 8 to be in those cells. Makes no sense

[@EyeDewDie]

I figured out the 7,8 from column 3 before he did. I feel so smart for noticing it.

[@TheGreatGritzy]

28:43 Feel proud on this one!

[@hess4win725]

@crackingthecryptic I noticed your 1348 quadruple which appeared to be an early crucible for the puzzle ended up not being valid because of the 8 in the intersection of the first row last column. Instead the quadruple turned out to be a pair of 13 and 48 cells. I'm trying to figure out if the logic from the quadruple is different from the pairs to effect the solve. Was it luck or did the logic hold enough despite the quadruple becoming two pairs? I think its the latter since the two pairs still limited the contents of the cells. Was wondering if you had any thoughts.

[@DeltaGrab]

Why didn't u start off with pencil marking?

[@eamonal-saffar2861]

I actually solved it finding a jellyfish of 1's... made this one overly complicated

[@user-A168]

BEST!

[@kaiwienbeck8598]

1 und 3 dürfen im mittleren quadrat nicht untereinander stehen, dies kann man nutzen!

[@insectbah]

oof I got the 1348 quadruple and made a lot of pencil marks and then had to defer to Simon

[@ShardyRedVH]

3:05 Oy vey! I didn't spot the 4 in box 4 and so it really dragged out the puzzle for me.

[@jmadratz]

When you put in the 1348 quadruple at the start, the upper right quadrant already has an 8 so why did you say those squares in that quadrant that you put 1348 could be an 8, it cant be an 8. Similar comment for the lower right quadrant. The 1348 and only be 138 since that quad already has a 4. If you agree with this, than the 9 you filled in the lower right quadrant would only be a guess.

[@MemoriesLP]

I think the 4 and the 8 would not change it, since those places can ONLY have 1,3,4,8. Since 8 and 4 cant be used, then there can be ONLY 1,3,4 and 1,3,8 9 still needs to go there anyway. Not a guess Correct me if Im wrong

[@Lyndalewinder]

Wow what's wrong with your microphone?

[@aut_zero_0120]

Beast

[@ValeriePallaoro]

hahahaha talking about patterns .. not in the numbers but all the spaces. Ohmygiddyaunt!! But then ... 1348 in the box that has the 8&3 in the row?? (*sad*) Ok. done talkin' Watchin' now.

[@SuperKagey1]

pretty sure you cheated on this one: @5:43 you incorrectly find four squares with the same numbers to deduce where a "9" goes. Then @9:35 you force a "2" in a square that could have logically gone in many other squares. with these squares correctly locked, the rest works - but the logic to get here was quite dodgey.

[@dvdiseased]

If a column has 4 squares where only a 1348 can go, you can deduce a 9 can't go in any of them, so in the bottom right box a 9 can only go in column 8, row 7, because only a 134 or 8 can go in column 7, row 7 and column 7, row 8. Im still trying to figure out how he got the 2 though. Something about a 3 number triple that I don't understand yet.

[@Socrates...]

I could not follow your logic because at some points you jumped ahead without explanation and placed numbers. Well done with the solve anyway.

[@wowwee8562]

Socrates I watched the same video had no problem, don’t understand what you mean there bro

[@shane8037]

@@wowwee8562 it's almost like different people have different levels of sudoku experience 🤔

[@Qazqi]

Which parts need more explanation? I doubt he's going to be able to help with that if you keep it as vague as "some points".

[@eireannsg]

17:20 you yet again overlooked something in a column. Column 5 has a 2. solves the 2,4 in row 6

[@ValeriePallaoro]

Yes, but it's easy to understand; for all the excellence of the solve, it did make him a bit giddy and he can't follow your eyes

[@ValeriePallaoro]

I say this ... cause I sit here (hours after the solve) and go ... why don't you fix this first, cause ti's right out there in the open and he gets to it, like, 20 moves later

[@sthurston2]

Nice to know I am not the only one shouting at the screen. I have been likewise temporarily blind many times.

[@johnjacobjinglehimerschmid3555]

ok.... I can't understand the logic you used to make the first 9 in the lower right neighborhood? Someone able to shine a light on my ignorance? He just says oh yeah 1348 in these 4 cells ..... and I'm like no 3 or 8 in the top right grp and no 4 in the bottom right grp cells. Then oh yeah that makes this a 9 .... How did he eliminate that that cell could be a value of 2359? Ok watched more and you know what you're doing ..... but I'm not following your logic. You said you had a triple in the middle row 256 .... yet it's 56,256,25 ... then you said seeing how 2 can't be in the 3x3 grp on the right in the middle row it must be in the bottom. I don't follow how you can say that the bottom cell in col 7 can be 2. It solves the puzzle just can't follow. 1031

[@Chimel31]

Took me a while too, but it's very logical, based on the rule that every digit should be present in every line, every column and every block. Since the digits 1, 3, 4 and 8 are already in block 6, they will need to be somewhere in block 3 and 9 too, as well as in column 7. These 4 digits are already in rows 1 and 9, and they can't be in rows 4, 5 and 6 because they are already in block 6, so in column 7, they can only be present in rows 2, 3, 7 and 8. There are 4 digits for 4 possible locations, so we know for certain that these 4 locations contain one of these 4 digits, we just don't know in which order. Now, regarding digit 9, there are already two 9s in rows 8 and 9, and a 9 in column 9, so the digit 9 for row 7 can only go in columns 7 or 8. Since we know row 7 column 7 can only contain 1, 3, 4, or 8, the only candidate left for digit 9 is row 7 column 8.

[@catman1353]

I don't like Sam

[@peterjongsma2754]

You have a lot of adds. Must be successful at making money. You think very fast. Slow down.