Another Familiar Phenomenon!

[@greg_loper]

Thanks for being willing to show the error. Much appreciated seeing both it and how you recovered.

[@Kairamek]

That's some real good advise Mark. You guys keep using superlatives to describe puzzles, but when I finish one, all I can say is "That was fun. I had a great time solving it."

[@alanclarke4646]

Same here, and this one WAS fun!

[@renardor]

I usually try the puzzles to have fun. But when i read the rules of this one. I realized how clever Aad van de Wetering is. To be this consistent for the entirety of the puzzle is flabbergasting ! Congratulations are in order for this one particularly.

[@boydegg]

17:20 .... What a brilliant and original puzzle idea. Love it!!!

[@muskyoxes]

Working out all possibilities down the diagonals when starting out with 3478 seemed like such a fool's errand, yet it narrowed down swiftly

[@rmjarvis]

That was exactly my thought too. I was like, I might as well try it and see how long before it blows up to include all digits, but it was actually very constrained.

[@noahboss9618]

Aad is such a genius. Wonderful puzzle!

[@inspiringsand123]

Rules: 02:27 Let's Get Cracking: 04:43 Mark's time: 19m09s Puzzle Solved: 23:52 And how about this video's Simarkisms?! By Sudoku: 4x (21:25, 21:35, 21:48, 23:33) Ah: 4x (13:53, 14:43, 17:19, 19:22) Weird: 4x (08:16, 08:53, 08:56, 15:08) Sorry: 3x (07:35, 14:04, 18:45) Naked Single: 3x (21:52, 22:43, 22:54) Brilliant: 3x (01:08, 01:46, 01:51) Incredible: 3x (00:26, 15:34, 24:53) Pencil Mark/mark: 3x (05:03, 06:26, 15:11) Goodness: 2x (13:57, 23:48) Bother: 2x (12:08, 18:24) Deadly Pattern: 2x (23:03, 23:11) Obviously: 2x (01:54, 22:19) Intriguing: 2x (03:15, 20:28) Wow: 2x (14:34, 18:35) Clever: 1x (23:55) Fascinating: 1x (24:25) Extraordinary: 1x (24:32) Astonishing: 1x (03:26) Hang On: 1x (08:20) Bizarre: 1x (23:51) Surely: 1x (04:53) In Fact: 1x (07:45) Progress: 1x (11:12) *****ing: 1x (15:32) Most popular number(>9), digit and colour this video: Thirty Seven (6 mentions) Two (59 mentions) Blue (2 mentions) Antithesis Battles: Low (8) - High (4) Odd (2) - Even (1) Row (3) - Column (3) FAQ: Q1: You missed something! A1: That could very well be the case! Human speech can be hard to understand for computers like me! Point out the ones that I missed and maybe I'll learn! Q2: Can you do this for another channel? A2: I've been thinking about that and wrote some code to make that possible. Let me know which channel you think would be a good fit!

[@Aliessil]

Wow, finished in 10:01 - think I got lucky without making any (very easy!) mis-steps. That was an amazing puzzle! o.O

[@aidancurry997]

At 16:19 is that another error? Couldn’t 5 go up to 9?

[@IgorPellinen]

yep, I wouldn't count this as a solve unfortunately

[@chocolateboy300]

I finished in 22:23 minutes. I, initially, thought that the neighboring rule only applied to those on either side of the line and the line. I already thought it was impressive to make a puzzle like that, but then I reread the rules while solving and saw that it was every parallel line. That made it even more impressive that this puzzle exists. Aad does a fantastic job at showcasing puzzles like these. It took my brain a bit of time to catch up to the difference, but once I did, the puzzle flew. I had a fun time with this one. Great Puzzle!

[@BrianStewart126]

I instantly got the main diagonal and 6 in box 7, then proceeded to mark options on the other diagonals but figured I must have been missing something fundamental. I checked the video and saw you starting down that same approach, so I persisted and filled out everything along those diagonals coming off of box 7 and was amazed that it all just fell into place.

[@blomster4304]

Kinda happy to see that Marks streak of guessing digits correctly based on reasoning mistakes ended

[@MarkWiseTechno]

20:12 Brilliant setup, lovely solve!

[@zachx4338]

Was able to get the middle line almost instantly, but was stuck on what to do next till you brought up the 6 in the corner being the only place it could be. That led me down a path of "what if's and the two lines beside the middle one lining up "too" well before it all just came together. Crazy how one little clue/step was all it took to hold back the rest of the dominos. Decided to watch the rest of your solve, and right as you said you might have whole puzzle now at about 15:35, I was like "I SAID THE SAME THING!!", wonderful when the logic works. Wonderful puzzle, thank you for sharing!

[@bristolrovers27]

Another brilliant puzzle by Aad, what a surprise lol, the man's a flaming genius

[@scarletmanuka6170]

21:10 for me. I really liked the start of this one, and the rest was pretty straightforward. It's amazing to me that you can get a valid sudoku fill with this ruleset, but it's not amazing that Aad van de Wetering was the one to bring it to us!

[@Kirbyfan87827]

Finished in 17:14. It was a lot to take in at first, but it got easy over time. Fantastic puzzle! I always love days when I can do both Simon's and Mark's sudokus!

[@lroke2947]

I hadn't fastened my seat belt when beast mode came on and will now have to rewind to see what actually happened when I said, 'what did I miss'. And that's, children, why you need to wear your seatbelt for the entire duration of the ride.😀

[@Liam-jn6zu]

Great job, Mark!

[@raysouth1952]

What an amazing puzzle! Loved it.

[@RobertLeyland]

13:39, with one misstep. The lead diagonal came immediately, but it took a few trials to realize that all the positive diagonals had the same pattern. Once that’s sorted it was filling in! Very cute puzzle.

[@annikaQED]

What a magical sudoku! Or maybe I should say, a "miracle"! It was dazzling how easily it unfolded. And note that every positive diagonal had distinct entries!

[@stevefaber1]

I'm not even in the same room as you, Mark, let alone the same league, but this time and for the first time ever I solved it faster (16:10)!! We started int he same way, but I saw the constant diagonal pattern whereas you went (almost certainly more sensibly...) for solving by Sudoku sooner than me. If you hadn't put a 1 instead of a 9 in box 3, I'm sure you would have finished faster than me , as ever. I really enjoyed both the puzzle and seeing you work out how to correct a mistake, which should eb helpful to me in the future. I remain in awe of your skills!!

[@DavidZennaro]

That was fun. I wonder why nobody commented on the fact that the diagonal was the same. What a wonderful puzzle!

[@peterhaagen8506]

The best puzzle for me a simple rule set and a lot of fun. 🥰

[@George4943]

What a nice one. Simply fun!

[@benjaminrealy5661]

19:23. Frustrating at first, but once rhythm got going, knowing the possible diagonals from any completed cell became easier. Lovely puzzle

[@easternbrown]

Funny how some puzzles are not that hard as such but are somehow easy to make a logical mistake with. Makes for a good solve.

[@RichSmith77]

This is a Deja Vu because its almost identical to one Simon solves back in 2022, called "A Sudoku With Only 2 Given Digits" kzbin.info/www/bejne/rYbRn4utgbmVpKMsi=6KA72lvm4v90nMX1 The solution grid is identical too.

[@thebitterfig9903]

What a gorgeous little solve. I wasn't particularly quick, but such a lovely pattern.

[@Jessicaaljp]

The 4/5 difference made my head spin 😂

[@opossum4722]

Loved the video!

[@Gonzalo_Garcia_]

8:45 for me. Interesting puzzle!

[@davidh.4944]

41:37@#585. I had to work slowly and carefully, placing and removing candidates, but in the end it all shook out nicely. A weirdly clever one.

[@TurquoizeGoldscraper]

31:29 for me - it took me a while to get the rules, and I kept forgetting that 9 wasn't stuck to 5, and that it could go to 4.

[@falloutfan2502]

Great puzzle! Not too difficult (good for me!) and yet fun to work through!

[@TheErsdot]

Appreciate you showing the error. I made the same mistake myself forgetting that the 5 can go high or low. Great puzzle

[@piarittersporn]

Very interesting and approachable puzzle.

[@joekerr3638]

If you insist...I forgive you Mark. Seriously though, you spotted the error remarkably quickly.

[@praematura]

Wow. Wow wow wow. That was a stunning puzzle! I'm amazed at how well it flowed for me, things just clicked, and was able to finish in just 6:50 (conflict checker off)! Many, many thanks to Aad for this, I loved it! What an amazing construction.

[@dolf370]

I got stuck on the 3478 in the box, had to peek a little bit on Mark, and realized my error was that I didn't take one digit at a time to investigate the diagonal but tried to figure with all 4 digits simultaneously . But when I followed Mark's way of trying a digit at a time I found there was a 2-7 pair in the box 5 , so actually solved it easier from there on. However, still took me over an hour, so I am clearly not up to Mark's ability. Loved the puzzle.

[@bobolek10]

Finished in 10:03, suprised that it went that smoothly

[@isidornimages]

FInished in 38.51, which I'm happy with. The start was easy enough with the blue diagonal and the 6 in box 7. Then I struggled until realizing I really had to bookmark everything that was possible and from there it flowed reasonable well, even though some of the bookmarks I had made in box 3 was wrong.

[@brucejones533]

I make lots of errors, I lack your patience in rewinding, I usually just start over. Fun solve, thanks!

[@craigyoung8008]

This puzzle looks *very* familiar. I’m have the feeling I watched Simon solve this a few years ago. Then again… the puzzle is called *Deja Vu* 😂

[@Paolo_De_Leva]

I cannot solve this tonight, but I have already figured out the logic in *box 7* and that is enough for me to say this is undoubtedly another *cosmic class* construction by Aad. Thank you Mark for featuring this stratospherically gorgeous beauty.

[@huxflax]

I usually don't press like until I've solved the puzzle. But I had to give it the thumbs-up number 667, well just because... 😂😂

[@rowanbrown5541]

Didn't catch either of the real mistakes. But the 1 being next to a 7 in box 5 was screaming at me and you resolved without ever noticing

[@andreaswestermoen4592]

cant see it mentioned, but if you let the grid wrap around itself (like a torus), all the diagonals complete the same pattern. (how long until we get a rubik's cube sudkou? )

[@zedaye9552]

8:36 solve time for me. Don't post many times up, but this has got to be one of my fastest solves (i generally dont care for the time, just enjoy doing them) Also, these type of puzzles, usually theres a whole lot of roping which hasn't been mentioned yet.

[@emilywilliams3237]

I am definitely trying this puzzle as soon as I have a moment - it looked like fun when you solved it, Mark, and the thinking required was elegant and not onerous. Thanks for featuring yet another great Aad puzzle!

[@moccoX]

00:10:02 for me :) towards the end I realised, that in miracle the order of the diagonale is always the same 😅. Couldve saved a lot of time there

[@whelmking6497]

Interesting and fun. 13:00.

[@bait6652]

Interesting, thought after the 5 main diagonals one could sudoku the rest but B12 requires the ruleset. Now is that design unique w/o givens??

[@ammonke6324]

I went at this the same way as a German Whispers puzzle; where do the 4 and 6 go? Realized pretty quickly that the 4 would have to be at the beginning of the purple/yellow diagonal in box 7, and that forced the same pattern as the blue line all the way up, effectively placing a 2 and 7 in box 5 regardless what color that 4 was on. By chance, I left the 48 on purple while working things out, put a 37 pair on yellow, 378 in box 4, and that's where it broke. 348 are already in box 5, and 27 are already on the other diagonal, meaning I lost the 50/50 and that the 48 actually belonged on yellow. I'm no good at finding naked singles though 🙃so it still took me about 11 minutes to finish.

[@drengskap]

It's indeed difficult to see how this could be solved without extensive pencil-marking.

[@vivim29]

I did not make a mistake but I was waaay slower, thanks for the vid.

[@QuLogic]

Wow, finished in 15:59; not usual that I beat Mark or the video length.

[@allanfiddler]

00:00:00 for me. Love it when the timer doesn't work as it makes me look good!!!😆

[@NitschLorand]

Amazingly the 4/5 rule applies even if you make a cylinder out of it, joining the right side to the left side.

[@Ferrindel]

12:53 You could also come down to 2 here, couldn't you?

[@geoff544]

Which he spots later as it breaks box 5. But I don't get the 'this isn't allowed to be 6 by sudoku' comment at 21:35?

[@RichSmith77]

​@geoff544It leaves nowhere 6 in row 4, but I had to pause the video to spot that as a "sudoku reason". Far simpler to just see 9 cannot descend to 6 or 7. Or to use sudoku as the reason to rule out 7 - maybe he misspoke and meant 7 was ruled out by sudoku?

[@Paolo_De_Leva]

Mark's break-in is too intricate in this case, in my opinion. You do not need to pencilmark so much. @6:17, after _"populating"_ the blue line, if you keep focusing on *box 7,* you can easily solve it: 🔹Elementary case testing allows you to rule *4* out of both *r7c2* and *r8c3...* 🔹Hence, one of the *8-cell* diagonals will start with *4* in *box 7* and will contain the following sequence, that you can center-pencilmark in boxes *7, 5* and *3:* *4 8 3 7 2 6 1 5* 🔹Now, by elementary case testing, you can also rule *3* out of both *r7c2* and *r8c3...* The *7-cell* diagonals are less restricted than the *8-cell* ones, that are immediately above and immediately below the *blue line.* It is not convenient to pencilmark them immediately, as Mark did.

[@Paolo_De_Leva]

Of course, as usual, my purpose is not criticizing Mark, but providing an alternative and definitely more straighforward approach to break in this puzzle. Mark typically solves with great elegance, and in this case he *skillfully* corrected his initial mistakes due to intricate pencilmarking, and solved much faster than I did. I always eagerly search the description section for alternative solving paths or deeper *meta-logic* analyses. I believe that's a very instructive excercise, and I assume others do the same as eagerly as I do.

[@fuxpremier]

8:47 for my time. An oddity for sure! Setting this particular grid and making it solvable is quite an achievement for sure.

[@Music--ng8cd]

Funny how a difference of 4 or 5 leads to the same repeating pattern of digits from lower left to upper right along each diagonal.

[@RoderickEtheria]

Along the rows, the pattern changes, but along the diagonals, the pattern is firm.

[@studgerbil9081]

even better, there are no repeats on any of the diagonals.

[@RoderickEtheria]

@studgerbil9081 That's a given by the pattern being firm.

[@SkillZgetKillZ]

I got 20:36 it is so much easier of a puzzle than it first seems

[@anninithepannini2684]

lovely

[@srwapo]

≈28 minutes. I broke it twice, restarted once, looked at the video a second time and saw I mistyped a pencil mark. Got there in the end. Not THAT hard, but my brain struggled with it.

[@danecarter5454]

Why couldn’t r3c8 be a 9 at the point Mark filled it?

[@danecarter5454]

Ahh, he sees it at the 19.20 mark

[@RandomNameofDoom1]

Thanks for getting it wrong a few times, I did manage to complete the puzzle, but I did also take a couple of wrong turns.

[@LednacekZ]

8:43 for me. the start was interesting but not hard.

[@DomODriscoll-d1s]

All the positive diagonals had the same rule set...no repeats

[@wanderlustwarrior]

I made so many mistakes and had to restart so many times... Clearly I'm not thinking well today.

[@srishti81388]

12:00 for me

[@philipgill4024]

easy to work out once you can see it's a repeating diagonal string

[@empathogen75]

Finished this one in less than ten minutes, and “solved” it in less than a minute. It’s pretty obvious that the pattern will always repeat. Once you fill in the two given rows, the rest of it is just looking for where the conflict is. I’m not sure I logically deduced that though. Just that there was no way the puzzle had a unique solution with so few given digits, _unless_ that was true. Usually miracle puzzles have shifted patterns like that, it’s the only way they can solve.

[@brianjrobinson]

16:55. First time I've bettered your time.

[@neversayxever]

Am i the only one to add "at least" to the rules myself? What a waste of time 😪

[@alanclarke4646]

25:27 for me.

[@zirco77]

At 21:48 "...hopeful I can do the rest by sudoku", then merely 2 seconds later, interrupting himself mid-sentence: "see... this is a naked single" out of nowhere 😮. Classic Mark! I mean, had I searched for a naked single at that point, I'd barely have time to scan a line in those 2 seconds, wheres Mark sort of sees everything at once. Or maybe he scans horizontally with one eye and vertically with the other? 😅Anyway, that's surely one of the reasons he's a Sudoku Champion.

[@GregDorn]

Another miracle, another one with disjoint subset and horizontal and vertical banding. It's almost like you could start using those as un-written rules. I wonder if it could be proven

[@RichSmith77]

This one doesn't have horizontal roping though.

[@David_K_Booth]

If this were a piece of music, it would be called a bagatelle. Aad's compositions are always a pleasure. (Edit for spuddled melling)

[@peethoagland8907]

Aad!! I made the exact same error as Mark in my solve on R3-C8.

[@steveunderwood3683]

Very easy start, bit of fiddling about, then everything just fills in.

[@lazyhaus]

:( 01:42:37 for me

[@matthewphillips5911]

Aad, you magnificent rascal. Went from seeming unsolvable to finished in 20ish minutes. Not sure how I avoided the mistake and still ended up taking longer than Mark, but I guess that's why he's a world champ.

[@ruizlightning6683]

Simon did this, same solution. kzbin.info/www/bejne/rYbRn4utgbmVpKMsi=MPNik84tYUwMw0Ah

[@hrenes]

2 geniusses at work: Aad and Mark! great sudoku, great solve!

[@dereklevy]

Just a pure brute force puzzle with a bit of logic thrown in. Loved it!

[@Ardalambdion]

Simon solved this a few years ago, calling the puzzle errr what?

[@geoff544]

Same puzzle but with slightly different rule set - title was 'The Sudoku With Only 2 Given Digits' - 3 May 22

[@RichSmith77]

"Errr what...?" appears in the thumbnail for that puzzle, but wasn't the puzzle title. The solution grid is identical. The rules were almost identical, but gave the added restriction that the digits on all the positive diagonals had to be unique. (That property was just an emergent property in this edition), and also the original requirement was that all the differences had to be at least 4. (It was an emergent property that all the differences ended up being 4 or 5 in the original). Not surprised it's called Deja Vu - so similar. It feels odd that there's three years between the two.

[@JohnBodoni]

mark, my favorite variant of that saying is heard from the pasture: to err is human and to forgive, bovine. :)

[@RecreationallyCynical]

I disagree with the notion of calling that the positive diagonal. Simon says if you plotted it as a graph it would have a positive gradient; but unlike a grid, the origin is in the top-left, not the bottom-left. There is a negative correlation between row and column number (as you increase the column number on the diagonal, you decrease the row number). I prefer to just call it the up-right diagonal (and the other diagonal the down-right diagonal). In matrix mathematics, the rows and columns also originate in the top left like a Sudoku grid. There they use the terms "main diagonal" or "principal diagonal" for the down-right diagonal, and "anti-diagonal" for the up-right diagonal. If you dislike using mathematical terms, then I agree with you, and we should ditch the term "orthogonally connected" and just use "contiguous" instead.