A Dutch Masterpiece

[@ninjafruit816]

Finished this one in 13 minutes. Although I had to play the video at 2x speed...

[@tangyspy]

+

[@Andrewkosche]

Lol so many people saying ridiculous times this comment is great

[@blabla-rg7ky]

how the fuck did you fin.... oh!

[@amadeuz8161]

Odd that you had to 2x the video cause he did the puzzle in less than 20mins so 13 doesnt equal 10 and at some point he was ahead of you then so you cheated :D

[@tezcharold]

This should be called a windmill sudoku, very dutch name, and the solve felt like it went round and round, and it even looks like a windmill (kinda).

[@livedandletdie]

That's the first thing I thought about it when I saw it. Wind-Mill Puzzle.

[@TheRodBelaFarin]

Is it possible to make a video about how to create a puzzle like this. I can't even slightly imagine how to do something like this. Great video as always

[@luukipuuk3537]

I have never known how to do any kind of sudoku, I have no clue why youtube recommended me this, but it’s really pleasing and nice to see you get so excited over solving this!

[@Tahgtahv]

As an additional bit of beauty. Every set of repeated digits in a standard 3x3 is in a knight's move pattern. There are 2 sets of every digit repeated except for 6, which appears in each 3x3 box exactly once. As mentioned in another comment, the 9, 5, 2, 3 have rotational symmetry, as do the 4, 1, 7, and 8. 6 has rotational symmetry with itself.

[@zylinbia2575]

ahh I noticed that too! I was hoping he'd figure it out since he mentioned geometry at the beginning but he never did

[@Keyboardje]

I do so enjoy the noises Simon makes whenever he sees something new! :D One heck of a puzzle!

[@12tone]

This may be the most brutal puzzle I've ever successfully solved. Took ages but I loved it. All the logic seemed really fair, even if it was incredibly hard to spot at times.

[@modulusshift]

12tone yeah, I gotta second this. I feel like if I was a little sharper I would have been able to see why the internal windmill squares had to be symmetrical, but it was at least possible to solve around it, and Simon had to do the same so I don’t feel too bad. Brutal, but fair. Much appreciated, Aad. :) The symmetry I’m referring to: in the twelve squares that match the gray ones, more specifically the 8 that surround the central square, the duplicates are knight’s moves around the center, two squares forward and one to the side, and the shared grey square they refer to is in the corner between them.

[@KDOTott]

oh hey, just wanted to say I love your music theory videos. pretty cool that you play sudoku too.

[@modulusshift]

The Roadcone you're probably thinking of someone else? Or you're a time traveler and I should look into doing that. :)

[@KDOTott]

@@modulusshift I was replying to 12tone, he's a great resource for musical analysis.

[@modulusshift]

The Roadcone oh, cool. Looks good, I'll check it out.

[@traviskelsey6674]

I was only able to solve this because of his initial geometry hint.

[@bloodfirstykillr6424]

Wow because just from watching I just saw symetry

[@RabidParana1]

Yup I was clueless for 10 min came to the video for a hint saw him highlight those 3 rows and went to town. Still took 2 hours though

[@amadeuz8161]

I saw it but couldn't prove it and only like 33% sure they would be the same numbers so after like 10mins plus a smoke I had to watch until he said it, after that it was really fun :D

[@draconicdusk5911]

Tip: fill in the given numbers (Yes I could do this for some reason) The checker for some reason is seeing those given numbers as empty cells. Once I filled them in manually the check system told me it looked good! Edit: Also, brilliant puzzle, absolutely mindblowing. There was some beautiful logic here that I hope Simon picked up one!

[@Tehom1]

I have no idea why that works, but it does!

[@SgtRok214]

I had the same issue and was wondering why it was marking the givens as incorrect. Great puzzle, although I prefer other software

[@KCML82]

that worked for me. Guess the checker doesn't check the boxes, but the rows and colums for repeated numbers.

[@michaelholdowsky6386]

Thanks. I spent the last 6 months trying to overcome the checker saying that the given numbers doesn't look right. Given my expected life expectancy, that is 6% of my remaining life span that I could have spent doing the important things in life. Like chess sudoku with thermometers.....

[@thabutters]

Brutal one. Took me almost 2 hours, and a piece of my sanity. :) The brain is wired to think in standard 3x3 blocks and I constantly second guessed myself, double checking everything. I hope to see more puzzles like this, so I can get my brain around the logic to do them faster. :D

[@MsCatwoman111]

Whoopee!! I did it! But must admit if I hadn't listened to Simon's comment about the rows of three equalling three of the shaded cells, I probably couldn't have done it. But I'm still delighted!

[@Pyrois]

This one was absolutely mind-bending. Great job on the solve! This is definitely one of those puzzles for which I was perfectly content with just watching the video :)

[@gordonglenn2089]

I have to admit: I was a bit disappointed that the center number did not turn out to be 8, the only digit missing from the given number set.

[@DiMono]

Around the 18:00 mark you can limit R3C1 to a 38 pair. Whichever of those goes into R4C4, the restrictions in box 1 make it so. Not highly important, but sped up the end of my solve slightly. Of course, I spent 15 minutes not noticing that R9C1 was the only place a 7 could go in that region, so I'm not exactly a top solver. I just happened to notice that one. My solve time was about an hour after restarting due to a logic error. I really need to train myself to stop relying on pencil marks so much for these, the cleaner grid makes it so much easier to notice things in Simon's solves.

[@snigbylife]

I’ll add my WOW to this as well beautiful.

[@LithmusEarth]

11:48 and the 5 is in the upper of the two highlighted squares, because the 3rd grey digit on the right side of the screen, cannot be adjacent to itself, for sudoku reasons. Beautiful Construction so far. 16:48 and the 5 is in Row 9 of Column 4, because you need 156 in column 4, and you can't put 5 in either of row 1 or 2, because there is a 5 in the box, so it's a 16 pair, thus 5 is at the bottom. 20:36 that breakthrough gives you a 3 in column 1, row 3, but i assume after that move just now, it's all over. 22:51 yep 1 in R9C9, it's just cracking. You broke through the logic, man that to me is always the hardest part, the approach.

[@timsullivan4566]

Once you explained that with the irregular shapes, the 3 grays in a 3x9 had same digits as the 3 extruded blocks, then things went from "Grrrr!" to "Challenging but fun and do-able."

[@rahulbishnoi8273]

Absolutely Amazing!! Started playing Sudoku again yesterday after years to pass time and ohh boy I am hooked now

[@Adrian_Grey]

1:09:52 Needed the geometry trick to get started, but once I got that, I could sort out the rest. I've played a few of Aad's puzzles that you've featured and they're absolutely my favorites. Always very clever, yet not too difficult for an amateur to solve.

[@tremkl]

I watch most of the videos on this channel, and I have to say that without a doubt this was the most wonderful puzzle I've seen. It was a wonderfully unique Sudoku with a wonderfully unique solution.

[@juanperret7044]

Took me an hour. Got mad when the checker told me it was wrong

[@vittorio1159]

Me too

[@InaSchmidt84]

Took me 1.5h. And now it tells me it is wrong....??? Must be an mistake, glad i am not the only one. Thats frustrating....

[@robertr7923]

@@InaSchmidt84 listen to 24:15, the checker looks at 9x9 boxes and rows and columns :) there is a good chance you all got it correct. You should just check for yourself if any digigs are repeated in teh boxes or diagonals lol

[@dcay5424]

@@robertr7923 Actually, you only need to fill out the starting numbers, for some reason, they are only "pictures", not numbers. I just put on 9 over the predestined 9 and so on i actually got that it looks good.

[@Jack-kx5rf]

The checker only checks against normal sudoku rules. If you have completed it correctly you WILL be told it's wrong using the checker. (For example, there are 2 2's in box 9)

[@simmo5071]

Your start has me mind boggled, cannot begin to see the logic used.

[@malloryrobinson6418]

I love these kid of puzzles! Jigsaw sudokus with extra varients are soo fun!

[@zacharymorritt3228]

Spent 5 minutes on this without getting a single number.

[@zacharymorritt3228]

Then watched the first part of the video and it finally clicked! 30 minute solve, great fun.

[@erikliubakka6514]

Took me 4 hours to solve. 3 of them were slowly picking away. I was using the "geometry" trick, but not in the intuitive way he described it. After I watched the first two minutes of this video I went back and finished up the puzzle in like 10min

[@TheBernuli]

I spent 40 minutes for first number :D now I am on 2 hours and I realized that I've wrong.

[@lakarto19]

Wow. One of the most brutal puzzles I've ever seen on this channel... I won't lie, this puzzle took me over two hours to solve and only pure stubbornness stopped me from watching the video before attempting to solve it on my own. Just wish I had spotted the initial geometry trick, it would have made for a much more elegant/efficient solve. Guess I should stick to classic Sudokus for a while now.

[@rahkshirock96]

I noticed about halfway through the solve that the puzzle was radially symmetrical, and solved it that way, glad to see you don't have to make that leap to solve it!

[@petemagnuson7357]

Oh, that pretty! The cycles seem to be 1-4-8-7, 5-9-3-2, and 6-6-6-6.

[@robertjandegraaf5557]

Very clever puzzle indeed. The trick is to see the numbers in the three grey areas in the three 3x3 boxes as a COMBINATION OF NUMBERS, not as a mapping of each grey box belonging to one of the three boxes outside the three 3x3 boxes.

[@batdowg]

Solving this puzzle gave me chills. WOW!

[@dsynn1992]

The beauty of this puzzle is that the symmetry of the "irregular" shapes actually give the entire puzzle perfect rotational symmetry. The pairs 15/38 and the pairs 27/49 always show up as their counterpart in their 180 degree equivalent. Easier to see if you color code the 4 pairs

[@edkroketje1]

After an initial hint of watching till 10:35 (although I somehow did spot the first 5 he placed before he placed it) I paused the video and made the rest myself. Took me 2 freaking hours but I managed to complete it so I am extremely happy that I could still do it actually.

[@CoffeeHead27]

I wonder if Aad Van De Wetering sees Cracking the Crryptic, and if he knows just how much respect and appreciation a lot of fans have for him as well.

[@mikepictor]

Your comment about the check button, you are right it complains, but it does NOT complain about the 2 9s in "box 1", but it does complain about the 6 in R6C1 ... which is alone in its "box" ... Whatever logic it's using, it's not generic sodoku

[@goster4070]

Great video! Gelukkige verjaardag, Aad!

[@ericjones3692]

If you realize each section is identical in relative positions, it is very simple. What keyed me into it was the geometry. The 3 greys in each side match the 3 outliers. Well... They have to be relative to each other. So, once you find where one of the numbers go, you can mirror that to the other sections. The corner greys had to be in 2 different outliers, which means they would have to appear in the same relative positions in order to maintain the symmetry. That means when you find all the greys, which happens pretty quickly, you only need actually solve for 18 cells, of which 6 are given to you.

[@ericjones3692]

Took me about 15 minutes solving it this way

[@lylecampbell8288]

I noticed the 4-fold rotational symmetry & couldn't resist using it. Things fall quickly into place if you do. Its not actually a bad assumption to make as the regions also have the same 4-fold rotational symmetry.

[@lunafaekaida1772]

1:19:10 what a doozy of a puzzle. some brilliant logic though. i made heavy use of highlighting to find hidden singles and box logic, really getting a bit frustrated with some of the limits of it. accidentally highlighting a square and having to re-highlight everything again can be really frustrating

[@gposchman]

Well if you got it wrong, I did too. It was a marvelous puzzle. I had a couple of logic fails, but they showed up quickly and I could go back and correct it. I'm slow and steady and the grey squares kept messing with my head. I felt it was a bit of an outward spiral and a back inward to finish the solve. Great video, thanks for the geography clue at the beginning, without that I may still be pulling out hair.

[@brianrichter8255]

This seemed like a perfect candidate for switching around the givens, a technique from an earlier video. You can create bogus givens and put the numbers 1 through 9 anywhere you want (and maybe color the existing givens to clarify you’re ignoring them) and solve the puzzle. In your solved bogus solution you’ll probably have some of your digits that don’t match the givens. So to fix it, you swap the digits in your bogus solution until they match the actual givens. For example, you might solve it and find that where a 5 was originally given, you had placed a 4 instead, so then (after coloring your bogus 5s to avoid confusion) you have to change all your 4s to 5s. Then you have to change your (colored) 5s to whatever given digit one of those bogus 5s landed on, and so on for the other digits until you match all the actual givens and have the actual solution. I tried to do this by putting bogus givens all 1-9 in a single shape, in all the grey squares, along a row or column, and along a diagonal, but none of these seemed to make the puzzle any easier. In the end I had to watch the video to get the main geometry logic and a couple of other deductions that I was not seeing. BTW, you can type over the givens with your own “final” digits. When you’ve solved it correctly and typed over the givens with identical solution digits, the checker does seem to like it! If you don’t overtype the givens, it flags them all as errors.

[@marvinmarvin38]

I actually used check and it worked. (except I had to refill the prefilled blocks) what an amazing puzzle.

[@ukdavepianoman]

It really is a stunning construction. How anyone conceives such a thing is beyond comprehension. Seemed to be a slow and difficult start but then accelerated as it got easier.

[@JaggerG]

I started out this one kind of brute forcing grey cells. I still ended up seeing elegant logic later on. Great puzzle!

[@cameodamaneo]

22:19 C5R3 should be an 8, which resolves the 48 pair at C6R2 immediately...

[@Qazqi]

Almost 2 hours including two occasions of finding a mistake and having to practically start over. My head hurts. Edit: No wonder my head hurt. I spent almost 10 hours trying to sleep off a horrible headache after that puzzle rip

[@BobMcBobJr]

This one was actually really easy once you see the rotational symmetry. Then it's just copying numbers around in a circle.

[@batdowg]

That poor 4 in row 3 was feeling VERY neglected, all the way from minute 19. "48 pair over here, feeling like I should be able to resolve that..." and the 4 is screaming his head off (22:15)

[@britefeather]

this one also has the symmetry. 1 is related inversely to 8. 9 to 2 3 to 5 4 to 7 6 to itself

[@lordscottish69]

The birthday music was a nice touch!

[@gailivey2015]

For some reason, I cannot wrap my brain around the logic of this one at all!

[@GamerBugsTwitch]

That one really was beautiful! I cant yet do something like that cos i dont have your logic, but seeing you do it was very satisfying. Its only natural for you to not see some things right away cos you are doing sudoku and thinking obviously of boxes. Would enjoy more that have different shapes like this.

[@kleozyn4179]

1:12:14 for me! such a nice Sudoku!!! loved it

[@ChristopherBreeden85]

This is an incredibly remarkable puzzle.

[@mikepictor]

man...your discovery at 9:50 ... I had the grid completely filled with 2, 5, 6, and 7 and half the 1s, before I had to come get that hint.

[@lucasb6517]

i'm slightly confused by his idea with the replenishment in the beginning. I understand that the sum of the three grey squares must equal the sum of three white squares off to the right but I don't understand why they must have the same exact values. Further more, if you try to apply that logic to the five and the missing square to any of the top two grey squares, you get a situation that is impossible

[@RandomBurfness]

What an INCREDIBLE puzzle. It took me well over an hour to go through this monster. But wow, everything here fell into place JUST when it needed to. I am in awe of this construction. EDIT: I was able to make the software say the solution was correct by strangely enough just writing in the given values in the cells with given digits. It said it was okay.

[@harrisons62]

43:20 for some reason the software says all the black numbers are wrong...

[@twirdman2]

That puzzle was just beautiful to watch but I don't think I would have been able to solve it given a million years.

[@MinimumGnome]

Another great puzzle. Took me a little over an hour. Started watching your channel about a month ago. Prior to that would not even have attempted a puzzle this difficult. It's great to see the progress in myself just from your channel.

[@damienreave]

The very first number I entered was a 4 into the upper left gray cell, mistakenly thinking it was forced to be a 4. I did okay-ish with the rest of the puzzle for a bit but it was doomed from the start with that mistake. Great solve!

[@MarcusAntonio.]

freaking out thinking i messed up. then watched the video where hes says the checker is wrong. So if you do the puzzle and think you have it right... you may have it right. the checker isn't working for this puzzle.

[@helenwoodward9233]

I did this one in about 2 hours with a bifurcation at the end, having missed the geometry trick with the center. Then I watched the video because I knew I had to have missed something, and with that trick I could have done it in probably under half the time. On the one hand I feel dumb for not having spotted the trick, but on the other I'm pretty proud of myself for solving the puzzle without explicitly realizing the trick (I did definitely realize that the number of boxes available for the 3 edge rows/cols were important)

[@zackdwyer7489]

I can’t solve any of these puzzles on my own but I enjoy following along with your logic (: glad I found this channel

[@justsomeguy892]

So regular sudoku rules don't apply in the 3x3 grids? (For example: at 12:21 there's two 2's in the bottom right square.) If so, doesn't that make your geometry hint at the beginning just a guess? (because you said that each number appears exactly 3 times in the three columns.)

[@dsch772]

I would've actually been much easier if you utilized the rotational symmetry from the very beginning. You can get the 4-1-7 and 9-5-2 triplets pretty quickly, then it's just putting 3 and 8 into them to form two quadruplets. Now you can tell that the left-out number is 6, and the middle one has to be 6. I broke the 3-8 pair by restricting the 3s on the top rows, then everything resolves.

[@Leonideez]

Symmetry about the center 1-8, 2-9, 3-5, 4-7, 6-6

[@indy1061]

Don’t know if someone has mentioned it before, but the first e in Wetering is actually pronounced like the a in amen! :)

[@Felixkeeg]

I got some 2's in and some in the central 3x3 after 1,5 h, but I never noticed the logic behind the offset numbers and the grey cells. Welp, there goes "Oh, only 25 minutes for him, I should be able to do that"

[@andreash2254]

04:30 ongoing. I would really like to understand it, but i can not :(. Why do these numbers must be the ones in the grey blocks? I really do not get it. Can someone please explain it in detail? Thank you :-)

[@mrbigstuffication]

The three full rows three rows have to have 1-9, because they're rows. But each of the three contiguous segment also has to have 1-9, right? In a normal Sudoku, this works easily, but this puzzle has 3 shaded segments in that whole area, and the segments extend past that area. Any number in the shaded segments is contributing to the row/column, but *isn't* part of the segment. If the shaded areas are 1, 2, and 3, and the rows are correct, then to complete the segments, we need to put a 1, 2, and 3 in the three spots that aren't a part of that whole three-row-wide area.

[@BlueCyann]

If you don't follow Simon's explanation I doubt mine will be any better, but I'll try. Color the irregular shapes at the top of the puzzle (the top three). Make them blue or something. Don't color the gray cells, just the three shapes. Take a good look at the blue shapes. Each of these shapes has to contain the digits 1 to 9, once each. This makes 27 digits in total: 3 each of 1 to 9. Most of these 27 digits are in rows 1 to 3 of the grid, but three are down in row 4. Imagine these three cells down in row 4 have been determined to be a 5, a 3 and a 2. How many 5s, 3s and 2s are left in the rest of the blue area? Two each, right? Now highlight the top three rows of the grid. How many 5s, 3s and 2s are needed in these top three rows? Three each, as each row needs to contain one of each number. Top three rows need three 5s, 3s and 2s. Within the blue cells, top three rows only have two 5s, 3s and 2s. So the three gray cells have to be the missing numbers: one each of 5, 3 and 2 in some order.

[@s9ecera]

I am really a bit puzzled why you didn't apply the pattern with the knights move with for 5923, including the corner greys, as well as 4713 laying on the corners neatly together with their corresponding greys of "the inner circle of greys". However, you found the way. A bit more cumbersome that way, but ...

[@raised_OOT]

Cryptic- “This puzzle is extremely difficult” Me- “This looks cursed as fuck

[@melihutkukocer7400]

Just found my fav. channel.

[@jstlroot]

Wow, brilliant! Thank you so much for sharing

[@stevesebzda570]

Interesting fact.. That 3 you were wondering about in that bottom left shape (having that 3 in the grey shape from that 3 you were proposing in row 4), They both ended up becoming threes down there in that shape. Now if only someone could explain to me how he deduced that grey shape down the bottom being a three from the proposed 3, then I'd be set lol . [[ Edit: @6:33 onward a bit ]] This puzzle just kept messin with my head 😮😂☕

[@Dankman9]

Wow, can't believe I managed to solve that one, took me over an hour and I got super stuck at one point and almost gave up.

[@vlahovivan]

I solved it in an hour and 23 minutes, and I must say this was a great puzzle.

[@liiiinder]

5h40min ... must be some kind of record... After 2 hours I started looking at this video, and stopped at 7min , 2 hours later when everything failed I watched 10 more seconds and just got furious :D "AAAHHH I THOUGHT I SPOTTED SOMETHING CLEVER THERE ..."

[@RoderickEtheria]

Interesting what pieces it considers incorrect when you submit the grid to check.

[@korbsen]

Maybe in cases like this you can tell people not to hit "check" on your website after solving right at the start of the video? :-P I searched forever for my mistake before finishing the video and finding the answer ;-) Great video again of course!

[@kevinlund357]

Took me over an hour, but that was a hell of a puzzle.

[@OskarCzechowicz-OmniMusician]

Of course it’s a genius puzzle. But nobody noticed IT IS FREAKING SYMMETRICAL! 6s are following the windmill, 1s are opposing 8s and so on.

[@thomashjelm2928]

At 9:55 he says if an 8 is put in 4th row, 6th column that 4th row, 4th column would also have to be an 8, but I am missing how he came to that conclusion. Why couldn't it be a 3 as he marked? Can anyone help me understand?

[@s9ecera]

If the 8 is in c6r4 it has also to be in the grey box c1r2. (all three grey boxes in row 123 are repeated in row 4 c567, and the 1 and 5 are taken. But if 8 is in grey box c1r2 it has to go in c4r4, because the grey boxes in column 123 have to repeat in column 4 r345, and the 4 and the 9 are taken.

[@pbmander3949]

This puzzle is extraordinary

[@willysunny]

Mark, just want to verify, your instinct logic at 7:03 actually checks out as that square is the only placable 3 in that entire line, no?

[@soundcrank6214]

Ahh bobbins! Love it

[@christophseeliger5551]

I have to admit, I wasn't very impressed by the Pi-puzzle, but this is a whole other level. Great puzzle and great solve! And of course Happy Birthday!

[@redsox2722]

I really want a response from @cracking the cryptic here - is youre downloadable software the same as your online one? I love your online one. But I dont want to spend the money if it's not

[@billiardsprofessor]

Looks like you hard-coded the givens. So the solver sees them as blank.

[@ookazi1000]

Warnings about whether the solver will be able to check a puzzle would be nice at the beginnings of videos: I spent ages going mad looking for the error that wasn't there.

[@Kurgosh1]

This was great. I think I got it, after only 2 hours-ish. Now to watch and see if I got the right answer.

[@s9ecera]

@cryticcracking Somewhat fasicinating that you never picked up the complete symmetry in this puzzle. For every number you placed you could have look at its counterpart in the grey cells and by that find three other numbers too place. Just see the pairing of the 4s 1s 7s ans 8s in the grey boxes and their diagonal neighbours. This repeats for every number throughout the puzzle. It is a complete windmill.

[@murphy9453]

Enjoy the site but it seems to be increasingly difficult to find just plain old Sudoku puzzles (without special rules, etc) on your site.

[@phos4us]

I figured out the 1, then decided to just watch instead

[@robertmeadows1657]

My brain doesn’t like irregular boxes.

[@peterdavis9403]

Made a mistake somewhere in middle, split into 3 copies and each variant failed so I started from scratch and got it right. Unfortunately the process took me 3 weeks..But I enjoyed doing it.

[@Saryk360]

I was always taught that if the last digit you put in matches all the rules (row, column and box in a standard sudoku), the puzzle is correctly completed. Is this right ?

[@MakiOfSpring]

Nope, imagine for example the extreme case: 999|919|999 999|929|999 999|939|999 -------------------- 999|247|999 246|1 3|789 999|869|999 -------------------- 999|979|999 999|989|999 999|999|999 If you put in a five in the center, it matches all the rules for its column, row and box, but the Sudoku is clearly completely wrong

[@marcosdiez7263]

I'm sorry, but I don't see how you concluded at around 4:30 that the leftmost 3 grayed digits must contain the 4 and the 9 from knowing the sum of the first 3 columns adds up to 135. As I understand it, the candidates sandwiched between the 4 and the 9 in the 4th column can be 1, 3 and 8 at first glance, for and addition of either 14, 16 or 21, which ONLY means that the sum of the 3 grayed boxes could be 14, 16 or 21, and even if we pick the 1 (the value you ruled out) to be sandwiched assume this sum to be 14, and then... What forbids those 3 grayed cells to assume any value adding up to 14, for example 3, 4 and 7, or 5, 2 and 7? Because of this ambiguity, I don't see possible to rule out the 1 the way you did. all we know is the topmost grayed squares are the sum of three values 1+x+y whose result must be equal than 5+r+s from the fourth row. Your solution meets the puzzle constrains, but just because you assumed an additional constraint that weren't in the rules, even when it seems the author expected us all to think the same way to reach to a solution. Unless there exist some math property from the grid allowing to claim no different candidates adding to 14,16 or 21 than the 4, 9 and one of 1, 3 or 8 that made up such aditional constraint, which wasn't clear from your explanation.

[@jaundice27]

Is that a Bradford crest?

[@BrentDeJong]

jigsaw sudoku! but a more fun variant of it :) took me about an hour - without watching the video!

[@SweetAndSourCat]

I managed to solve this one, and I was so proud until the webpage said it didn't look right, so I watched your video and then checked all my numbers and I have the exact same solve as you. Maybe there's a glitch with the system? It's highlighted all the original black numbers in red, and I didn't put them in so they can't be wrong... Lol

[@grai-like-gray]

Ah! The checker had me thinking I did something wrong lol.

[@sunriselg]

The irregular geometry really messes with my head. I always want to eliminate digits based on the 3x3 block. I never would have seen the initial trick without watching the video. It's also funny whenever you say "that's me being slow" - that's fine. You're still 3-10 times faster than me on most puzzles.