This Puzzle Was Made By A 12-Year Old!!

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** Today's Sudoku **
Prepare to be humbled (unless you're very young!) Today's puzzle has been set by grkles and his son GabeyK9, who is only 12 years old. It's REALLY good and returns to the 159 theme some of you will have seen before. Give it a try at the link below:
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Rules:
Normal sudoku rules apply. Digits in a circle must appear at least once in the four cells touched by the circle. A digit in column 1 indicates the column in which the digit 1 appears in that row. Columns 5 and 9 have the same rule for the digits 5 and 9 respectively. (For example, an 8 in R7C1 tells you there's a 1 in R7C8. A 3 in R2C5 tells you there's a 5 in R2C3.)
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[@grkles7640]

WOO! My kid is so excited, I'm gonna watch it with him tonight :) :)

[@alexholker1309]

He did a good job. I think 1-5-9 might be my favourite Sudoku variant, and this was no exception.

[@jplefaivre]

This was my first time playing a 1-5-9 variant and it was heaps of fun.

[@_raumplaner6575]

They somewhow put Aad in the title. I hope that can be changed. Congrats anyway to both of you.

[@longwaytotipperary]

Wow - that was fantastic setting! Cheers to both of you!!

[@matthewjohnson6360]

You'll need to Message Simmon so he can say when he makes the next video about how your kid like it.

[@grkles7640]

Editing my previous comment isn't working, so here's a new one. We watched it, what a great solve! You found basically every little cool thing we managed to build in. Thanks so much and I'm glad you enjoyed it! Re: the title, it's simply a Quadruple 159 puzzle, so we decided the title should reflect that ;)

[@ellaenchanted2399]

Your 12-year-old is amazingly talented. This beautiful puzzle definitely deserved to be shown :) On a separate note, I honestly thought the fourth 9 was in reference to the puzzle-name GabeyK9 ;).

[@chitraagarwal8259]

I can just imagine how much fun this must have been to set! It was an absolute pleasure to solve and Simon's excitement was delightful as always! I wonder if someone was able to solve this without using the 1-5-9 secret.. i do think the quads had enough clues to do it without consciously following the secret

[@_aullik]

I mean there is a bunch of work in the background, but recording 2 videos per day in an 8 hour working day should be possible for each person. This means 10 videos in a 5 day week which gives 3 videos as buffer in case something happens.

[@tobyonatabe2601]

@@chitraagarwal8259 ummmmmmm, what’s the secret?

[@tobyonatabe2601]

@@chitraagarwal8259 update: I’m facepalming aggressively at the moment, as a person who did painfully solve the entire puzzle oblivious to the secret. Took me over 3 hours lmao.

[@dominatorbuzz8659]

i just recently found this channel and man the community is so wholesome, love it 🙌 over 100 likes 😅😅 dont think ive seen that yet. thank you guys for welcoming me ❤️

[@tangrybird04]

We’re glad to hear that : )

[@shalaz1981]

Welcome!

[@kathyjohnson2043]

Welcome!

[@paulconway670]

I strongly recommend going back and watching all the vids in roughly chronological order... as Simon and Mark develop the channel over time, so do the techniques - you'd lose the discovery of things we all take for granted now :)

[@dominatorbuzz8659]

@@paulconway670 i was definitely planning on doing this! appreciate the tip🙏❤️

[@randysavage1011]

Have Simon or Mark missed a single day in the last three years? The changes in my life - the Pandemic, career moves, relationships, cities…and here is Simon being my constant.

[@chris5619]

I don't think they have. In one of Mark's videos this week though, he said that he just got back from holiday and the videos from the prior days were either pre-recorded or he also recorded some on holiday. I've always assumed they must keep at least a couple ready to publish, in case of emergency, other plans, or even if they spend over an hour recording for that day only to get stuck on the puzzle and not publish.

[@LednacekZ]

i think there have been some days where there was only one video, but it was probably only a technical error.

[@Dragonlord446]

LednacekZ probably time zone

[@jessevennard2640]

Constantly finding the hardest possible solve path

[@glennmelven3414]

I am so thankful they have not missed a single day of putting out 2 videos per day since the pandemic started. I don't think they planned for it to continue, as for the 1st 100 or so days they actually counted them. But, when they saw how much it helped people they decided to continue it.

[@HotCrossGuns9]

Think you've still got part of yesterday's intro as it says it's by Aad, which confused me as I didn't think Aad was 12!

[@sonalita_]

25:51 "you can come to an absolute grinding halt" hovering over the 36 pair in the box. Never change Simon, never change.

[@DArtagnonW]

No digit after 10 minutes of staring. Once you mentioned the trick, I went "What!? Oh, of course!" Gonna go find another 159 to do, now that I'm properly armed.

[@inspiringsand123]

Rules: 04:33 Let's Get Cracking: 06:13 Simon's time: 27m31s Puzzle Solved: 33:44 What about this video's Top Tier Simarkisms?! The Secret: 7x (06:20, 06:43, 09:12, 10:26, 12:17, 31:19, 34:11) Maverick: 1x (22:41) Schrödinger Cell: 1x (17:46) And how about this video's Simarkisms?! Ah: 15x (08:37, 09:41, 10:16, 12:58, 16:59, 20:25, 21:37, 24:04, 26:35, 28:55, 29:01, 29:21, 30:18, 32:46, 32:55) Beautiful: 7x (09:41, 10:16, 17:35, 24:42, 26:35, 26:35, 26:40) By Sudoku: 7x (11:06, 21:55, 24:36, 29:06, 31:02, 32:39, 33:29) In Fact: 4x (00:34, 17:26, 27:38, 30:53) What Does This Mean?: 4x (16:43, 19:32, 20:13, 26:21) Clever: 3x (11:03, 12:52, 16:34) Pencil Mark/mark: 3x (08:02, 09:41, 09:54) Stuck: 2x (13:11, 13:36) Lovely: 2x (18:48, 20:25) Deadly Pattern: 2x (19:19, 32:11) Hang On: 2x (22:48, 29:04) Magnificent: 2x (33:46, 34:21) Obviously: 2x (07:41, 18:30) Cake!: 2x (02:08, 02:12) Good Grief: 1x (32:24) The Answer is: 1x (19:54) Brilliant: 1x (26:55) Going Mad: 1x (17:51) Shouting: 1x (01:54) Marries Up: 1x (23:21) Which Means What?: 1x (20:09) Next Trick: 1x (11:41) Fabulous: 1x (03:59) Most popular number(>9) and digit this video: Twelve (3 mentions) One (84 mentions) Antithesis Battles: Low (10) - High (5) Column (27) - Row (13) 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!

[@copshotakid5764]

no way

[@berendharmsen]

Interesting

[@tobyonatabe2601]

Never thought I’d see the day that bots would provide information that all recipients would find interesting in a way.

[@HunterJE]

17:34 You also can't put a 56 pair in green because if you try to fill it with both 5 and 6 you'll have a second 6 in the same box to index the 5...

[@TheSonicPerson]

0:11 "111155559999 by Aad van de Wetering"?

[@BarryKort]

Yes. The Title Slide is 'wrogn'.

[@Laura-vs6fs]

I love the fact he is carrying his love for puzzles over to his son! I started solving sudokus when I was 10 years old and they really are my comfort hobby to do. So glad I found this channel as the hosts and the community are so lovely and let's not even talk about you guys' consistency as it's insane

[@jessevennard2640]

I have my 6 and 4 yr olds doing 4x4s. Future subscribers

[@Mischa-dc4og]

@@jessevennard2640 gotta teach them young :))

[@matthewcharlap7785]

just over an hour here. SHOULD have been about 30 minutes though. "Why?" you ask? Because at about 25 minutes or so, I was stuck for almost half an hour (literally staring at the puzzle without so much as a pencil mark added), when I suddenly realized the 1-5-9 constraint works both ways (i.e. if a cell CANNOT be a 1/5/9, then c1/c5/c9 in that row cannot be that column-digit!). Once I thought of that, it took about 5 minutes to finish. I feel both good and bad - bad because I didn't see that bit, but good because I persevered through the block and did manage to finish with looking at the video.

[@meganhorton7739]

Thank you for the birthday wishes and a happy 5th birthday to cracking the cryptic!!!

[@Fogmeister]

There’s so many times where Simon replace one set of pencil marks for centre pencil marks and undoes work that he previously did. Corner marks of 12 and 123 and 134 will get replaced with centre marks of 1234 in all three cells for example.

[@mohamadkaddoura3353]

4th 9 for the 9 in GabeyK9?

[@christianloder8127]

That was my thought too

[@rontyson6118]

Grkles said it was just a quadruple 159 puzzles, so the name should reflect that.

[@joelstevens5670]

I seem to be running out of superlatives these days but the quadruples indexing quadruples idea is terrific! :) Thank you to both setters, that was enormous fun to solve. A big thanks as well to Simon and Mark for all that they continue to do to showcase such brilliant sudokus.

[@TheShadowplayer]

I think you are totally right about your theory of being this kind of puzzle a great match for a software programmer/developers brain. I‘m one of these creatures and I never saw so many missed clues after the break-in in any video before 😂👍🏻

[@leojs5673]

0:09 whoa Aad is younger than I expected 🤣

[@Zeratul877]

The intro screen says this is by Aad van de Wetering was that not yesterdays puzzle setter?

[@borticus101]

I was totally stumped until you told us "The Secret." Then I finished it myself.

[@majora4]

I got 42:11 but I never would have solved it without the video. Once I learned "the secret" of 1-5-9 puzzles, most everything fell into place. A few other bits stymied me, as far as figuring out where the digits have to go on the 2-4-7 and 2-3-4 rings. Very impressive puzzle, and looking forward to seeing more from GabeyK9.

[@KAPsub2]

It wasn't much harder without knowing the secret. The logic falls into place pretty naturally without having to know it's a repeatable trick. I had to come back to the video for help at the end because I was for some reason just blind to the 247 clue placing the 7 in box 4, but I had all but solved the 1, 5, and 9 columns by then

[@RealCadde]

20:35 If you'd slowed down a little and considered the implication of R6C2 and R6C3 not being capable of being a nine... Where does the nine go in row 6? In column nine of course as that's the only place it can go.

[@markp7262]

22:41 finish. My daughter is not quite ready for setting puzzles yet (I still haven't set one myself), but I'm hoping that she'll get there. Excellent job to the grkles family!

[@Chockrit]

I did not know the secret about the low/medium/high digits for my entire solve. The way I broke in was realizing that the 5 in box 5 must belong in either the 2356 or the 5678 quads, when you carry that through it breaks the 5's in box 6. Then you have to eliminate the possibility that the 5 is in box 5 on the 5678 quad, which is again broken by the indexing of 5's into box 6 again! Once you do this, you can pencilmark 5's in the whole grid and you're off.

[@balthazarbeutelwolf9097]

did it without knowing/remembering the trick: 54 minutes; but I'm usually no better that half Simon's speed, so I suspect the trick didn't matter much

[@HunterJE]

25:31 It's possible to do better than 235 here - whichever cell has the 5 is going to index to the 9 in the 29 pair in column 5, which means the "23" half of the domino is in the same row as the 2 in column 5 and so must be 3, which not only turns the 235 in to a 35 pair indeed resolves it since there's a 3 clue in box 9...

[@siyuanhuo7301]

Not only that, there has to be a 7 above that pair as it's the only high digit available for that cell and that gets more digits ib

[@siyuanhuo7301]

In*

[@RealCadde]

25:45 Please, R9C9 cannot be a 3 due to the 3 being around the circle in box 9. Therefore, the 9 cannot go in R9C3. Also, there's a weird relationship between columns 5 and 9 in rows 8 and 9. A five has to appear in column 2 and 9 in some arrangement. If R9C5 is a 2 it means R9C2 is a 5 and R9C9 has no possible value. If R8C5 is a 2, then R8C2 is a 5, which makes R8C9 a 3 by sudoku. Which makes R8C3 a 9 by the rule. 9 would also appear in R9C5 which makes R9C9 a 5. Which one could have deduced by sudoku as well. Either way, the 1-5-9 rule is really powerful when you have reduced the number of possible digits in the columns. Oh and since R8C3 is a 9, R8C1 can no longer be a 3... So you get all sorts of a flurry of activity... If ONLY you'd realized that R9C9 can not be a 3...

[@Draenith933]

This was on the easier side when you understand how the 159 rule works. There were many strings to pull at the middle of solving. I enjoyed it! Keep on going kid!

[@josephprozinski9311]

There are four 1s, 5s, and 9s around circle clues in the finished puzzle. It's just that one of the circle clues does't have the fourth 9 on it. So the title is "correct"

[@joubess]

That was a fun puzzle but a lot more challenging than if I had realized the low-medium-high number placements earlier! Excellent puzzle GabeyK9!!!

[@tommmyyyy11]

ive been watching you for Months now.. I finally subscribed today to help you push for 500k :D

[@baedric._.7721]

Clicked just to disliked. Haven’t even gotten past the ad and I’m clicking off

[@Grandy_UiD]

Never done an index puzzle before, so I was in way over my head.

[@mallomon]

There was a secret, hidden fourth 9 in the clues! The 247 clue ended up having a 9 around it also, so it could've been a 2479 clue and would've worked the same.

[@robbrown5158]

I came to write this but found your comment

[@maljamin]

The intro title is incorrect: says the puzzle is by Aad Van De Wetering

[@tangrybird04]

42:41 for me…I don’t know if I’m just getting better at variant sudoku or the puzzles on the channel have been approachable lately…but I know if this puzzle was featured a couple months ago, I would’ve just filled in all the pencil marks and would’ve gotten stuck 😂 Edit: I should say well done to grkles and grkles jr. 👌

[@benwhite7317]

Anyone else catch at 0:10 that they use Aad van de wetering name instead of grkles and GabeyK9?

[@tobyonatabe2601]

Came back here after solving the sudoku within 3 hours, to watch you solve it 7 times faster! I love these kinds of sudokus, which both beginners and experts can enjoy solving.

[@rebeccahughes8734]

Happy Birthday, Megan! :)

[@tchpowdog]

I'm a programmer. I understand the indexing part, but it's not really an intuitive comparison to code language indexing. Indexing in programming most often starts at 0, not 1. Also, indexing an integer is rare, which can kind of be confusing in and of itself. For example: If I have an array of integers called "myIntegers", and index 3's value is 6, this means the FOURTH item in my array is "6". myIntegers[3] = 6;

[@nescirian]

I think someone made a quip about this appealing to programmers once and now CtC has to mention it every time this ruleset comes up.

[@tchpowdog]

@@nescirian yeah, I've heard Simon say it a two or three times. So I just finally decided to comment.

[@davidkomai]

This was such a fun puzzle. I loved the logic I had to use to deduce what would work.

[@steve470]

30:19 for me - I think I missed about as much obvious stuff as Simon did. 😛 Great puzzle!

[@GianniBergandi]

Found the trick very early but somehow I made it hard to finish. 42 minutes for me, amazing puzzle :)

[@ericpraline1302]

Lovely stuff, 159 puzzles really are very intriguing and seem to unfold like magic. And I don't feel at all inadequate at the thought that someone less than a quarter of my age helped to construct this, no siree.

[@th.nd.r]

Wow!!!! What incredible setting, super impressive, beautiful deductions all around, so many X-wings and cute tricks everywhere geez. Great solving too, well done Simon! Can’t wait for GabeyK9’s next puzzle!!! PS: the 3 in the corner didn’t get its song!

[@Radagast1953]

I've been wondering, for weeks now, what "3 in the corner" signifies in Sudoku? I must've missed the video where it was explained, but I've heard it mentioned [usually in comments] quite a few times now.

[@th.nd.r]

@@Radagast1953 Simon has a tradition whereby, whenever there is a 3 in one of the corners of the puzzle, he sings, “that’s 3 in the corner, that’s 3 in the spotlight, losing its religion” to the tune of “Losing My Religion” by R.E.M.

[@Radagast1953]

@@th.nd.r Thanks for the explanation! When I googled it, Most of the hits referenced that song [by R.E.M.], but when I looked at the lyrics, I couldn't relate it to "3 in the corner". 😏

[@JemEklery]

01:01:30, excelent for me :D

[@Stephen-Fox]

That ending was really tricky to figure out - And then I had a slight misscan/typo unwinding making me think I'd done a logic error at the last step but a quick rewind revealed my error as a simple misscan/typo.

[@sake9164]

Been waiting all day for this.😊

[@Hertog_von_Berkshire]

Much harder sans-secret.

[@wokkawicca]

Did it in 45m without the trick, but I'm always slow regardless. It just made things a little more plodding because I couldn't see all the possible eliminations. You still use the principle implicitly to figure out some of the quads like 1289.

[@exodustx0]

I'll just say that I hadn't come up with "the trick" before or during my solve (indeed, it makes perfect sense once you see it!), but I did get a time of 32:53 and absolutely loved it. I was particularly enamoured by the encircled 3 in box 9, as I used it to disambiguate the 36 pair in box 7 (I already had the 1 placed against that circle, and I couldn't index a 9 with 3 on row 7 because of the 159 circle, requiring a 3 on row 8 against the circle). Truly a marvelous puzzle, and I feel like I got to enjoy it twice to boot, as Simon's solve was so different from mine!

[@stevesebzda570]

Here [@12:50], it's a shame you didn't see that 9 (of "789" in r7c1) couldn't be there [the "9" is around the circle in box1]. So, that "r7c1" cell is a 7-8. That puts the "1s" in only cols7&8 in that row. There's your x-wing on those "1s" you were looking at. [So, there can't be a 1 in cols7&8 in row1 of box3 up there ] Now, up column1 are "1578." [But r1c1 CAN'T BE a "7or8" -- making it a 1-5 [The 1s are in row5 of box2, btw , from the 1s in boxes5&8] But that "1-5 in r1c1" is either self-referencing a 1, Or it's 5 referring the 1 in col5.. [So, either way, THERE'S A 1 THERE] That shifts that "1-4 circle" clue to have its 1 in row2 [And because of the 1s in "col6 of box8," the 1 has to be placed in r2c7 -- that makes c1r2 a 7] That's going to shoot down col1 to that "7-8" making it an 8 , placing the 1 in col8 of that row. There was your x-wing at the beginning though . Good job lol 😂😎☕️

[@AaronTeetor]

"If you are a computer programmer and you're new to variant Sudoku this might be a good one to try" Hard disagree. The 1 indexing (as opposed to the normal behavior of starting to count rows/columns at 0) always throws me off and I have to redo the puzzle three or four times because of off by one errors. Still can be fun, but man is this the hardest variant for me

[@ZooksterG]

I didn't know about the trick mentioned in the video. Solved it in 29m24s. The trick would probably have saved me several minutes.

[@drexel923]

My first time doing an Index Sudoku and it was fun. Took for 41 minutes though cause apparently I can't count columns correctly LOL

[@chocolateboy300]

I finished in 37 minutes. I really liked this puzzle. It felt quite technical in the solve, which I struggle with doing. You really have to pay attention to pencil marks and potential pathways. Great Puzzle!

[@tehcanadianbacon314]

Such a fun puzzle!

[@KingMagenta]

I’m only 13 minutes into the video. I did find several digits that Simon hasn’t found yet and I’ll try to explain how. Since there’s a 36 pair in rows 8 and 9 of column 1. The 1 in the 14 circle has to be in box 3 due to the index only being able to create a 7. We can determine that the 1 is in R2C7 because putting it in Row 1 breaks the 159 circle since there’s no space for the 1. Which means R2C1 is a 7. So because there is a 7 in column 1 now. R7C1 is an 8 or a 9. It can’t be 9 because of the 159 circle in box 6. So R7C1 is an 8, and R7C8 is a 1. You can apply this logic to R7C9. 3 can’t be there because of the 159 circle in Box 6. So 3 is in Row 8 in Box 9. Which means R8C1 is 6, R9C1 is 3, and one goes in R8C8 and R9C3. After that my brain can’t see any further because I’m not using the program. Haha. Edit: My solve probably would have been way different than Simons.

[@jensstalberg8968]

How hard it was without the trick? About 80 minutes... Actually not bad compared to how I normally do compared to your time. Well, I sort of used the trick of course, but not as deliberate as you did. For example I could realize that 1-2 could not go in C1R4-5 since it would give a double 1. So some sort of "grouping" was done even though I could not formulate the rule as good as you did. Lovely puzzle, I'm happy I managed to solve it. Mid way through the solve I was really worried about deadly patterns, I got way more of those than you did. :)

[@longwaytotipperary]

Oh neat! I just looked at the thumbnail - you used the actor for the show "Young Sheldon" (approximately 12 years old in this prequel to The Big Bang Theory TV show) The character, Sheldon, grew up to be a Theoretical Physicist. So nice tie-in to Gabey's age and grkles genius (literallly a rocket scientist?? wow).

[@rewolff2]

around 19 minutes you have a 36 Xwing in columns 57 row 45. You spotted the 3 going in box4 row6 but not the 6. Took you 13 minutes! I got that quicker than you... but then shortly afterwards I somehow concluded I had broken the puzzle, but checking my pencilmarks and your solution it seems I was still on the correct path.

[@kolkflor]

Can confirm, it's a lot harder to solve this without knowing about the trisection of the indexing. Solved it in 63 minutes, so about 30 minutes slower than Simon, while I'm usually only about 10 minutes slower. Brilliant puzzle though. :)

[@EchoMirage72]

Just from the rules, and the opening move, r2c7 should be a 1, which makes r2c1 a 7.

[@Slayer666th]

Did this puzzle without knowing the trick of the small, medium and big number per block… took me 150:49 min, so exactly 2.5h. Damn this was hard.

[@jussikuusela7345]

I tried, tried again, and ended up just watching the video. That happens a lot lately. Maybe it is the COVID or then these sudokus are just evolving completely out of my grasp. Maybe I will try to do the GAS of the weekend.

[@peterli100]

While solving the puzzle without knowing the secret doesn't make it harder, it is true that some of the deductions could be made earlier. However doing blindly would make the logic more linear and possibly more beautiful! Anyway, it is a very beautiful and approchable puzzle!

[@TheAnaCarolinaVideos]

I didn’t understand the trick, and I think that’s why I also didn’t understand why in R5C8 there is a 7, cause we can’t put a 8 in R5C7. Did I understood something wrong? Can somebody help me?

[@averygaron994]

65 minutes for me. I normally don't attempt puzzles that have videos > 30 minutes, so I'm glad I tried this one. I didn't know the trick and found it got fairly difficult pretty quickly, and had to work a lot harder to get digits after the initial 1/4 in row 6

[@stijnr2000]

I did not know the secret, nor did I discover it during this puzzle. It was especially the start which was a lot slower for me. I wasted a lot of time trying to figure out complicated patterns of the shared digits in the squares. Until I found out the question I should have been asking is, 'where do all the 1s, 5s and 9s go?' This gave me the same 1 as you did, but it took me 20mins probably.

[@iain_nakada]

16:10 Guessing he won't see this, but I've seen Simon miss a trick more than once due to eliminating corner pencil marks that are still useful. Keeping the '3' in the corner in these cells even when the central marks have been added (367) allows placing 3s in the corner of R6C2 and R6C3. Not critical here but has slowed him down a lot on previous occasions.

[@meerjos247]

The digit 9 was indeed missed in the circle 247 But apparently still solvable So possibly not a misprint, but pure evil from the editors!! :-)

[@dhruvjain3153]

It was my first 159 sudoku, so I didn't know the trick. Nonetheless, it took me roughly 95 minutes to solve this one. I absolutely loved the puzzle.

[@christianbechhenriksen898]

Very good puzzle! :) It took way too long for me (80 min including lunch :) ) But I managed to solve it without any help, and I enjoyed it :D

[@Adrian_Grey]

Simon: *has literally 3 squares left to fill* Simon, every day: "I think we're finishing off...." 😆

[@jeroenmathijssen7996]

63 min and done. me just pencilmarking the whole place first before actually making deductions ..

[@PhaseOG]

I saw the title and thought that it must be an approachable if it was made by a 12 year-old. 15 minutes go by and I’m still stuck with no digits. Arrogant me got a good lesson but was able to finish it in 50 minutes. Good job grkles and Gabey!

[@Kurgosh1]

Three hours. This one felt really hard, but I see a very short video. Must have missed a significant trick. (And it wasn't the 'secret.' I figured that out fairly early.)

[@micheltordoir7734]

I didn't use the trick deliberately, in fact didn't think about the 3 levels of digits. But in the same time I could see you can't have a 12 or 89 at the same time in the boxes. So I don't think that knowing the trick makes it easier. Quicker for sure.

[@victormanjarinsala2253]

Gorgeous logic, flawless solve path. I loved it!

[@Gonzalo_Garcia_]

13:38 for me. Great puzzle, and knowing the story behind it makes it even better!!

[@KyleBaran90]

Since each 159 box needs a low, medium, and high digit, I wonder if anyone has mixed it with Entropy Lines yet...

[@severnsevern580]

The 4th 9 is from the name "GabeyK9". Always wondering how these puzzles are created?

[@waluigi5848]

This was extremely hard for me, but I am pleased to say that I managed to solve it without any hints. Over the course of several days, haha. Very interesting and unique rules.

[@mirekchytil903]

Great puzzle, congrats :) I must say, the index cells really add a new dimension to the sudoku puzzle :D

[@VenomMorph]

13:18 1's in B8 are in C6, which forces 1's from 1-4 clue at the top to B3, where 1-5-9 clue resides

[@claudioestevez1028]

If I counted correctly, there are four 1s, 5s, and 9s adjacent to circles. One 9 is hidden, also a 1, but two circles share a single 1 so you shouldn't count those twice. Could this be the reason for the title?

[@nahblue]

my time 59 minutes. But with some hints after 25 minutes of puzzling. The 159 secret was super useful on this one.

[@datboiagain9341]

01:38:34 First time i try to solve a puzzle on my own. I have to say that wasn't an easy task, expecially without the secret! Much love from Italy♥

[@DarrenNakamura]

Got it in 47:07. I didn't ever feel like I had a strong grasp of where to look next, just kept plugging away until I got somewhere.

[@scottmcinerney9817]

I'm not there with solving a puzzle like this but there was one number that I saw a bit before half way into his solve that I saw clear as day and he didn't pen it in until near the end of the video. I tunnel visioned so hard on that 5, I could hardly even hear the logic for all the rest of his solves. Still enjoyed the vid though.

[@BeheadedKamikaze]

Your opening banner still shows Aad ven de Wetering, leading to much initial confusion with the video's title :(

[@ELStalky]

Solved it without knowing the secret, it was hard but still doable. Nice puzzle

[@lorijohnson773]

The missing nine in the title appears in row 4 column 4. So they are all there, it was just hidden. Thanks for another great video.

[@solfeinberg437]

I've broken the puzzle twice and started all the way over the second time. I'll come back later.

[@emilywilliams3237]

I really love that you featured this puzzle, Simon, not only because it is such a good puzzle and made for a fun video to watch, but because it is yet another example of the encouragement that you and Mark have given to many debut setters by doing their puzzles. And not only to those whose puzzles get featured, but also to those who are thinking that maybe they could possibly create a sudoku puzzle. Even if they never get featured, they had the glimmer of an idea that it might be something fun to try, and they tried it. CTC deserves all accolades that will come your way upon reaching 500,000 subscribers in part for this very reason - that you are such catalysts for not only the good and great among the sudoku puzzle makers, but also for the novice makers and solvers. Thank you so much. (And thanks for this video - as always, very fun.)

[@gideonmaxmerling204]

took me 29:09 I am confused how simon's time is longer than the video's time, did he forget to hit pause during some phone call?

[@drtv2426]

It was definitely harder without the trick, or maybe it just took me a long time to spot some things. In the end I managed.

[@SsSHardt]

That X-wing of 36 was just hurting my eyes for sooo long =) GJ tho

[@piarittersporn]

Wow! 12 years! Great. A really wonderful puzzle.