The Return Of A Sudoku Genius

[@81Cells]

Bastien here. Thank you Simon, I am glad you enjoyed the puzzle! I am going to talk a bit about a couple things you missed but please don't take this the wrong way, I think you did very well. The main things you could have done differently were: - Immediately after you spot the initial trick and write down R4C4=6 and R4C6=4, R5C5 is a naked single. It is absolutely not necessary, but I thought it was nice and I was hoping you would see it before filling the rest of row 5. What can I say? I am very much into naked singles. - The four large cages all need to contain 357 and they occupy exactly four rows. You could have used this fact to get rid of these three digits in the top four cells of column 5, eventually revealing two quadruples in column 5 (1289/3467). This was the intended way of solving the 19 cage, but what you did was of course perfectly fine - and probably faster. An additional remark: uniqueness-based techniques are very powerful on this puzzle, due to the geometry of the giant cages. There are several places where you can use them to speed up the solving process. This sudoku is actually a good illustration of how you can design a puzzle to have uniqueness-based solving steps as the intended solving path - which is not what I did here because I had something else in mind, but I could easily have taken advantage of it. I think that's all. Thank you again for featuring the puzzle, and see you next time - hopefully in less than four years.

[@pedrobluis]

Simon has been a little slow tonight 😁

[@tabularasa0606]

It was a joy to watch Simon solve it. Beautiful puzzle.

[@chaotix37]

This is not a sudoku, This is a masterpiece of art. XD

[@Xeridanus]

Was it actually a wolf or an elephant or something else?

[@alexwells8923]

Isn’t it titled “the wolf” in the top right? Or am I missing something...

[@LexicographicalPedant]

I just realised, the difference between a normal person like me, and a person like Simon, is that when I complete a puzzle, I’m proud of myself. When Simon completes a puzzle, he’s proud of the puzzlemaker

[@misharatkevich9808]

Well, it has to be a good puzzle, too... :P I'm not good at being a Sudoku guy... instead, I'm a Portal fan. You better believe I gave my screen the open-mouthed stare many, many times playing Portal Stories: Mel, or some of the better workshop maps by people like Mevious and Mikeastro. I guess if I were recording at the time, I, too, would be all like "this puzzle is GENIUS". I remember rushing to tell my online friends about "Amigo" (from Mevious) as soon as I solved it, cause that was so, so great. "Normal" puzzles, even harder ones, do not always elicit that reaction. "OK, I solved this, cool, what's next?" It's when there's some creative trick to the solution that it really sticks in my head and becomes a moment of wonder. So yeah, I completely understand Simon's reaction! ;)

[@srpilha]

@@misharatkevich9808 You just reminded me I _still_ haven't played Mel, and it's getting to unforgivable levels of delay. Praise from a fellow crypticcracker is a strong argument to do that this very weekend!

[@misharatkevich9808]

@@srpilha Play on advanced for the full puzzle genius and good luck. :)

[@LexicographicalPedant]

@@misharatkevich9808 What you said actually makes a lot of sense! In fact your anecdote reminded me that I have done it too, I just needed to think outside of Sudoku. I am a Computer Science student. I often marvel at the questions that my professors set for exams. I think of them as puzzles, and often find myself staring at my screen at the beauty of the question which guided me to the answer!

[@moonglum101]

@@misharatkevich9808 Portal? Are you talking about user maps on Portal? I didn't realize there was such a thing. Portal? Portal 2? Both? I have both games but wasn't aware of user maps. Mel is one of the maps and it's good?

[@bobblebardsley]

It has occurred to me over the past six months that sometimes when Simon spots a piece of logic and says "it's beautiful, it's just beautiful" he has in fact spotted something that was never part of the intended solution path and the beauty of it is purely and entirely his own. I think that's partly why it's so compelling to watch these solve-videos without necessarily ever attempting the puzzle.

[@bryanw2961]

I like how when the solve is going well Simon says, "WE'RE cooking with gas" or "I think WE'RE going to crack it". But when things are going poorly, it's things like, "I've done something wrong."

[@timbates6309]

Simon; Seconds after placing a digit in the grid. "and now I'm stuck". Within seconds he's off and running again. To quote a line from one of my favorite movies, The Princess Bride. "You keep using that word. I do not think it means what you think it means".

[@philm5872]

Thanks CTC! 2 months ago I couldn't do a simple sudoku. Now I'm doing chess sudokus and the 2 miracle ones!

[@Kelters]

Yes. It is like a University crash course in Sudoku solving. As you get better, you ought to go back to some of the earlier puzzles (there's a link somewhere to a spreadsheet with links to all of them) and check out how much you continue to improve. :)

[@philm5872]

@@Kelters cool. Good idea!

[@TheRealSavageGentleman]

Simon, you were staring at the 4 & 6 pair in column 5 for a literal 4 minutes with that, you could have figured out that 28 cage in about 20 seconds

[@Dwestiny]

simon clicking on the 4 at 29:44 while looking for a breakthrough and proceeds to solve the 5 in row 9 broke my heart a little edit: mousing over it too hahahaha

[@bristolrovers27]

Great puzzle I suppose it would be unrealistic to expect Simon to look for the simple route through, but great to see his enthusiasm for such elegant constructions

[@dkalambokis78]

He actually rediscovers Sudoku (aka his passion) every single day! That's a blessing

[@BlueCyann]

One of those puzzles where I'm super, super proud to solve it in less than 3x the video length. That really tested me, looking forward to seeing Simon's talent for cutting through the tangles efficiently. This was very, very enjoyable.

[@PH34RB]

Seeing Bastien in the book's contributer list yesterday had made me miss him. Glad he's back, this puzzle was a blast!

[@arturslunga3415]

Me 3 months ago: Couldn't care less about sudoku. Me now: Ah, wonderful use of the negative knight's move constraint! *puffs cigar*

[@rossylittle16]

Loved the puzzle. This channel has been an amazing thing for me. Cannot be more thankful to the channel as it has kept me sane while suffering with severe health problems in the last few months. Thankfully my brain works but nowhere near as good as Simon's. I love trying to solve these puzzles then watching the video and looking at where I lost time by not seeing the obvious (always called that puzzle vision personally when you cannot see the basics). Just wanted to say thank you for the channel and that you have kept me going.

[@HonkeyKongLive]

Ah yes. Wolves, peacocks, and anteaters. Easy to get them confused in the wild.

[@moonglum101]

Especially those pesky anteaters with tusks!

[@Xanafear]

Your excitement, Simon, is contagious - this was a delightfully fun puzzle to watch, especially as I have no time or place to work on a solve for this myself. Thank you for sharing your joy in the puzzles with us all!

[@uimraynefall2582]

This is the first puzzle I watch where I was thinking "Why don't you see this!" It was all about the symmetry. Fun!

[@verstrickt.und.ausgerechnet]

This puzzle was incredibly elegant and I enjoyed it tremendously! Thanks a lot, Bastien!

[@mritty115]

20:01 Simon staring at and not seeing the 7 in R9C5 affecting the 79 in R4C5 just makes me feel so much better about myself when it takes me what feels like hours to see something obvious.

[@matthewlyons6544]

I came to the comments to find someone else who noticed!

[@seyedmatintavakoliafshari8272]

For a sudoku enthusiast like me, this was simply brilliant! Very entertaining, I enjoyed the creativity of Bastien into constructing this piece of "art". Definitely extraterrestrial quality from Bastien! Bravo to this channel.

[@clffliese26]

I said this in a recent video: You need to do some of these as live feeds so I can stop yelling at my phone, "Cell (some number) in box (some number) is (some number)." Please, keep people from looking at me like I'm some kind of lunatic, I'm begging you! 🤣 On a more serious note, I've been doing Classic Sudoku for years, back to a time when Dell puzzle magazines were calling them "Magic Number Puzzles." I've done some Killer Sudoku and a couple of Chess Sudoku puzzles. I've enjoyed all of them, but, I have to admit, the Thermo Sudoku puzzles scare the crap out of me. The bottom line is, I, really, enjoy your channel. You and Mark make, even, the ones that terrify me look fun. Thanks, guys. P.S. Simon, when you're on your laptop, you need to adjust the lighting because your face is in shadow. If it were me, that would be a good thing, but not for what you're doing.

[@ceevio_art]

Simon, as long as the audio is good, you can sit in complete darkness for all I care. Cliff, you got a man-crush?😁

[@johk2293]

For me it looks more like a dragon from Chinese culture. Same mustache and stuff

[@space-raider-system5828]

I see absolutely nothing except a very calming channel that I now enjoy when my anxiety spikes haha

[@slomopanic]

I have no idea what you can do with this info, but i watch the videos while im having dinner. Thanks for the entertainment!

[@jokevv1]

Looks like an elephant to me. Don't know what that says about me ;-).

[@ilonachan]

Wow, now I can see that too!

[@philipnewmansudoku]

It's intended to be an elephant, according to Bastien's blog. (I think it looks like a lion, if not for the grey coloring.)

[@moonglum101]

How is it anything but an elephant? I can't unsee the tusks.

[@fade2dblack]

I went with walrus.

[@akemi12]

I see a tiger's face

[@NiekBoersma]

Congrats on reaching the biographical stretch goal on kickstarter! I was really rooting for that one :-)

[@Obnoxiouspatriot]

Your explanation on how you got the numbers for the 38 in the top right was phenomenal. Thank you!

[@chrissolnordal9421]

I need help from Simon on this one: once he said "look at *this square" (which was R4C4) I was able to complete it. But for a change I didn't over-pencil-mark, and was able to restrict quite a lot of squares as a consequence. I found that whatever was in R2C1 was also in R3C4, and consequently in either R1C7 or R1C8. Which meant it was a number that was in BOTH the 22 cage and the 38 cage, and so was either 3, 5 or 7. And because of all the symmetry, there were three other similar deductions that limited options. A very fun puzzle as usual, thank you!

[@fbrume]

Very elegant construction, especially with the way the top killers folded back on themselves. There was a way to get the 16 earlier. In the top six cells, one cell was a 125 and no other cell could be 1, 2, or 5, so the 16 had to contain two of those numbers, making it a 2-5-9.

[@alexwells8923]

“Stop resisting!” Ahhhhh that was magical! I was feeling every few minutes “ah he’s done it now!” And then you were confronted with a myriad of parallel doubles and triples! It kept pushing and pushing you! Very fun to watch, thank you!

[@stevenmiller5400]

I really appreciate the way you let us hear more about how you figure the number combinations.

[@Wecoc1]

12:34 Not sure if it's useful but r4c5 can't be 3 or 7 since it appears in both sides, and because of that "round the clock" effect it would force that digit in both c4 and c6 on box 2.

[@cheezunriceramen8995]

It's cute when Simon goes in to star-struck fan mode

[@jdyerjdyer]

Absolutely brilliant puzzle! Loved solving this one! Simon found a few simpler logic pieces and a few harder ones. Even though the start was fairly linear, the beauty in it was a feat to behold!

[@Kelters]

I'm pleased to see the start off I made was exactly as Simon right up until he also got stuck after the 17 cage. I was feeling quite chuffed. However, that is where I had to peek at the video. Bobbins!

[@francoisduez601]

Finally, I thought it would not come tonight 🤔 Do you think I'm addicted ? 😁

[@ilonachan]

We all are, my friend.

[@hutto1jm]

I know I am

[@jeffreygi]

I can't even see any of my DVD collection. (Not complaining)

[@Tahgtahv]

He mentioned the delay on Twitter, and in Discord. May want to join one of those places if you can. Apparently the upload took longer than expected.

[@paulmdt1]

School half-term break here in the UK, so Simon is back on holiday again (with his laptop).

[@danieltaber4924]

One of the things I did was color in the 6-square cages at the top. Thanks to the geometry of the puzzle, not only could you divide each triangle into two triples distinct triples, but one of that triple was a directly identifiable clone from one of the other triangle! (For example, R1C2 = R4C3, while the pair R1+2C3 mapped onto the pair R4C1+2. This pattern repeated through all of the triangles, which both made the bouncing at the beginning more intuitive and helped close out the end more rapidly.

[@rubenalonso5537]

This is one of the most gorgeous puzzles i've ever seen

[@glennmelven3414]

Getting all those triples and then eliminating other candidates from cells took me a loooong time. I couldn't imagine doing this without pencil marks.

[@Raven-Creations]

What an absolutely brilliant puzzle. I nearly didn't attempt it, because it looked like I was going to need a lot of mental arithmetic, and I wasn't really in the mood. I'm so glad I gave it a chance. I cottoned on quickly to his little game, and was sucked in. Even so, it took a lot of teasing apart, needing careful policing of pencil marks. Initially I was slightly disappointed that the 28 cage in box 7 broke the symmetry of the logic, but I'm sure that was deliberate to make us work hard for the finish.

[@brucerose4383]

beautiful .. needed Simon's primer on the "6" and "4" in box 5 to get started .. then just lot's of fun ..

[@pulos42]

"we know all of the digits 1-9 equal 45". Did that make it onto the bingo card yet?

[@S_Black]

New stretch goal: updated bingo card that includes "bobbins"

[@Dragonatrix]

It's gotta be the free space, surely?

[@NoodleKeeper]

@@Dragonatrix the free slot:1-9=45

[@totalcoward]

This puzzle requires more mental fortitude than I currently have available to me. The killers in the top left and right of the grid are very interesting construction

[@Dysiode]

This would be a hell of a puzzle to do with a pencil, but it's just so gorgeous. What if there's a section of the book of QR codes to puzzles like this?

[@UberHummus]

To hear you speak of this man’s speed at sudoku gave me the shivers

[@CroixMedia]

The grid at around 20:55 is so satisfying. Such a good puzzle.

[@Zacks-Channel]

It has to be an elephant with tusks, right? Great puzzle! My only question is, if a number repeats in both the 22 cage with 6 cells and the 38 cage with 6 cells, doesn't that guarantee that number doesn't appear in the remaining cells in row four on this puzzle? For example, 3, 5, and 7 appear as an option across columns 1, 2, 3, 7, 8, 9 in row 4 after we pencil the possible values for the two cages, so does logic tell us that 3, 5, and 7 can't appear in columns 4, 5, and 6 if that's the case? Thank you for another fun solve!

[@gweria]

If you're still taking suggestions for the Puzzles to add to the book I'd like to suggest the Cave Fillomino puzzle by Jesper Josefsson. That one was sublime, and you seemed to enjoy it a lot as well.

[@blackrider7412]

The more videos of you solving puzzles I see, the more I realize how bad in them I am...

[@IlSharmouta]

Well he guides you through his logic every time, so slowly but surely you can get the hang of it if you want to.

[@gms8994]

This was one of the more fun puzzles to watch Simon solve. Absolutely wonderful.

[@stevieinselby]

12:50 - what you can say is that because both the 22 and 38 cages have to contain 3️⃣s and 7️⃣s, the top 4 rows already have their full complement of 4 3️⃣s and 4 7️⃣s, and so r4c5 has to be 1️⃣9️⃣, and by the same logic the cells above in box 2 must all be from 1️⃣2️⃣8️⃣9️⃣ as they still need to make a 4th appearance in the first 4 rows.

[@Wecoc1]

It reminds me the baddies in Space Invaders

[@danielrhymer1762]

That was my initial thought as well

[@ipudisciple]

True, but TBH pretty much any symmetric pixel pattern looks like a space invader!

[@Morgan423Z]

Space Invader sudoku rules: You must slowly move alternatively left and right and periodically slide down in your chair while solving. If you can't solve before falling out of the chair, you lose.

[@clffliese26]

It's been so long since I've played Space Invaders, I didn't pick up on that. I didn't see a wolf, either. The only thing that went through my mind was, "I'm glad I'm not solving that on camera."

[@dma-rising8876]

My thought too

[@grumpkingames]

1:08 - When I first looked at the 22 and 38 cages, I was like "dang! Such tight constraints right off that bat, this is going to be easy!" But it had me a little stumped for a while in the middle! Not sure how helpful it ended up being, but something I noticed very early on was that C5 R1-4 had to be a 1289 quad, because we had 3 instances of each number showing up in the top 4 rows already when you counted the cages and the 2 diagonals in box 1 and 3.

[@swearwolf.werewolf8049]

Anyone else come here when they're having a mental breakdown just to feel the seretonin radiating off of Simon when he starts figuring things out? Anyway it helps keep me from being a depressed little hoe so thanks for existing Simon.

[@SimonSideburns]

I don't often complete puzzles that are solved by Simon but even including a nap of unknown length I'll take 1:17:07 to complete it. Had a few gaps of unknown length also due to not spotting the next step, but I'm quite pleased with myself.

[@ZoraZoldier]

You have featured a lot of very cool and beautiful sudokus before, but this one was by far my favourite yet! :D

[@sandalsfgc]

your enthusiasm makes this so enjoyable for me

[@zsaadi]

Would it be possible do to a Q&A video? I've got a few questions and I’m sure others have some as well, possibly the same questions. For example; What is a naked single and how can you spot it? How can you determine whether or not a puzzle can be solved using symmetry?

[@wokkawicca]

In general a naked single arises from an interaction of row, column, and/or box that eliminates all but one possibility for a cell...a row with 1234 and intersecting column with 5678 implies 9. The advanced rule-sets allow for more devious naked singles than in straight sudoku, of course. Whenever you see given or placed digits forming logical groups, try to spot where those groups might interact. If there's a row/column/box that's over half-full, ask where the missing digits might go. If you have tons of pencil marks, periodically scan each digit for uniqueness in each row/column/box. If those fail, un-pause Simon or Mark, then smack yourself when they spot it immediately.

[@Qazqi]

I noticed something at the beginning that you'll be a big fan of: 3, 5, and 7 appear four times in rows 1-4, so there's technically a jellyfish of sorts (though using cages instead of only rows/columns): i.imgur.com/xav8mDd.png

[@nullreference0]

Don't usually watch during the day, but I saw it on my feed and can't resist!

[@AEPMUSlC]

Nice puzzle! Pretty straight forward and not impossibly hard.

[@AndrewMabon]

At around 20:55, another way to look at it is to wonder whether R9C6 can ever be a 3. If it is, there cannot be a 3 in the 17 cage, which we already know must contain a 3. Hence, R9C6=2.

[@HalfBakedLunatic]

That was a big ol' heaping plate of spaghetti logic! It all made sense, but following each strand took amazing concentration. Nice puzzle!

[@ultimatecalibur]

At 27:09, he placed a 4 that disambiguated the column 5 46 pair... which would have let him figure out the the28 cage much sooner. He actually did the cage in reverse order after taking a roundabout 3 minute detour.

[@yichen6313]

43:54 for me! Not bad :D I love all the logics in this puzzle

[@dragonborne3277]

LOL "No, stop resisting!"

[@LightDhampire]

Another way to look at the 28 cage was that the bottom left digit was a minimum of 3 with the 1 and 2 in row 9. With the 8, the 4,6,7,9 possibilities cannot include the 9.

[@theunrealthomas4109]

This are my addiction😭😭 I keep on coming back

[@stevesebzda570]

@22:41 OMG. (Before I immediately looked on the other side for a vertical triple in column 3 that's going to affect that 28 cage below the same as on the 17 cage below. There is one ) But I'm seeing here, in row 3 still there's a second triple that's going to make the other "eye" an 8. [I saw the Constructor's comments that there were a couple quadruples or something somewhere being the intended route (but he still liked the solve) but I have a feeling this is how great a job he did on this puzzle] You could have two eyes staring back at you , Simon. (While still symmetrical sort of) That's how great a job he did. I think anyway. Is there another triple on the other side in row 3 here ? [[ a "569" ? ]] Fantastic again (And I'm only at this part lol ) [[ 26:11: the "8" is there (in the other "eye") ]] Fantastic job solving, Simon. And, Constructor. @6:37 Interesting.. I didn't really realize or think about it (124 being the only way to add up to 7 in three cells). Cool, thank you [[ I lost my grid, that's why I'm back here, Btw, (filling it in) lol ]] 😂 [[ But I had to comment about that fantastic 569 triple I possibly saw along row 3 making that other "eye" an "8" though. Hope I'm not wrong ? Lol 😂 ]] Very cool

[@Turidus]

The middle box is so close to being a magic square! I am sure that it is quite impossible to set this puzzle in a way that leads to a magic square, and that Vial-Jaime spend quite a lot of time trying to get it to work before having to give up.

[@OverkillSD]

YOU WILL BE UPGRADED Looks like a cyberman to me.

[@benvansteijn7709]

have you ever thought of getting an eye tracker I think would be very interesting to see your eye movement when solving

[@ceevio_art]

LOL. You're probably right, but its entertaining enough watching his cursor hover over naked/hidden singles (as we all yell at the screen) while he mutters to us/himself: "I feel like I'm missing something here?.."

[@GreatUSTreasureHunt]

Eight bit Optimus Prime. But with ten bits. And where does the Matrix of Leadership go? It goes here!

[@Ennar]

It's literally 81 pixels.

[@Jodawo]

Was a very symmetrical puzzle it actually kept you on its path and didn't allow you to stray.

[@robertyeager6826]

I recently saw your videos and started doing the puzzles. I even took a stab at creating one. I don't know the difficulty level of the puzzle, but was wondering how I could send it to you guys. I don't see any type of link to do so. Thanks.

[@alternativeglasto]

I git as far as filling in the 22 and 38 cages, deducing the diagonals, but then got stuck and didn't see the break-in in r4c4/c6. It's very clever!

[@kristenswinton7785]

Fantastic puzzle!

[@jonbrowne8334]

Brilliant solve!

[@job8]

This was so beautiful...

[@wren4077]

How long do you reckon it takes for you to remember the certain size of killer cages adding up to certain numbers I know its practice but I'm just wondering, about how long is it weeks months years? all i recognise is what 1 to 9 add upto what 9 8 7 add up to and what 1 2 3 add upto

[@adamheywood113]

The 22- and 38-cages only have one possible composition. They each have three digits missing and the only digits that can be missing from a 6-cell 38-cage are 1,2,4. That's the only way to make up the remaining 7 in the remaining cells. Similarly for 22-cages, the only way to make three cells add to 23 is 6,8,9. So there's a 689 triple in Box 1 and a 124 triple in Box 3. That's all I got. Or you could just watch the first 90 seconds of the solve lmao

[@S_Black]

The 9 was restricted to Box 4. Which means there is only one place for it in Box 6. That would have resolved the 79 pairs a bit earlier

[@aloofmeatloaf1467]

Simon, please remind me what the digits 1-9 sum up to...I don’t recall what the number is after hearing it in every video of yours that involves sums.

[@ariondys]

it gives a lot of insight into puzzle setting

[@londonbobby]

I thought this was going to be much harder (based on 30 minute video) so I nearly didn't try it. But then saw the R4C6 and R4C6 thing almost immediately and it solved very quickly after that.

[@vikingslayer34]

That wolf has a lot of numbers tattooed on his face. You just gave Post Malone an idea....

[@rebmcr]

I figured out quite early on that these coloured zones were equivalent, it was a great help with propagating changes through the grid: i.imgur.com/fXeRbI7.png Unfortunately it required blanking the dragon illustration.

[@rebmcr]

Looks like Mega Charizard X.

[@matthewender3473]

A good lot of symmetric logic! Took me 39:47. Skimming through the video, looks like I took a similar path to Simon, just slower of course :)

[@richardfarrer5616]

Whew! That was a workout. Still, I need the exercise.

[@senseialee]

a serious questiuon here: how can you spot the first restrictions so fast? it took me 20 minutes to figure out that there is just one combination for the six cell cages and you did it within a glance. is there an efficient way to know that?

[@jackieenois]

I got used to watch these videos everyday on 1.75 speed, now whenever I open and try to watch in normal speed seems link simon and mark are on slow motion.

[@Dysiode]

This is a great sudoku!

[@justacynic]

How weird. I ended up with a double X-wing on rows 2 and 3 for digits 37 and 59. And it checked out as correct. Huh. I thought the answer was very unique to lead to a double X wing where the digits entered didn't matter so long as they were inversed in the other column. Now its super unique because it had different placement for the 6s!

[@neilramsey1368]

I was also waiting for you to see 46 in col 5 for what seemed like ages but I was staring at 12 I had in R7 C1 for ages as well not taking any notice of the total for the cage

[@BryanLeeWilliams]

After 59 minutes I know almost everything there is to know about 1's,2''s,8's,and 9's there is to know. ...Except I can't put a digit in. I know the contents of the box1 and box3's non-caged cells, just not which digit goes where. I know some places that must have a 1or2 and a 8or9. Ah, this is so frustrating. I think I'm right on the cusp. But it's been an hour. I think I'll have to watch the video. EDIT: I stopped at 8 minutes I put in the 2 digits Simon was about to put in then put in another, then I ended up with 9, then more, then back to 9. Now I broke the puzzle. Can we change the rules of Sudoku so you can have two 5's in column 5? I totally agree with Simon that this is elegant. That thing with the 6 and 4 in row 5. I found that too, and was amazed by it.

[@maginpanic]

very nice puzzle :D not so hard for me as the most on this channel :P

[@Kelly-yd4bc]

Does he have these cage number sum posibilities somewhat memorized, or is there a trick I'm missing. I tried to brute force my way through figuring out the possible combinations but missed that 12356 sum to 17 and jumped straight to 12347 which broke my solution.

[@erickehr4475]

35:28 for me. It was tough but enjoyable. Annoyingly I was near the end when I noticed a contradiction and had to backtrack quite a way and redo it. My logic had been sound though, so I must have just accidentally typed a number I didn’t mean to in one of the cells.

[@michaelobille5447]

Can someone explain to me how he correctly placed the 5 in box 7 when there was still the possibility of there being a 5 in row 9 of box 9?

[@nishanthn4927]

10:10 I thought you were gonna point at the naked single in the centre...