Many thanks for posting this Anthony, glad you all enjoyed it. I should clarify that, while hand-made, it's with software assistance, that software evaluating the grid during the seeding process and identifying the solving steps.
I'd love to see more puzzles made in the same way if the result can be so impressive. Feel free to make more along these lines. I really loved it. There were many cases of cells that could be a given pair and evidence that the cell contained the digit that it couldn't be if you missed something subtle like the 78 pair in column 7, or 478 triple in the top left box to place the 6 in r2c4. Without placing that 6 properly, the top center box was impossible to break into by my normal approach.
I think I'm going to save this one until tomorrow. If Simon says a classic sudoku is stunning, I need a fully rested brain to be able to solve it and that's not happening when it's past midnight.
Sending my regards from across the pond in Denver, Colorado! Stumbled across the channel not too long ago and have been so grateful. Thank you both again!
My break-in was _completely_ different! The 4 cells shared by column 1, column 9, row 3 and row 5 contain a 59, 19, 89 and 18, which act as a kind of quadruple x-wing: column 1 can only have a 5 in those cells, column 9 only a 8, row 3 only a 9, and row 5 only a 1.
I almost immediately found an X-wing on 7s in rows 3 and 7 after placing a 7 in r5c6, but it doesn’t advance the solve much until later. I liked your solving path better!
My thought process when i solve sudoku is still too mechanical compared to this guy. I don't think i would have been able to find the x wings without filling the whole grid with all the possibilities. It's incredible how easy it is for him to spot these patterns.
Solved in 56:52, first time solving a puzzle from your channel without having to watch the video when I get stuck. First time using X-wings, Thank you so much for all the content, these videos are awesome.
I love the classic sudokus on this channel! The ones I've tried have been very fluently solved but still somewhat challenging. I got bored of classic sudokus few years ago but finding your channel has really made me enjoy them again!
Managed to solve in 08:35 // Another reminder, I think, that it's a good idea to actively look for X-wings and Swordfishes in these type of 'symmetric' sudokus. Thank you once more for the bonus content! Looking forward to more.
8:58 "Oh, I'm so stupid, so stupid." No, no you are not. That might be the first time I've ever found a puzzle entry faster than you, so allow me my pride! Honestly I'm amazed I was able to solve that. Something is finally sticking. Total time just under 40 minutes, as usual the hidden triple was a big problem, but I found it!
@eric vosselmans no he meant at that time of THIS video where simon says he is stupid. He is saying, "simon, don't say you are stupid as that implies you are saying that was an easy move to spot and I am very proud that I spotted this move. Dont take that away from me."
After a few bad starts I watched your solution. Afterwards I tried again and after filling in the obvious marks I worked the perimeter and looked throughout for rows where only 2 of a digit lived. I also found X-wings for 1 & 7. Going at it this way made the puzzle much easier to solve.
I never saw the X Wings. I quickly established that the 5s in row 1 were restricted to box 1. This immediately gave me two symetric tripples in boxes 1 (4-7-8) and 3 (5-6-7). From there, it was relatively clear sailing to the final solution. It was a fun puzzle with, as I now realize, two entirely different manners of reaching a successful solution.
Absolutely beautiful, thank you. At some point, I also spotted a swordfish on 4s which you didn't but, eventually, the result was the same. Again, thank you for the upload. Keep 'em coming, please.
I spotted the 3 x-wings before Simon, so I'm rather proud of that. Once the 478 triple forced a 6 into the middle top square, it kinda just unraveled from there. Great puzzle! I think I'm getting better at these.
Man! I'm so happy I solved it too. To be honest I tried it after watching this video and used the knowledge of 2/3 x-wing but I couldn't reduction of 478 triplet but after trying to find logic for I found another logic and eventually solved the puzzle.
44:22 solve time for me. I had to watch the video here and there for help but I got it. Without the video I'd have been beyond stuck. I'm still starting to learn all these more advanced patterns.
I think the easier way to spot the first 23 pair is from the geometry. c3r3, c7r3, c7,r7 must go to the three of the four empty spots c1r5, c9r5, c5r1, c5r9. the location of 23 in r5 further constraints to a 23 pair in c5 alone. That means 1 must go to c1/9r5.
At 15:00 Simon identifies the 478 triple. I have a question as to how he could then confirm the 6 in row two when one of the squares he highlights as 478 triple in that row does not contain a 4 ?
Well Simon , all i can say is BOBBINS. In C Am F and G. As you know, with these 4 incredible chords, you can actually play hundreds of songs songs.🎻🎺🥁🎹🎹🎸🎸🎸🎷🎶🎵🎼📯🔔
I spotted the 478 pair, but only after I had painstakingly spotted an X wing with 7s in R3 and 47. So by the time I got there I'd actually found a quadruple instead of a triple! 48 - 47 - 46 - 78 Still cracked the puzzle for me, but wow, took me much longer to get there!!!
This amazing puzzle gave me huge fits. I've gotten a lot better at sudoku puzzles, BUT there must be *something* basic about the proper logic to solving them that I just don't seem to understand yet. I say that because I kept going down logical paths that appeared okay only to keep seeing two same digit trying to go into the same row or column. I'm trying to figure out what I still don't know, but I still haven't figured that out. This puzzle is truly amazing and a learning experience.
I found two X-wings, but couldn't solve it. Edit: Missed the third X-wing. Then I didn't see the hidden pair (or open complementary open triple and hidden single). Eventually I solved it by finding a jellyfish.
Needed TONS of help with this one, but! I spotted that 478 triple myself in the first box, I just... didn't spot the triple that later caused in row 2. But hey, I spotted a triple, that's progress!
16:22 Only found 1 x-wing, but decided to pencil mark groups of 2 and 3 in a box which actually helped with finding triples. Now to see Simon's solve...
28:32 for me, proud of myself for spotting a few advanced techniques like the double X-wing and the interesting quadruple in r3c1, r3c9, r5c1, r5c9. I'm interested in what that pattern is called because I haven't seen it before Edit: Just watched the video, I never found the 478 triple so our solves were way different, interesting to see this great puzzle done a different way
I found something in addition to the X-wings shown in the video: in rows 3 & 5 and columns 1 & 9, you can reduce the four intersections (r3c1, etc) to the same 4 digits: {1, 5, 8, 9}, in ways that restrict those digits; I used that to place a 9 in r2c4 (since there had to be a 9 btw r2c1 and r2c9), and using the additional fact that r2c6 had to be a 2 or 3 (found after the X-wings) and the fact that 5 could not be at r2c5, I restricted the 5 in the top-center box to row 3 and used that to get the four numbers at r3c1, r3c9, r5c1, and r5c9. After that (and with the X-wings), the rest was relatively straightforward. (Of course, I only got all that AFTER erring and starting over!)
I found the same logic and even resolved it with the same trick with the 5. I was actually unhappy that Simon missed it in his solve, because more than anything else, I wanted to know what that kind of logic is called. It isn't a quadruple despite having four numbers. It behaves somewhere between pairs and X-wings without being either one. What's the official term for this pattern?
@@riluna3695 I found this pattern as well. I wasn't able to resolve it, though I was able to use it to resolve the 9's in box 2 r4c2&3. It was my getting hung up on this pattern that caused me to miss the hidden triple that Simon spotted and caused me to take over an hour to solve the puzzle. There's a guy on youtube here called Sudoku Swami and he claims the pattern supposedly and calls it the "Swami Quad Loop". th-cam.com/video/VyrTR0x6Xdg/w-d-xo.html
@@ericcrowell9493 Ooh, fascinating! Thank you for sharing that. A "quad loop" definitely makes sense as a name, and if he was the first to "claim" it, then props to him.
Ah man, I used that to solve it too and had never seen it before. I was hunting around for hidden triples and decided to see what would happen if I played with those. I was so excited to see that it worked. I really wanted to see how Simon would react.
That is exactly how I started the puzzle. I was a little disappointed somehow that Simon did a completely different solve. But hey, that was pretty too.
As you recently observed, after 7 in E6 it was obvious that a 7 could not be in any of the 16 corner cells ABHI1289. Because there was no 7 possible in the cells neighboring the central 3-by-3 square.
At time stamp 15:23 , how is it possible to resolve the 6 and eliminate the 4 from row 5? What would happen if the 4 was in column 3 in the top-left 3x3?
Do you mean column 5? At this point there's three cells in row 2 that can contain only 4, 7, and 8 (columns 2, 3, and 7), so there can't be another 4, 7, or 8 in that row.
I suppose you mean column 5, row 3? It's because if you have a 4 there, it would be 3 squares in row 2 that could only be filled by two digits (7 and 8) - which is not possible. Two clarify: if it was a 4 in column 3 in the top left 3x3 - what do you put into the 78 square in the top right box?
@@routhy46 Thanks for the cogent explanation. Makes perfect sense. But, as I've claimed in another video, this does not explain how he can claim this is a "478 triple".
@Rod Morningwood I see what you mean. I only have a guess as to why he uses the term “triple” in this case. Three cells in row two can only be the three numbers 478 collectively so it’s considered a triple (three cells, three candidates). I think the term “hidden triple” is used in cases where three numbers are already unique possibilities in three cells, but are buried amongst other candidates. In this puzzle they are not unique within the row because of the 4. But since 478 are the only possible numbers (they aren’t hidden), it’s just a triple. Am I still cogent?
I tried before watching the video. It took nearly an hour. I watched the video until 3.55 and was happy I didnt miss anything simple. Hoping to see if the xw7 is explained, as I really felt like I winged it.
There is an interesting quadruple in r3 c1&9 and r5 c1&9 as well. It didn't break open the puzzle for me but it being there right at the start did help me later on.
At 7:05 when you identified the first X wing on the 2's you missed placing a 2 in the last column on the 2nd row, I was shouting at you, 'it's there!!', but you didn't hear me. It's something I do a lot when the grid starts getting busy. I have another Soduku game that lets you highlight all occurrences of a number which I find useful but doesn't support proper Sneider notation so I've stopped using it. Does anyone else think being able to highlight all occurrences of any number is a useful feature to add to your web app? Which I love by the way. Thank you CTC.
C1R7 + C9R7 is a 239 only and rules out the 9. Then with the 8 in C4R8 we get a 23 pair in C5R9 + C6R8 which makes a 46 pair in C4R7 + C6R7. Slightly different approach.
World is in dire peiil! We need geniusses to save us all!! Crackling his Knuckles...right...but I need to solve this Sudoku first.... Stay save you all!
Near the end in lower left block, I didn't follow why 9 couldn't also be in the middle cell when you said it had to be in the middle column, top?? Good instructive video. Thanks. (Beginner).
Simon's looking at what numbers still need to be placed in row 7. It still needs a 2, 3 and a 9. In the cell you are looking at, where he puts a 9, he can rule out 3 because there is already one in the column, and rule out 2 because of the pencil marked 2's both in the box and in the column. Hope this helps.
If you have 3 squares that all must contain the same 3 numbers then they form a triple. The 4 MUST go in one of those three for it to work out so you can eliminate it from r2c5. אלה מורה
Question: I noticed a pattern I thought was interesting, The four cells in Rows 3 & 5, Columns 1 & 9, were limited to 1589 in pairs. This pattern restricted 5's in C1, 8's in C9, 9's R3, and 1's in R5. These restrictions got me to wondering. Does this pattern have a name?
Yes I also came across this and it was stunning! Haven't seen or heard of it before. Too bad Simon solved one of the corners early with his 78 trick. I was really hoping to see his reaction and explanation when he found it. Anyhow, if it doesn't have a name, I suggest quadruple X-wing.
Started the puzzle by finding the X wing on 7's, gave up shortly after. Watching Simon's solve: "Ah there is an X wing....on 2's!" and shortly after " Oh there is another X wing, on 3's!" Colour me surprised, nice setting with this puzzle.
A time of 40:29 for me, only because I'm still ABSOLUTELY RUBBISH at spotting triples. I got the X-wing on 2's and 3's very easily, the swordfish on 4's was easy to spot, but the 459-triple in column 7 took me far too long to spot.
Anyone else notice the x-wing on 7s? It made me wonder if there was a deeper tactic I was missing, since that was 3 x-wings. Well, whatever it was, makes me feel good that Simon must have missed it too if it did exist :D
I solved this in maybe 40+ minutes with first some very basic moves and then had huge troubles and colored paths for candidates. I didn't even find any triples.
I did find the triple in box 1. I did not spot the x-wings, nor did i get the 78 pair out of it after watching the video. This one's a bit too hard for me! Nice puzzle though.
Hoping someone can clear my confusion here. At 9:58 it is decided that because of the 4,6 pair that 8 must be in 2nd cell in the 5th box. He then places that 8. However, I thought earlier it was said that the centre cell of the 8th box (the cell 4 positions directly below where the 8 is placed, 1 above the pink box) could be "loads of numbers" at 8:14. Could someone explain how it was determined that this cell was not an 8? There seems to be no 8s anywhere else to confirm this "Couldn't" be an 8? Thanks
It could have been an 8. But the 7 could only go into 2 cells in column 5. Rows 89. The x wings on 23 in column 5 removed the possibility of R9 C5 being a 7. Forcing the 7 into R8 C5.
@@glennmelven3414 Thanks for your response. I see your logic, but I think I got confused because he solved that 7 AFTER he had placed the 8. He places the 8 when it could be either and his decision is only confirmed once the x wing confirms the 7 after. Or are you saying that he probably knew it was a 7, and just didn't explain it until after? Sorry!
At the time Simon places the 8 in the centre box it is the only candidate still available for that particular cell. (1,5,6,7, 9 are ruled out by other placed digits; 2,3 by the two x-wings that lock 2,3 pair into the top and bottom cells; 4,6 by these being the only candidates for two other cells in the column). I hope this helps.
Once the 23 pair is locked into the overlapping X wings, 3's are eliminated from the other cells in column 5. That turns the cells with 346 into a 46 pair, thereby eliminating the 4 from the 48 pair in r4c5, leaving just the 8.
I think there is an easier way to this puzzle... apart from the 2 and 3 xwing, there is a 7 xwing on row 3 and 7 which gives a 236 triple in row 9. With that, the rest of the puzzle essentially resolves
478 triple in upper left 3x3 box as a result of 478 in column 1 and row 1, could have made things simpler . A 23 pair in 1st row and column 5 , and 23 pair in the last row and column 5..
Simon has worked out that there are three cells in row 2 that are restricted to being 4, 7 or 8. Since there are three cells and three candidates, these cells MUST be 4, 7 and 8 in some order (a 'triple'). This means 4, 7 and 8 cannot appear anywhere else in row 2. Specifically, 4 cannot also appear in col 5, so this now has to be a 6. Hope this helps, apologies if I have misunderstood your confusion.
I've found one amazing puzzle which I want to share with Simon. Can someone please tell me how to share it with him? Channel doesn't contain any email id.
Before the solve began, you mention "hidden-triples". And at the very start of the puzzle using row 1 and col 1, you must have a 478 triple in box 1... could have found it without any pencil markings.
Many thanks for posting this Anthony, glad you all enjoyed it. I should clarify that, while hand-made, it's with software assistance, that software evaluating the grid during the seeding process and identifying the solving steps.
I'd love to see more puzzles made in the same way if the result can be so impressive. Feel free to make more along these lines. I really loved it. There were many cases of cells that could be a given pair and evidence that the cell contained the digit that it couldn't be if you missed something subtle like the 78 pair in column 7, or 478 triple in the top left box to place the 6 in r2c4. Without placing that 6 properly, the top center box was impossible to break into by my normal approach.
@@tadperry1817 I rummaged around and found another nice one (they're a bit rare tbh) and sent to Simon.
That's basically the real meaning of AI: "Assisted Intelligence" 😁
Deano, what is the intended solve path? I used xy-ring to proceed …
The best part of each video is when Simon realizes he's solved it and starts smiling....
I prefer that smile at 3:20 when he realises it's "thinking caps on" - a proper puzzle!
Yasssss I love the part when Simon realizes he solved and starts smiling
27:49 for me, this is the first time I've ever spotted x-wings unassisted, so your channel must be doing wonders for me!
I spotted one of them (the 2s), and almost the 3s... almost...
I think I'm going to save this one until tomorrow. If Simon says a classic sudoku is stunning, I need a fully rested brain to be able to solve it and that's not happening when it's past midnight.
Sending my regards from across the pond in Denver, Colorado! Stumbled across the channel not too long ago and have been so grateful. Thank you both again!
I recently bought all 3 of your apps and I've never enjoyed a sudoku app more, they're absolutely lovely
I love seeing the classic sudoku’s. This was a clever design showcasing X-Wings.
My break-in was _completely_ different! The 4 cells shared by column 1, column 9, row 3 and row 5 contain a 59, 19, 89 and 18, which act as a kind of quadruple x-wing: column 1 can only have a 5 in those cells, column 9 only a 8, row 3 only a 9, and row 5 only a 1.
Samesies! I still needed the other stuff he found, though. Felt like a red herring in retrospect.
Bifurcate here - and GG puzzle :P
Same here, but it brought me nowhere :-)
He could've resolved the last 23 pair in an easier way, but then again, I couldn't have solved this. Great job!
you know it’s a good puzzle when he forgets how to do simple sudoku
When he said “I’m so stupid,” I was sure it was because he spotted the 2 that could go in box 3, but then he went for another x wing.
I almost immediately found an X-wing on 7s in rows 3 and 7 after placing a 7 in r5c6, but it doesn’t advance the solve much until later. I liked your solving path better!
Yes me too :)
...I didn't realize that pattern of 7s was a pair of x-wings, but I did realize that the 7s couldn't go into certain squares that got the same result.
My thought process when i solve sudoku is still too mechanical compared to this guy. I don't think i would have been able to find the x wings without filling the whole grid with all the possibilities. It's incredible how easy it is for him to spot these patterns.
Solved in 56:52, first time solving a puzzle from your channel without having to watch the video when I get stuck. First time using X-wings, Thank you so much for all the content, these videos are awesome.
I love the classic sudokus on this channel! The ones I've tried have been very fluently solved but still somewhat challenging. I got bored of classic sudokus few years ago but finding your channel has really made me enjoy them again!
Managed to solve in 08:35 // Another reminder, I think, that it's a good idea to actively look for X-wings and Swordfishes in these type of 'symmetric' sudokus. Thank you once more for the bonus content! Looking forward to more.
8:58 "Oh, I'm so stupid, so stupid." No, no you are not. That might be the first time I've ever found a puzzle entry faster than you, so allow me my pride!
Honestly I'm amazed I was able to solve that. Something is finally sticking. Total time just under 40 minutes, as usual the hidden triple was a big problem, but I found it!
eric vosselmans he found the the x wings faster. not solved it
@eric vosselmans no he meant at that time of THIS video where simon says he is stupid. He is saying, "simon, don't say you are stupid as that implies you are saying that was an easy move to spot and I am very proud that I spotted this move. Dont take that away from me."
After a few bad starts I watched your solution. Afterwards I tried again and after filling in the obvious marks I worked the perimeter and looked throughout for rows where only 2 of a digit lived. I also found X-wings for 1 & 7. Going at it this way made the puzzle much easier to solve.
More puzzles by Dean Mayer please. this was very beautiful to watch unfold
Wow! What a monster. So many things you have to spot, just to get started on this puzzle. Thanks Simon!
I did the most filled rows and colums first, so started with the edges. That gave me a good start and it was done in 23 min.
Thank you for the extra classic Sudoku. I have loved them all.
Loved this puzzle. Thanks Simon.
I never saw the X Wings. I quickly established that the 5s in row 1 were restricted to box 1. This immediately gave me two symetric tripples in boxes 1 (4-7-8) and 3 (5-6-7). From there, it was relatively clear sailing to the final solution. It was a fun puzzle with, as I now realize, two entirely different manners of reaching a successful solution.
Hey I cracked through this one, but boy it took a lot of effort. This was a really great puzzle and only gradually step by step revealed its secrets.
Fantastic puzzle. Thanks
A puzzle that's filled with mystique,
An interface that's an antique.
This was so fun to play
In an old fashioned way,
An experience that was unique.
Solved in 1h11, I must admit it was REALLY challenging
i think this is favourite puzzle of all time, will keep trying it in different ways and hopefully getting better at it, its pretty deep
loved every bit of it....superb puzzle.
Absolutely beautiful, thank you. At some point, I also spotted a swordfish on 4s which you didn't but, eventually, the result was the same. Again, thank you for the upload. Keep 'em coming, please.
Fabulous handmade puzzle. The best clue at the start was Simon knowing that he was looking for x-wings. That's experience for you!
Wow! Crafty! I really enjoyed this one!
I spotted the 3 x-wings before Simon, so I'm rather proud of that. Once the 478 triple forced a 6 into the middle top square, it kinda just unraveled from there. Great puzzle! I think I'm getting better at these.
thanks for doing these now, its good to have a distraction, a great one at that
+Loved this hard one. I learned a new trick too. Many thanks.
Man! I'm so happy I solved it too. To be honest I tried it after watching this video and used the knowledge of 2/3 x-wing but I couldn't reduction of 478 triplet but after trying to find logic for I found another logic and eventually solved the puzzle.
44:22 solve time for me. I had to watch the video here and there for help but I got it. Without the video I'd have been beyond stuck. I'm still starting to learn all these more advanced patterns.
I think the easier way to spot the first 23 pair is from the geometry. c3r3, c7r3, c7,r7 must go to the three of the four empty spots c1r5, c9r5, c5r1, c5r9. the location of 23 in r5 further constraints to a 23 pair in c5 alone. That means 1 must go to c1/9r5.
Awesome!
I managed to solve this one using SET, although I had to restart a couple times. Wonderful puzzle!
47:15 found the 478 triple right away as well as the 2 and 3 x wings then took forever to see that 78 pair that started the cascade
I had the exact same issue. I gave in and watched the clip, smacked my head, and the puzzle crumbled from there.
At 15:00 Simon identifies the 478 triple. I have a question as to how he could then confirm the 6 in row two when one of the squares he highlights as 478 triple in that row does not contain a 4 ?
Well Simon , all i can say is BOBBINS. In C Am F and G. As you know, with these 4 incredible chords, you can actually play hundreds of songs songs.🎻🎺🥁🎹🎹🎸🎸🎸🎷🎶🎵🎼📯🔔
Beautiful double x-wing! really clever
I spotted the 478 pair, but only after I had painstakingly spotted an X wing with 7s in R3 and 47. So by the time I got there I'd actually found a quadruple instead of a triple!
48 - 47 - 46 - 78
Still cracked the puzzle for me, but wow, took me much longer to get there!!!
This amazing puzzle gave me huge fits. I've gotten a lot better at sudoku puzzles, BUT there must be *something* basic about the proper logic to solving them that I just don't seem to understand yet. I say that because I kept going down logical paths that appeared okay only to keep seeing two same digit trying to go into the same row or column. I'm trying to figure out what I still don't know, but I still haven't figured that out. This puzzle is truly amazing and a learning experience.
I found two X-wings, but couldn't solve it.
Edit: Missed the third X-wing. Then I didn't see the hidden pair (or open complementary open triple and hidden single).
Eventually I solved it by finding a jellyfish.
Got the 478 triple. Got the Xwing on 2s. Failed to spot the X-wing on 3s or the 78 pair in column 7. Superb puzzle though.
18:29 Works for me. Since, at first glance, I didn't even think I'd be able to do it.
3 X-wings (7, 2 and 3), 3 triples, a few pairs... And finally I had it! Great puzzle.
Needed TONS of help with this one, but! I spotted that 478 triple myself in the first box, I just... didn't spot the triple that later caused in row 2. But hey, I spotted a triple, that's progress!
Bifurcated, but not until I found the three x-wings, and I'm ok with that. (Thanks again, stay healthy everyone)
16:22 Only found 1 x-wing, but decided to pencil mark groups of 2 and 3 in a box which actually helped with finding triples. Now to see Simon's solve...
Nice puzzle, some x-wings, some triples (and a key quadrupole), and a swordfish
28:32 for me, proud of myself for spotting a few advanced techniques like the double X-wing and the interesting quadruple in r3c1, r3c9, r5c1, r5c9. I'm interested in what that pattern is called because I haven't seen it before
Edit: Just watched the video, I never found the 478 triple so our solves were way different, interesting to see this great puzzle done a different way
I found the same quadruple as you, definitely the highlight of the puzzle for me. Was disappointed that we didn't get to see Simon react to it
key for me was seeing the top left triple/quad, just luckky to see the 478s interacting
Too hard for me, but thanks for doing extra puzzles. I enjoy watching the solves.
Thank you.
Using a variant of the Phistomefel Ring, one can quickly deduce the "23" pair in Column 5, without using the overlapping X-Wings on 2 and 3.
Nice Riddler look!
WOW that was a toughie!!!
I found something in addition to the X-wings shown in the video: in rows 3 & 5 and columns 1 & 9, you can reduce the four intersections (r3c1, etc) to the same 4 digits: {1, 5, 8, 9}, in ways that restrict those digits; I used that to place a 9 in r2c4 (since there had to be a 9 btw r2c1 and r2c9), and using the additional fact that r2c6 had to be a 2 or 3 (found after the X-wings) and the fact that 5 could not be at r2c5, I restricted the 5 in the top-center box to row 3 and used that to get the four numbers at r3c1, r3c9, r5c1, and r5c9. After that (and with the X-wings), the rest was relatively straightforward.
(Of course, I only got all that AFTER erring and starting over!)
I found the same logic and even resolved it with the same trick with the 5. I was actually unhappy that Simon missed it in his solve, because more than anything else, I wanted to know what that kind of logic is called. It isn't a quadruple despite having four numbers. It behaves somewhere between pairs and X-wings without being either one. What's the official term for this pattern?
@@riluna3695 I found this pattern as well. I wasn't able to resolve it, though I was able to use it to resolve the 9's in box 2 r4c2&3. It was my getting hung up on this pattern that caused me to miss the hidden triple that Simon spotted and caused me to take over an hour to solve the puzzle. There's a guy on youtube here called Sudoku Swami and he claims the pattern supposedly and calls it the "Swami Quad Loop".
th-cam.com/video/VyrTR0x6Xdg/w-d-xo.html
@@ericcrowell9493 Ooh, fascinating! Thank you for sharing that. A "quad loop" definitely makes sense as a name, and if he was the first to "claim" it, then props to him.
Ah man, I used that to solve it too and had never seen it before. I was hunting around for hidden triples and decided to see what would happen if I played with those. I was so excited to see that it worked. I really wanted to see how Simon would react.
That is exactly how I started the puzzle. I was a little disappointed somehow that Simon did a completely different solve. But hey, that was pretty too.
As you recently observed, after 7 in E6 it was obvious that a 7 could not be in any of the 16 corner cells ABHI1289. Because there was no 7 possible in the cells neighboring the central 3-by-3 square.
At time stamp 15:23 , how is it possible to resolve the 6 and eliminate the 4 from row 5? What would happen if the 4 was in column 3 in the top-left 3x3?
The box was a 46 pair and it can’t be a 4 because you’d be left with three 78 squares in row two. Three squares can’t be 7 or 8 so it had to be a 6.
Do you mean column 5? At this point there's three cells in row 2 that can contain only 4, 7, and 8 (columns 2, 3, and 7), so there can't be another 4, 7, or 8 in that row.
I suppose you mean column 5, row 3? It's because if you have a 4 there, it would be 3 squares in row 2 that could only be filled by two digits (7 and 8) - which is not possible.
Two clarify: if it was a 4 in column 3 in the top left 3x3 - what do you put into the 78 square in the top right box?
@@routhy46 Thanks for the cogent explanation. Makes perfect sense. But, as I've claimed in another video, this does not explain how he can claim this is a "478 triple".
@Rod Morningwood I see what you mean. I only have a guess as to why he uses the term “triple” in this case. Three cells in row two can only be the three numbers 478 collectively so it’s considered a triple (three cells, three candidates). I think the term “hidden triple” is used in cases where three numbers are already unique possibilities in three cells, but are buried amongst other candidates. In this puzzle they are not unique within the row because of the 4. But since 478 are the only possible numbers (they aren’t hidden), it’s just a triple. Am I still cogent?
45:42 oh god the amount i thinking i did was wow, there were like 4 x wings. i'm so proud of myself
Technically 5, because there were TWO x-wings on 7.
Very hard .. found triple in box 1 straight away, but then didn't know what to do with it .. needed assists to complete .. very nice puzzle ..
I tried before watching the video. It took nearly an hour. I watched the video until 3.55 and was happy I didnt miss anything simple. Hoping to see if the xw7 is explained, as I really felt like I winged it.
Amazing, just went to completely different ones. Learning all the time
There is an interesting quadruple in r3 c1&9 and r5 c1&9 as well. It didn't break open the puzzle for me but it being there right at the start did help me later on.
At 7:05 when you identified the first X wing on the 2's you missed placing a 2 in the last column on the 2nd row, I was shouting at you, 'it's there!!', but you didn't hear me. It's something I do a lot when the grid starts getting busy. I have another Soduku game that lets you highlight all occurrences of a number which I find useful but doesn't support proper Sneider notation so I've stopped using it. Does anyone else think being able to highlight all occurrences of any number is a useful feature to add to your web app? Which I love by the way. Thank you CTC.
At that point, it seems to me that the 2 in box 3 could be in either r1c8 or r2c9.
26:24. The 2 x-wings were cool one those 6s landed into place.
C1R7 + C9R7 is a 239 only and rules out the 9. Then with the 8 in C4R8 we get a 23 pair in C5R9 + C6R8 which makes a 46 pair in C4R7 + C6R7. Slightly different approach.
21.22
ty for the puzzle
World is in dire peiil! We need geniusses to save us all!! Crackling his Knuckles...right...but I need to solve this Sudoku first....
Stay save you all!
Near the end in lower left block, I didn't follow why 9 couldn't also be in the middle cell when you said it had to be in the middle column, top?? Good instructive video. Thanks. (Beginner).
Simon's looking at what numbers still need to be placed in row 7. It still needs a 2, 3 and a 9. In the cell you are looking at, where he puts a 9, he can rule out 3 because there is already one in the column, and rule out 2 because of the pencil marked 2's both in the box and in the column.
Hope this helps.
I'm somewhat new to sudoku. How in the world you spot that 7,8 restriction is beyond me
How to mark the numbers in the box(above)
That was hard.
42:12 for me. Took me a while.
I don't understand how he did that in 15:25 can someone explain please?
If you have 3 squares that all must contain the same 3 numbers then they form a triple. The 4 MUST go in one of those three for it to work out so you can eliminate it from r2c5. אלה מורה
Question: I noticed a pattern I thought was interesting, The four cells in Rows 3 & 5, Columns 1 & 9, were limited to 1589 in pairs. This pattern restricted 5's in C1, 8's in C9, 9's R3, and 1's in R5. These restrictions got me to wondering. Does this pattern have a name?
Yes I also came across this and it was stunning! Haven't seen or heard of it before. Too bad Simon solved one of the corners early with his 78 trick. I was really hoping to see his reaction and explanation when he found it. Anyhow, if it doesn't have a name, I suggest quadruple X-wing.
it is called XY-chain. look here www.sudokuwiki.org/XY_Chains. I also found this chain though that did not help much. Still a very cute arrangement!
Started the puzzle by finding the X wing on 7's, gave up shortly after.
Watching Simon's solve: "Ah there is an X wing....on 2's!" and shortly after " Oh there is another X wing, on 3's!"
Colour me surprised, nice setting with this puzzle.
There's also an x wing on 1s as well. ;p
Got it in a little over 8 minutes.
A time of 40:29 for me, only because I'm still ABSOLUTELY RUBBISH at spotting triples. I got the X-wing on 2's and 3's very easily, the swordfish on 4's was easy to spot, but the 459-triple in column 7 took me far too long to spot.
Anyone else notice the x-wing on 7s? It made me wonder if there was a deeper tactic I was missing, since that was 3 x-wings.
Well, whatever it was, makes me feel good that Simon must have missed it too if it did exist :D
I noticed both of the x wings on 7, but they didn't help until later on in the puzzle. There was also an early x wing on 1s.
I managed to find exactly one number before starting to watch the video.
The 7 in row 5. Me too.
I have the 7 and contemplating if I should watch the video. I don't want to give in. lol. So i am reading the comments hoping for some guidance.
@@kimberlypreston6204 I do that, too. It feels like medium cheating ...
I solved this in maybe 40+ minutes with first some very basic moves and then had huge troubles and colored paths for candidates. I didn't even find any triples.
I did find the triple in box 1. I did not spot the x-wings, nor did i get the 78 pair out of it after watching the video. This one's a bit too hard for me! Nice puzzle though.
I got that 7.
Hahahaha! Yep, same here.
Hoping someone can clear my confusion here. At 9:58 it is decided that because of the 4,6 pair that 8 must be in 2nd cell in the 5th box. He then places that 8. However, I thought earlier it was said that the centre cell of the 8th box (the cell 4 positions directly below where the 8 is placed, 1 above the pink box) could be "loads of numbers" at 8:14. Could someone explain how it was determined that this cell was not an 8? There seems to be no 8s anywhere else to confirm this "Couldn't" be an 8? Thanks
It could have been an 8. But the 7 could only go into 2 cells in column 5. Rows 89.
The x wings on 23 in column 5 removed the possibility of R9 C5 being a 7. Forcing the 7 into R8 C5.
@@glennmelven3414 Thanks for your response. I see your logic, but I think I got confused because he solved that 7 AFTER he had placed the 8. He places the 8 when it could be either and his decision is only confirmed once the x wing confirms the 7 after. Or are you saying that he probably knew it was a 7, and just didn't explain it until after? Sorry!
@@sshblack At the time he got the 23 xwing and the 468 triple, both the 7 and 8 were available.
@@glennmelven3414 Thank you very much for your patience!
At the time Simon places the 8 in the centre box it is the only candidate still available for that particular cell. (1,5,6,7, 9 are ruled out by other placed digits; 2,3 by the two x-wings that lock 2,3 pair into the top and bottom cells; 4,6 by these being the only candidates for two other cells in the column).
I hope this helps.
At 10:18 can anyone help me explain how could 8 go there but not at row 8 or 9?
Once the 23 pair is locked into the overlapping X wings, 3's are eliminated from the other cells in column 5. That turns the cells with 346 into a 46 pair, thereby eliminating the 4 from the 48 pair in r4c5, leaving just the 8.
1:05:59 an hour.
Goood 23 pairs 👏👏
I think there is an easier way to this puzzle... apart from the 2 and 3 xwing, there is a 7 xwing on row 3 and 7 which gives a 236 triple in row 9. With that, the rest of the puzzle essentially resolves
Found x-wing on 7, missed the 2, found the 3. Found the triple right away. But I needed the 78 pair to finish it. Yikes!
I found 4 x-wings, many hidden pairs and triplets. It took a very long time but I am quite proud of myselt.
15:10 - You say it's a 478 triple, but R2C3 can't be an 8 so how is it a triple? (sorry for newbie question)
478 triple in upper left 3x3 box as a result of 478 in column 1 and row 1, could have made things simpler . A 23 pair in 1st row and column 5 , and 23 pair in the last row and column 5..
I solved it. Took a bit longer than 20 mins mind. I found the X wings but I missed that 4,7,8 triple in the top left box.
15:20 I really wish you would explain how you arrive at 478 triple the way you always explain x-wings
Your name has me dying my friend hahahah Mr. Morningwood
Simon has worked out that there are three cells in row 2 that are restricted to being 4, 7 or 8. Since there are three cells and three candidates, these cells MUST be 4, 7 and 8 in some order (a 'triple'). This means 4, 7 and 8 cannot appear anywhere else in row 2. Specifically, 4 cannot also appear in col 5, so this now has to be a 6.
Hope this helps, apologies if I have misunderstood your confusion.
I've found one amazing puzzle which I want to share with Simon. Can someone please tell me how to share it with him? Channel doesn't contain any email id.
Anyone else find the two X-wings on 7? Actually really want Simon to redo and look for X-wings instead of pushing so hard on only the 2 and 3 xwings
Yes, but it didn't lead me anywhere. Spent far too long on the sevens.
yeah, those were some massive red herrings
They help later in the puzzle, but only offer a little early on. I actually got 12 pairs in the top boxes off those x-wings too.
Крутой мужик
Before the solve began, you mention "hidden-triples". And at the very start of the puzzle using row 1 and col 1, you must have a 478 triple in box 1... could have found it without any pencil markings.