2:19:02 for me. I had a hard day at work, which tired me physically, and then I went and did this puzzle, which tired me mentally. I fell asleep for half and hour and spent another half hour taking a bath.
A simple way to get the 4s: First, from where Mark stalled, the 8s around the grid force an 8 into r2c7. After that, you can do Snyder notation for the 4s in boxes 1, 3, and 4, and you'll notice they form the corners of two off-set rectangles. Whenever you see that pattern, you know that the last box, it creates a target in the box where the last corner would be, which eliminates the 4 from r6c7 and r5c8. That actually doesn't solve it in this case, but it drew my attention to the 4s in box 6, and if you treat the 4s in box 5 as a pass-through you can see that they effectively make row 4 into honorary members of row 5, so that placing a 4 in r4c8 has the same effect as r5c8 which would complete the rectangle and break the puzzle. that means the 4 in box 6 is in column 7, which untangles the rest of them.
Solid puzzle. Just barely squeaked in under 10 minutes at 9:50. Struggled a bit in the center before I found a skyscraper that broke the puzzle, something I haven't seen on this channel in a very long time! Really enjoying these short classics at the end of the day, gives me a nice bit of a brain break before dinner and bed. :) EDIT: Spoilers follow. Where I found the skyscraper was on 4's in rows 2 and 6. You missed that r2c7 was the only candidate left for 8, which forces 4 into r2c38. In Row 6, you already had 4's limited to r6c37. This forms a skyscraper and eliminates r1c7 and r4c8, and then forces the majority of the 4s in exactly the same way as the chain you found.
After a lot of staring at the sticky bit, I found a double skycraper of 4&5's in row 2 which eliminated them from r4c8 making it a 7. Everything fell into place from there. When I watched the video the wizardry with the 4's was amazing. This channel is teaching me so much and is my favourite time waster
As a beginner I got it in 47:58 minutes, and I was stuck, but your technique of imagining a chain of 4s and seeing whether the others would fit helped me break my own deadlock. Thank you!
14:25 for me! I usually don't rely on the empty rectangle because I don't really like how there's no set pattern for the rule, compared with an X-wing, a swordfish, a Y-wing, an XYZ-wing, a WXYZ-wing, and the like. But here I was able to do it, and I spotted the thing with the 4's at the end too so that's nice.
Nice little puzzle, took me 56 minutes to complete. I found the 9s immediately as well as the first 5 afterwards, but then I got distracted by filling in all the theoreticals for each box. Once I had done that I was a little stumped until I noticed a single cell within a 3 x 3 box that had the only possibility for a single number in the whole region, that then had me blitzing to the finish.
At 5:00, there is a bit of a sticking point. Mark solves it with a short chain, because that technique suits him. I used that as well, because it's pretty natural for me. It's apparently called "simple colouring" or "pincers", and it's absolutely forced, and fully legitimate. Mark isn't particularly interested in the label, although naming a thing does help if you want to talk about it. Several commenters apparently used a skyscraper, which i don't see. However, Simon would have immediately found and used an "empty rectangle" in box 6, as follows. If r4c7 or r4c8 is a 4, then r6c3 must be a 4. If c7r5 or c7r6 is a 4, then r6c3 must be a 4 (via box 3, then 1). That's all, folks.
I used a move I learned as a Skyscraper to eliminate the 4 and 5 from the column 8 leaving the empty 7. First off in R2 the 5's could only go into C1 and C8, and in R6 in C1 and C7, so whatever cell seen by both R2C8 and R6C7, like R4C8 and R3C7 could not be 5. There was a similar solution for 4's in R4C8 leaving only a possible 7 there.
The most interesting and useful for me was the conclusion that there could only be one 1,7 pair in top left row 2. You can't have three matching pairs in a row. I'd seen the situation before but the penny didn't drop until now. Definitely a doh! moment, and so another tiny step forward. Thanks!
Thanks, this was very helpful to watch. Just as you got silent for a long time, I saw that the 8 eights already in place locked in the eight in row two, column 7, which you didn't see until a good while later. As you say, there are several paths to a solution. Thanks!
My logic when reaching the bottle neck was a little bit different, The 17 in c2 restricts them to 3 spots in box 1. 17 are the only possibilities for r2c9 which meant that the 1/7 in box 1 could not both be in the second row, this meant that r1c1 could now only be a 1/7, which then formed a 1/7 pair with r1c6, which gave me a 24 pair in r1. this allowed me to get a few digits including the 3 in box 4. Then I used simple chaining to see that if r6c7 was a 4 there would be no possible position for a 4 in box 4, there was only 1 other location for the 4 in r6 which then broke the puzzle open overall it was a fun solve, took my 19 minutes Edits: hadnt watched far enough turns out he explains the 1/7 pair in the video
It took me 36 minutes. I started highlighting candidates, and when I came to the 4s I was able to eliminate c2r5 with a five-step x-chain, something similar to what Mark did.
I took 8:40 and was super straightforward. I found I misplaced a 5 halfway trough the solve and prayed for it not being a big mistake so I probably got lucky lol
26:46 happy with the result, got very hard stuck at some point, so i tried to bifurcate in my head the r1c7 as a 4 and noticed it couldn't be, so puzzle was cracked after that(glad to see he did basically the same logic, at around 6 minutes on this video)
@@gizmo3728 When a number is locked into a L shape in a box then it must either be on the vertical or horizontal part of that L. If you can then get a chain of inferences which rules out a particular cell in both cases, then you know that cell can never contain the number. In essence, the same approach as the video but starting from the opposite end of the chain. In this case, 4 was either in row 4 or column 7 in block 6. If you chase the pairs of 4s round you find that r5c2 cannot be a 4 in either case.
29:19. Found a sort of extended empty rectangle on 4s - after checking several other digits first. Still don't immediately spot these patterns but at least I'm spotting them eventually now.
When I got to the sticky part with the 4s, I did a skyscraper on them, as 4 was restricted to two cells in Columns Three and Eight. This showed me that R6,C7 was a false candidate that, in turn, indicated that 4 could only have one possible location in Row Six. I had most of the puzzle done by that point, so I didn't need to do the trick with the 1s and 7s in Box One. A big thanks to Yosh over on the Discord server for teaching me about skyscrapers (and turbot fish)!
27:14! Really proud of myself, it was actually quite hard! I also had to use a chain to find the solution, but I don't remember if it was the 4 or something else.
With all respect for the both of you, I watch many episodes, I was hoping for some more lessons in this one, as the tile suggests. When I start a new puzzle I can add digits and/or pencil-marks in a few seconds and then suddenly it all stops. I don't see what else I can do. Is it possible to explain the techniques you are doing in detail? Maybe not finishing a puzzle completely but by using examples explaining how you add digits. It happens often that I finish a puzzle to find out I made errors and I suspect it is done when using pairs. I always find it difficult to see when cells are pairs and when not. Thanks.
Took me 26:18 without understanding what is a skyscraper. Eventually I just chain the numbers like Simon and found the solution :D I remembered someone name it a slot machine in this channel before.
Not an expert by any means, but sailed through this one 15:19 without getting stuck (just using a trackpad that made me slow! ... looking at all the comments about '4s' and swordfish... I don't think I had any of those issues.....going to watch the video now to see if I just got lucky...
I decided to feed this into Andrew Stuart's sudoku solver and turns out that the technique Mark used at the end is indeed called simple colouring! It was the only technique it used that wasn't a basic technique.
This was a neat puzzle (Went nicely all around the grid) Took me 26 mins (But it was 2 o'clock in the morning after all) A nice solve 😆☕🍺 PS: for me, this fought to the bitter end hanging onto different pairs all over the grid eliminating one by one. (Then 2 by 2 ) I didn't need to do any "chaining" in other words. (That's Bifurcation in a way in my book) (At least starting out) [[ picking between those 4s in case I wasn't clear lol ]] Good job seeing it though Nice puzzle Cheers again ☕🍺 PPS: Mark's quick, I'll give 'im that. Most definitely lol
You've missed the 8. And that made me think that my approach might be not that bad. Although I'm not an expert in any means :D. What I'm doing, is circling through the numbers from 1 to 9 and then again from the beginning. This avoids that I forget something because I'm randomly focusing only on patterns. Is this something unusual? I don't know … I'm really not an expert.
15:54 for me. It seemed to proceed completely logically. I went through it in a completely different order, and didn't have to eliminate the 4s like that.
It's strange (not really) how doing the solve in a different order can make things easier or harder - I found the 4 in r1c2 earlier, so that chain was not needed. 17 minutes - my fastest ever on this channel.
It's the basic sudoku. Manage to solve with hardest technique being line/box reduction. Didn't watch the video, but see that in comments ppl refer to some "trick with 4s". Any time code?
jalsing Easier with an empty rectangle in cell 6 , forcing the 4’s into either R6 (which interacts with cell 5...and eliminating a 4 from R1C7) or C7 which does the same in eliminating a 4 from R1C7. Puts the 4 in R1C2, and easy from there.
How do you decide where to start? I tend to look if all the 1's are there than 2 etc, or in this case I would just look at the upper left box first an than I notice the 6 is in 2 positions in the upper 3 rows so it's easy to decide where the third has to go. I don't really have 1 way of starting a sudoku. I just start. What do you look at first?
I found the same 4 in a roundabout way with a triple in column 3 that resonated with the 1-7s that I had sorted earlier because I got the 8 in box 3 sooner. Definitely agree that this is a computer generated puzzle, the trick was too ugly to have been human crafted.
great to watch these done so quickly. I completely didn't understand the logic of the 17 pairings in the top left box. Why did one have to be a 17 pair??
In column 2 you already have a 1 and a 7, so box F3C2 cannot be 1 or 7. In box R2C9 there was either a 1 or a 7. So if that were to be a 1, then the 1 in box 1 could only go in R1C1. If R2C9 would be a 7, then the 7 in box 1 could only go in R1C1. Conclusion: R1C1 will always be a 1-7 pair and it will be exactly the same value like R2C9.
Didn't like this much. I had the naked 8 in box 3, (how did he miss it?). I couldn't see the trick with the 4s, had to watch, and with that clue the whole thing fell apart instantly. I've never heard of "pincers" - maybe we need a tutorial on spotting those?
I can try to write how I look at it. Every 3x3 box needs both a 1 and a 7. There are four empty squares in the top-right box, but both 1 and 7 is ruled out from one of them. Two squares "see" the 1:7 pair on the right, which means that those two squares can only contain either a 1 or a 7 - they can't contain both. After all that, there's still either a 1 or a 7 left to place in the box and it has to go into to the top right square.
Hamza Hussain he uses the 1&7 already in column 2 to eliminate both from r3c2. He then notes r2c9 must be a 1 or a 7, so whichever one it is can only go in r1c1. If r1c1 were a 2 for example, 1 and 7 both wouldn’t fit in the top left 3x3 block
This was an interesting solve but I don’t see how the ‘trick’ with the 4’s is anything but bifurcation or in other words, guessing which one of 2 cells it might be in and then moving forward through the solve until you reach a point where it’s either broken or solved. You were able to do it in your head because it was only a few moves forward before the break but surely this is bifurcation due to it being an app created puzzle with no purely logical solution?
8:10 here. found some naked singles that sped it along. This was the first puzzle I tried real hard not to pencil mark more than two cells in a box, and it seemed to make a lot of difference. I just worked my way up from 1-9 around the grid and it fell out quickly.
Man, that move with 4s was crazy
dude it's literally sudoku and i've never felt more mentally outclassed in my entire existence by that 4 thing
How he find that naked 4?
Jess Cainag You mean are 2:35?
1,3,5,7,8, 9in the box, 2 and 6 in the column
That "magic 4" cause me to hit a wall for almost an hour.
It took me 50 minutes and most of that was looking for that thing with the 4s that you spotted in 2 seconds. Very humbling.
2:19:02 for me. I had a hard day at work, which tired me physically, and then I went and did this puzzle, which tired me mentally. I fell asleep for half and hour and spent another half hour taking a bath.
That's about how I usually solve these, too. But occasionally I get to focus on it.
A simple way to get the 4s: First, from where Mark stalled, the 8s around the grid force an 8 into r2c7. After that, you can do Snyder notation for the 4s in boxes 1, 3, and 4, and you'll notice they form the corners of two off-set rectangles. Whenever you see that pattern, you know that the last box, it creates a target in the box where the last corner would be, which eliminates the 4 from r6c7 and r5c8. That actually doesn't solve it in this case, but it drew my attention to the 4s in box 6, and if you treat the 4s in box 5 as a pass-through you can see that they effectively make row 4 into honorary members of row 5, so that placing a 4 in r4c8 has the same effect as r5c8 which would complete the rectangle and break the puzzle. that means the 4 in box 6 is in column 7, which untangles the rest of them.
Solid puzzle. Just barely squeaked in under 10 minutes at 9:50. Struggled a bit in the center before I found a skyscraper that broke the puzzle, something I haven't seen on this channel in a very long time! Really enjoying these short classics at the end of the day, gives me a nice bit of a brain break before dinner and bed. :)
EDIT: Spoilers follow. Where I found the skyscraper was on 4's in rows 2 and 6. You missed that r2c7 was the only candidate left for 8, which forces 4 into r2c38. In Row 6, you already had 4's limited to r6c37. This forms a skyscraper and eliminates r1c7 and r4c8, and then forces the majority of the 4s in exactly the same way as the chain you found.
After a lot of staring at the sticky bit, I found a double skycraper of 4&5's in row 2 which eliminated them from r4c8 making it a 7. Everything fell into place from there. When I watched the video the wizardry with the 4's was amazing. This channel is teaching me so much and is my favourite time waster
As a beginner I got it in 47:58 minutes, and I was stuck, but your technique of imagining a chain of 4s and seeing whether the others would fit helped me break my own deadlock. Thank you!
I stared at that sections for 20 min. before I just gave up and watched the video, that 4 move was ridiculous
14:25 for me! I usually don't rely on the empty rectangle because I don't really like how there's no set pattern for the rule, compared with an X-wing, a swordfish, a Y-wing, an XYZ-wing, a WXYZ-wing, and the like. But here I was able to do it, and I spotted the thing with the 4's at the end too so that's nice.
15:32 a skyscraper on the 4s in C3 and C8 cracked it for me but took a while to find it
Nice little puzzle, took me 56 minutes to complete. I found the 9s immediately as well as the first 5 afterwards, but then I got distracted by filling in all the theoreticals for each box. Once I had done that I was a little stumped until I noticed a single cell within a 3 x 3 box that had the only possibility for a single number in the whole region, that then had me blitzing to the finish.
At 5:00, there is a bit of a sticking point. Mark solves it with a short chain, because that technique suits him. I used that as well, because it's pretty natural for me. It's apparently called "simple colouring" or "pincers", and it's absolutely forced, and fully legitimate. Mark isn't particularly interested in the label, although naming a thing does help if you want to talk about it. Several commenters apparently used a skyscraper, which i don't see.
However, Simon would have immediately found and used an "empty rectangle" in box 6, as follows.
If r4c7 or r4c8 is a 4, then r6c3 must be a 4.
If c7r5 or c7r6 is a 4, then r6c3 must be a 4 (via box 3, then 1).
That's all, folks.
I used a move I learned as a Skyscraper to eliminate the 4 and 5 from the column 8 leaving the empty 7.
First off in R2 the 5's could only go into C1 and C8, and in R6 in C1 and C7, so whatever cell seen by both R2C8 and R6C7, like R4C8 and R3C7 could not be 5. There was a similar solution for 4's in R4C8 leaving only a possible 7 there.
The most interesting and useful for me was the conclusion that there could only be one 1,7 pair in top left row 2. You can't have three matching pairs in a row. I'd seen the situation before but the penny didn't drop until now. Definitely a doh! moment, and so another tiny step forward. Thanks!
Thanks, this was very helpful to watch. Just as you got silent for a long time, I saw that the 8 eights already in place locked in the eight in row two, column 7, which you didn't see until a good while later. As you say, there are several paths to a solution. Thanks!
My logic when reaching the bottle neck was a little bit different, The 17 in c2 restricts them to 3 spots in box 1. 17 are the only possibilities for r2c9 which meant that the 1/7 in box 1 could not both be in the second row, this meant that r1c1 could now only be a 1/7, which then formed a 1/7 pair with r1c6, which gave me a 24 pair in r1. this allowed me to get a few digits including the 3 in box 4.
Then I used simple chaining to see that if r6c7 was a 4 there would be no possible position for a 4 in box 4, there was only 1 other location for the 4 in r6 which then broke the puzzle open
overall it was a fun solve, took my 19 minutes
Edits: hadnt watched far enough turns out he explains the 1/7 pair in the video
It took me 36 minutes. I started highlighting candidates, and when I came to the 4s I was able to eliminate c2r5 with a five-step x-chain, something similar to what Mark did.
Your puzzles give me a headache!!! Keep up the good work!! I'.m addicted in Pennsylvania,, USA
I took 8:40 and was super straightforward. I found I misplaced a 5 halfway trough the solve and prayed for it not being a big mistake so I probably got lucky lol
26:46 happy with the result, got very hard stuck at some point, so i tried to bifurcate in my head the r1c7 as a 4 and noticed it couldn't be, so puzzle was cracked after that(glad to see he did basically the same logic, at around 6 minutes on this video)
19:41 for me. Really felt proud of this one even though it took me a while to spot the swordfish. Curious to see if that's how you did it too!
The 4s could also be found using an empty rectangle trick in block 6.
What is that
@@gizmo3728 When a number is locked into a L shape in a box then it must either be on the vertical or horizontal part of that L. If you can then get a chain of inferences which rules out a particular cell in both cases, then you know that cell can never contain the number. In essence, the same approach as the video but starting from the opposite end of the chain.
In this case, 4 was either in row 4 or column 7 in block 6. If you chase the pairs of 4s round you find that r5c2 cannot be a 4 in either case.
Jeremy Butler
Thanks! That is a better way to find that chain.
that thing with the 4's was actually insane
29:19. Found a sort of extended empty rectangle on 4s - after checking several other digits first. Still don't immediately spot these patterns but at least I'm spotting them eventually now.
When I got to the sticky part with the 4s, I did a skyscraper on them, as 4 was restricted to two cells in Columns Three and Eight. This showed me that R6,C7 was a false candidate that, in turn, indicated that 4 could only have one possible location in Row Six. I had most of the puzzle done by that point, so I didn't need to do the trick with the 1s and 7s in Box One. A big thanks to Yosh over on the Discord server for teaching me about skyscrapers (and turbot fish)!
The naked 4 at 2:35? I don't get it. The 4 wasn't restricted to that cell by either the block or the column. There seemed to be other choices.
27:14! Really proud of myself, it was actually quite hard! I also had to use a chain to find the solution, but I don't remember if it was the 4 or something else.
With all respect for the both of you, I watch many episodes, I was hoping for some more lessons in this one, as the tile suggests. When I start a new puzzle I can add digits and/or pencil-marks in a few seconds and then suddenly it all stops. I don't see what else I can do. Is it possible to explain the techniques you are doing in detail? Maybe not finishing a puzzle completely but by using examples explaining how you add digits. It happens often that I finish a puzzle to find out I made errors and I suspect it is done when using pairs. I always find it difficult to see when cells are pairs and when not. Thanks.
that trick with the 4s was great
i would not have spotted it, but realise now that the interaction with the 45 pais made it an obvious one to try
skyscrapers ftw. never ignore the x-wing's lop-sided cousin
Wow. That is SUCH a difficult solve!
Really enjoy these videos my solving skills improve a little everytime . the phone app is addictive and maybe the best out there.
Took me 26:18 without understanding what is a skyscraper. Eventually I just chain the numbers like Simon and found the solution :D
I remembered someone name it a slot machine in this channel before.
For me it was an empty rectangle on 5s in box 4 which chained to eliminate the 4 in R4C5
16:47. The skyscraper of 4 cracked me up.
How do you get so fast at identifying naked singles? Practice, or is there some thought pattern to keep in mind?
Same question hope he replied
Just to clarify, we're still talking about Sudoku, right? I'm okay with either outcome.
@@WeretigerX well played, good sir
I DONT GET NAKED SINGLES. HOW TO SPOT THEM?
i found an good explanation here: www.sudoku-solutions.com/index.php?page=solvingNakedSubsets
Finally!! Did it on the 4th try. This was very tricky for me.
The only trick needed was the one that eliminated the 4.
But how to see that trick? It's neat, but it didn't the explanation didn't help me.
There were other things to do, for example the 8 in the top-right box
@@vittorio1159 I did that first, but I still needed the trick with the 4 to finish it off.
I solved without this trick
@@sunil-pt7ez Did you use an empty rectangle/skyscraper?
Not an expert by any means, but sailed through this one 15:19 without getting stuck (just using a trackpad that made me slow! ... looking at all the comments about '4s' and swordfish... I don't think I had any of those issues.....going to watch the video now to see if I just got lucky...
..I didn't do the tricks with the 4s... or the 17 pairs..... can't remember my sequence but it wasn't anything special!
I decided to feed this into Andrew Stuart's sudoku solver and turns out that the technique Mark used at the end is indeed called simple colouring! It was the only technique it used that wasn't a basic technique.
This was a neat puzzle
(Went nicely all around the grid)
Took me 26 mins
(But it was 2 o'clock in the morning after all)
A nice solve 😆☕🍺
PS: for me, this fought to the bitter end hanging onto different pairs all over the grid eliminating one by one.
(Then 2 by 2 )
I didn't need to do any "chaining" in other words.
(That's Bifurcation in a way in my book)
(At least starting out)
[[ picking between those 4s in case I wasn't clear lol ]]
Good job seeing it though
Nice puzzle
Cheers again ☕🍺
PPS:
Mark's quick,
I'll give 'im that.
Most definitely lol
A'm doin' the puzzle again.
This was fun, Mark lol 😆☕🍺(here, have some beers and cheers)
28:10 was flying to start and then I got stuck. Considering how short the video is I am sure I missed something. Now to see what.
16:08, but I had to bifurcate twice as I didn't notice the full trick with the 4s (though I did notice the interesting groupings). Still a fun puzzle!
You've missed the 8. And that made me think that my approach might be not that bad. Although I'm not an expert in any means :D. What I'm doing, is circling through the numbers from 1 to 9 and then again from the beginning. This avoids that I forget something because I'm randomly focusing only on patterns. Is this something unusual? I don't know … I'm really not an expert.
I needed help with that sticking point, but other than that, not too bad of a puzzle even for an amateur like me
15:54 for me. It seemed to proceed completely logically. I went through it in a completely different order, and didn't have to eliminate the 4s like that.
Same here!
22:20, took me a bit to see the trick with the 4's, but once I got that the rest of the puzzle fell apart.
33:07 for me. Without listening to logic, nor bifurcating!
It's strange (not really) how doing the solve in a different order can make things easier or harder - I found the 4 in r1c2 earlier, so that chain was not needed. 17 minutes - my fastest ever on this channel.
It's the basic sudoku. Manage to solve with hardest technique being line/box reduction. Didn't watch the video, but see that in comments ppl refer to some "trick with 4s". Any time code?
4s solved it for me there was just some spots where it couldnt go
I'm still a beginner and I finished it in 48:13
I don't see how you got the naked 8 at 1:59. An 8 could have gone in the 1st cell of either the column or row. Help!
18:08 the 4's really broke things open
that 4's chain is more easily seen by using skyscraper technique (on 4s) in rows 1 and 6
jalsing
Easier with an empty rectangle in cell 6 , forcing the 4’s into either R6 (which interacts with cell 5...and eliminating a 4 from R1C7) or C7 which does the same in eliminating a 4 from R1C7. Puts the 4 in R1C2, and easy from there.
@2:28 why must it be a 7 and the next a 3?
14:51 good puzle
11:28 Maybe the first time I found an empty rectangle on my own. (At least, that's what *I* needed to finish.)
A little over 7mins for this one... pretty straight forward it seemed.
How do you decide where to start? I tend to look if all the 1's are there than 2 etc, or in this case I would just look at the upper left box first an than I notice the 6 is in 2 positions in the upper 3 rows so it's easy to decide where the third has to go.
I don't really have 1 way of starting a sudoku. I just start. What do you look at first?
Me... just a quick scan to see if there are lots of a particular number... or if there are lots in a particular box, column or row
This is crazy I have never used any technique but simple process of elimination maybe that’s why it takes me 20-30 mins to solve these🤷🏼♂️
Took me 40 minutes, but didn't figure out anything. Just got lucky by following a 7 all the way to the end.
20:04 while eating. Was it easy or am I getting better?
can someone explain how he found that "naked single 4" at 2:35? the square left of it could've also been a 4?
I'd like to know also, I am seeing the same thing as you.
the 2 empty squares above that one can only be 1 and 7 making that lone one 4
@@03189078 wow, yeah, i didn't notice that, tnx!
@@03189078 Thanks
1:59 How did you determine that C6 R6 had to be 8? What ruled out C6 R1? I don't follow that leap.
I'm assuming he knew C6 R6 had to be a 1, 7 or 8, but it couldn't be a 1 nor 7 because of the 1 and 7 already on R6
@@marcosdassen3305 Oh! I see that now.
@@marcosdassen3305 Thank you! I was curious about this as well!
30:23 but I was doing other things at the same time (listening to videos about other subjects)
13:15 My eyes were drawn to the 4s, but I can't say why they were, probably lucky more than anything.
15 minutes. It doesn't require any advance technique. Just to pay atention haha
Yes, as he showed. Indeed it does not. And he didn't use one.
I found the same 4 in a roundabout way with a triple in column 3 that resonated with the 1-7s that I had sorted earlier because I got the 8 in box 3 sooner. Definitely agree that this is a computer generated puzzle, the trick was too ugly to have been human crafted.
Found a skyscraper with the 4s
great to watch these done so quickly. I completely didn't understand the logic of the 17 pairings in the top left box. Why did one have to be a 17 pair??
r3c2 could not be a 1 or 7, r2c1 + r2c3 could not BOTH be 17 because r2c9, so r1c1 had to be either 1 or 7
In column 2 you already have a 1 and a 7, so box F3C2 cannot be 1 or 7. In box R2C9 there was either a 1 or a 7. So if that were to be a 1, then the 1 in box 1 could only go in R1C1. If R2C9 would be a 7, then the 7 in box 1 could only go in R1C1. Conclusion: R1C1 will always be a 1-7 pair and it will be exactly the same value like R2C9.
2 30 in you could have goten the 8 on the top right box but it was one of the last things you did ...
I got an hour in before I realized I broke it and didn't have it in me to go back and find the problem ._.
I'm confused. I normally struggle to solve all but fairly simple puzzles, but this one I didn't seem to find any sticking points.
Didn't like this much. I had the naked 8 in box 3, (how did he miss it?). I couldn't see the trick with the 4s, had to watch, and with that clue the whole thing fell apart instantly. I've never heard of "pincers" - maybe we need a tutorial on spotting those?
14.25
ty for the puzzle
I did not understand the logic of the 1:7 pair (ca 7:20min), it seemed to imply that every pair must have a matched pair. Can someone explain this?
I can try to write how I look at it. Every 3x3 box needs both a 1 and a 7. There are four empty squares in the top-right box, but both 1 and 7 is ruled out from one of them. Two squares "see" the 1:7 pair on the right, which means that those two squares can only contain either a 1 or a 7 - they can't contain both. After all that, there's still either a 1 or a 7 left to place in the box and it has to go into to the top right square.
@@stenis999 Thank you! I completely missed the 1:7 pairs in the central box - so many times I miss the really obvious.
2:34: Why had it to be a naked 4 there?
6:38 no problemo
There's never a single problemo with you
that great buddy
This one was totally straightforward
So I'd have to agree with you there.
You do say that a lot though lol
Cheers 😆☕🍺
it took me about 45 min :) i am quite proud of that, though i did it differently than you
12:35 not bad at all for me
Tapping on the screen and saying 7 doesn't seem to help.
20:29 but heck, I';m not ashamed.
21:02
9:56 just under 10 mins.. yes
At 2:00 , why does it have to be an 8?
Woot, 18.5 minutes because of a finned swordfish on fives. (For those interested: r145, c245 with fin at r3c2)
18:30
i can't follow the logic why the upper left cell can't be a 1-7 cell.. to me it can be.. haven't watched til the end yet. I wanna solve it myself
I dont understand the 1,7 logic starting from 6:50..Why 17 pair has shifted to that top box.
Hamza Hussain he uses the 1&7 already in column 2 to eliminate both from r3c2. He then notes r2c9 must be a 1 or a 7, so whichever one it is can only go in r1c1.
If r1c1 were a 2 for example, 1 and 7 both wouldn’t fit in the top left 3x3 block
This was an interesting solve but I don’t see how the ‘trick’ with the 4’s is anything but bifurcation or in other words, guessing which one of 2 cells it might be in and then moving forward through the solve until you reach a point where it’s either broken or solved. You were able to do it in your head because it was only a few moves forward before the break but surely this is bifurcation due to it being an app created puzzle with no purely logical solution?
There exists forced logic with an empty rectangle in box 6 at that point. Short chains, which Mark prefers, are not considered bifurcation.
5:00 chain timestamp
45:13
I solved it with a skyscraper on 4s.
Took me 39:28
Why is he mad that it's weird this time instead of happy that it's weird?
8:01 for me.
8:10 here. found some naked singles that sped it along. This was the first puzzle I tried real hard not to pencil mark more than two cells in a box, and it seemed to make a lot of difference. I just worked my way up from 1-9 around the grid and it fell out quickly.
sir my time is 27.13
34 min.