Found your channel when you got blessed by the Algorithm a few days ago. I've watched it every day since. I didn't imagine sudoku could be so cool and soothing. Good job and thanks for all the videos!
this is really really really helpful. i found the channel just a week ago and i have learned so much. these solves are... how do i put it... i'd rather watch you solving sudoku for 1 nd half hour than watch sherlock episode.
I'm only 7 minutes in and already very thankful - I've been wondering what to do on harder puzzles once Schneider notation runs it's course - removing it and only noting doubles and triples looks like a great move!
Well, you solved it faster than I did. Took me a little over 42 minutes. I somehow stumbled on your channel a few days ago and I am so happy that I did!
7:16 Another way to solve the candidates 2n3 in Box 8: You can figure out where the 2 goes in column 4 because of the given 2 in box 5. Column 4 NEEDS a 2, and there's only one place left it can go. (r9c4)
Somehow TH-cam recommended that channel and I'm starting to get hooked! Up to 8:17 all numbers could be gotten by simple elimination. One only needed the 23 pair in row 9 and the Snyder marked 5s in row 5 and columns 7 and 9. The analysis following 8:17 is getting really complicated - I'm trying to find a simpler way, but it might not be possible. Thanks for the nice work!
Cracking The Cryptic, at 28:40 you find where a 4 can go, in r5c7. At first I was confused because I was wondering why a 4 couldn't go into r5c8, then I remembered that a 4 was not possible to go in that square based on the logic you described just a minute ago. That gave me an idea for a new notation. Taking notes when we've confidently removed a candidate from a square. It'd be nice to have a program that gave an option to put an "X" and marking a number red over notated candidates so we don't forget that that candidate is not possible in a specified square.
"Apologies, that's taken me 30 minutes to solve" I took an hour to give up, then have my app give me hints til I could finish it.... 20 hints later of 'logic' I'd never heard of I finally 'made it'.... If this was a few hundred years ago, I'd have you burned as a witch for that display of sorcery, haha.
At 21:30 you removed the 1’s due to the uniqueness of the (1,6) combo. Why did you remove the 1 from column five and not the 1 from column six? And why remove the 1 instead of the 6?
Brutal...absolutely brutal. Took me almost an hour, along with a Finned X-Wing, a Swordfish, a Finned Swordfish (!!!), a few XY chains, and about five uses of the ALS-XZ technique to break this one. Short of involving a Hidden Unique Rectangle or the forcing chain/nice loop strategies, this was about as complex a puzzle as I’ve come across...if it had used a Hidden Unique Rectangle and a discontinuous Nice Loop as well, it would have been epically difficult.
Simon I've been solving Sudokus, for mental exercise only not speed solving, since they came out in the UK. I'm still finding new techniques. Currently I do everything on paper, though I'd be grateful if you could supply a few URLs so that I could download and try any software that you recommend and save on my stationary. Perhaps you could include them under 'show more'. When solving newspaper based Sodukos where there is no space for pencil marks (at least for my eyesight) I found it useful to scribble for certain numbers a mini noughts and crosses board and represent possible positions with a dot. This made it much easier to scan for X wings etc. A similar dot pattern technique also helps to visualise Futoshikis. Regards Dave
If you are still looking, I highly recommend HoDoKu. It's one of the best pieces of software for Sudoku puzzles in my opinion. Highly customizable, hints if wanted, pencil marks are easy to use, and it comes in a very easy to use UI where you can build and enter your own puzzle values from another source.
Tried the puzzle twice and still came up short. Thanks for uploading this video solve, really learned and improved my solving technique with this puzzle
I found this to be a funny puzzle, because for the first 8 or 9 minutes it honestly seemed pretty straight forward. Then all of a sudden it hit a grinding halt and it took several different pieces of logic to slowly restrict until you got a single square.
Apparently it got reevaluated up to 120; that's what Duncan's had it as when I pulled it up tonight. I have never gotten to watch someone work through an example of APE before -- that was seriously helpful.
When you ruled that the 19 and the 29 in the 7th column had to not be a 1 and 2, I think you could easily have removed nines from all the squares with nines in that column other than those two squares. You could equally see why the 5th row, 7th column box could not be a 2, as it causes an equal problem as the one that was originally displayed, at 15:06.
Fantastic tutoring! I learn way more from these extreme puzzles. It would be quite advantageous if you establish at least one day each week for the advanced solvers.
Duncans solver is great but it would benefit from having the shift button switch between big and little numbers or holding shift down to enter little numbers. I would never play on my PC any other way if it had that.
I've actually attempt a sudoku from a book and got to a situation where there wasn't a unique solution! It was the same as the 1 and 6 pattern but with 5's and 8's. I solved the entire rest of the puzzle and that was all that was left, I was so confused 😅
I solved this in excel before watching. I didn't have to use any of the chain stuff on my solve. I thoroughly did all the Snyder notes, then looked for singles, doubles, etc
@@weixianng Snyder at first, then filling in notes for each possibility in each cell after that was exhausted. some singles and doubles stood out from that
This is one of the discouraging sudokus, when you want to advance. Would be nice if you would explain more of what you do when you think and move the mouse :)
Simon, I'm curious about something. If you rotate entire rows and columns, and rows and columns of blocks, you get a different-looking but essentially the same puzzle. Further, if you change the numbers around, it would still be essentially the same ("topologically equivalent"). Do you think you'd recognize that two very different-looking puzzles of this level of difficulty are topologically equivalent if you were to do them one after the other?
Just found your channel. Does any of you solve them by first putting in all number 1 in all squares, then number 2 etc? Thats how I solve sudoku. But sometimes I run in to a place where theres no longer any squares where only one number can be placed .... I need some sort of rule to get through that :)
Greetings. Simon, please help. Firstly, love your videos. Secondly, I try to complete the puzzle, and then follow your logic and tecniques. I learn alot. Anyway, i made a typo with the 6 in R3C9 and transcribed it to my paper grid to R2C9. A completely different puzzle obviously. I "solved it" but came out with an interesting dilemma. Two separate apps online provided 2 different solutions, neither if which were nine. And most interestingly, I concluded with a 2-4 matching pair x wing at positions R2C78 and R5C78. No matter where the 2 and 4 are placed, everything is correct. I've scanned the entire field and there are no duplicates ANYWHERE! Would you kindly investigate and see what you come up with, or perhaps comment on how I ended up with 2-4 matching pair xwing? I thought the title of "Descent to Madness" was appropriate. Cheers! Adam, SLC, UT USA
Man I ran into CtC in 2020 this is the first time I've really delved this far into your back catalog and these early videos are really slow compared to the modern ones and quite a bit rougher.
I'm confused by the uniqueness thing... You removed the 1s from c5/r1 and r3, could you have removed the 6s instead? How do you decide which numbers aren't unique when you have 4 lots of 2 digits?
Great video! Off topic, but are any of you or any acquaintances interested in or involved with nonograms? I’m a much bigger fan of picross and the like, and I’ve picked up an enormous amount from just independent puzzle solving, but I’m seeking some sort of coaching on more advanced techniques and how to implement them, and it’s been pretty hard to find anything beyond what I know (except puzzles! always easier to find puzzles beyond my grasp than to extend my grasp)
Of course: briefly here: Snyder notation (named after 3-time world Sudoku champion Thomas Snyder) is a technique where you add pencil-marks in 3x3 blocks where a number can ONLY go in 2 positions in that 3x3 block.General pencil marks mark in cells ALL the possible candidates that can go in that cell. (ie MUCH more comprehensive notation than Snyder notation). Each method has its uses. For any championship level puzzle and any puzzle up to a level of difficulty like the NYT Hard Sudoku, I would recommend Snyder notation. For the more esoteric difficulties that can be found on some apps (+ the diabolical Sudoku in The Daily Telegraph) then my preference is to start with Snyder notation and move towards the General method mentioned above.
Good. Thank you. I think I’m beginning to see. About the general pencil marks, I’m still unsure exactly. I’m thinking you don’t mean that they mark ”all the possible candidates” in the sense that: whenever there are general pencil marks in a cell, those are “all the possible candidates” i.e. there are no more possible candidates? So I’m wondering if maybe another way to say it would be that a general pencil mark in a cell marks “one of the possible candidates for that cell”?
@@nathanialblower9216 I think the idea is that once you cannot 'see' any obvious solutions for a cell, you go on to pencil marking... if you use 'General' pencil marking you must then pencil in ALL possible candidates for a cell - if you missed any out there wouldn't be much point in doing it I guess?
The best one, and I tried a lot, is enjoysudoku, without any doubt. It is worth buying the complete one, as you can enter puzzles from newspapers or other apps. Enjoy!!! 😜
Mon ami, didn’t it briefly show the solution when the computer “graded” it? Shouldn’t you like avert your eyes or something? You’re pretty sure none of that creeps into your subconscious I guess?
I don't even know what the symbols mean I'm afraid. You're right it could help if I did I suppose but, hopefully, you can see by the amount of time it takes me to solve it that I've not used aids!!
@@CrackingTheCryptic thats not really how the "subconcious" works in real life anyway. im guessing you dont have a eidetic memory either. so you're fine ^^
@ 0:54 those symbols look like the solution right? Right there in the puzzle board itself, no? As for using aides, I agree; but it would be interesting if brief exposure to the solution like that had some statistical bearing, you might say, such that it could serve as an “aide” you don’t even know you “use”. Also, please don’t take me too seriously about this :) Also, love the channel!
I feel like even if you had the solution from the beginning, it wouldn't help that much because you would still have to argue logically, which I could imagine would be made harder by knowing the answer!
Found your channel when you got blessed by the Algorithm a few days ago. I've watched it every day since. I didn't imagine sudoku could be so cool and soothing. Good job and thanks for all the videos!
I agree! I've taken to watching these videos in bed before I sleep. It's very zen.
I don't leave comments often. This is honestly a good watch. 30 minutes or even longer I don't mind. You have absolutely superb logic.
this is really really really helpful. i found the channel just a week ago and i have learned so much. these solves are... how do i put it... i'd rather watch you solving sudoku for 1 nd half hour than watch sherlock episode.
i appreciate the visuals
Thank you for bringing me back to my love of Sudoku. I am really enjoying learning these logic tricks to solving them.
Awesome! I've been stuck on a few very hard ones like this, and seeing how you work it out really helps!
I'm only 7 minutes in and already very thankful - I've been wondering what to do on harder puzzles once Schneider notation runs it's course - removing it and only noting doubles and triples looks like a great move!
Well, you solved it faster than I did. Took me a little over 42 minutes. I somehow stumbled on your channel a few days ago and I am so happy that I did!
7:16 Another way to solve the candidates 2n3 in Box 8: You can figure out where the 2 goes in column 4 because of the given 2 in box 5. Column 4 NEEDS a 2, and there's only one place left it can go. (r9c4)
Nice logic. I enjoyed it. I hope i can apply some of these tactics to my puzzles in the near future. Looking forward to the next vieo!
ah, the uniqueness trick is something ive never considered, thanks
I have watched you again and again complete he solve on this puzzle. I still enjoy the re-runs
Your logic in catching these pieces (aligned pair, Y wing, etc) is just astounding!
Somehow TH-cam recommended that channel and I'm starting to get hooked! Up to 8:17 all numbers could be gotten by simple elimination. One only needed the 23 pair in row 9 and the Snyder marked 5s in row 5 and columns 7 and 9. The analysis following 8:17 is getting really complicated - I'm trying to find a simpler way, but it might not be possible. Thanks for the nice work!
Well done Simon! Always learning from your expertise. Thank you.
Thanks. Spotting them is the key.
Cracking The Cryptic, at 28:40 you find where a 4 can go, in r5c7. At first I was confused because I was wondering why a 4 couldn't go into r5c8, then I remembered that a 4 was not possible to go in that square based on the logic you described just a minute ago. That gave me an idea for a new notation. Taking notes when we've confidently removed a candidate from a square. It'd be nice to have a program that gave an option to put an "X" and marking a number red over notated candidates so we don't forget that that candidate is not possible in a specified square.
"Apologies, that's taken me 30 minutes to solve"
I took an hour to give up, then have my app give me hints til I could finish it.... 20 hints later of 'logic' I'd never heard of I finally 'made it'....
If this was a few hundred years ago, I'd have you burned as a witch for that display of sorcery, haha.
First time solving along, I really did get a lot more out of it!
At 21:30 you removed the 1’s due to the uniqueness of the (1,6) combo. Why did you remove the 1 from column five and not the 1 from column six? And why remove the 1 instead of the 6?
You're not slow, you're amazing. 🇺🇸🇺🇸🇺🇸
Brutal...absolutely brutal. Took me almost an hour, along with a Finned X-Wing, a Swordfish, a Finned Swordfish (!!!), a few XY chains, and about five uses of the ALS-XZ technique to break this one. Short of involving a Hidden Unique Rectangle or the forcing chain/nice loop strategies, this was about as complex a puzzle as I’ve come across...if it had used a Hidden Unique Rectangle and a discontinuous Nice Loop as well, it would have been epically difficult.
That was really fun! Thanks!
Simon I've been solving Sudokus, for mental exercise only not speed solving, since they came out in the UK. I'm still finding new techniques. Currently I do everything on paper, though I'd be grateful if you could supply a few URLs so that I could download and try any software that you recommend and save on my stationary. Perhaps you could include them under 'show more'.
When solving newspaper based Sodukos where there is no space for pencil marks (at least for my eyesight) I found it useful to scribble for certain numbers a mini noughts and crosses board and represent possible positions with a dot. This made it much easier to scan for X wings etc. A similar dot pattern technique also helps to visualise Futoshikis.
Regards
Dave
If you are still looking, I highly recommend HoDoKu. It's one of the best pieces of software for Sudoku puzzles in my opinion. Highly customizable, hints if wanted, pencil marks are easy to use, and it comes in a very easy to use UI where you can build and enter your own puzzle values from another source.
Thank the TH-cam gods for helping me find your channel
Tried the puzzle twice and still came up short. Thanks for uploading this video solve, really learned and improved my solving technique with this puzzle
I found this to be a funny puzzle, because for the first 8 or 9 minutes it honestly seemed pretty straight forward. Then all of a sudden it hit a grinding halt and it took several different pieces of logic to slowly restrict until you got a single square.
Simon: "116 is slightly daunting."
This is what I call english understatement.
Apparently it got reevaluated up to 120; that's what Duncan's had it as when I pulled it up tonight. I have never gotten to watch someone work through an example of APE before -- that was seriously helpful.
When you ruled that the 19 and the 29 in the 7th column had to not be a 1 and 2, I think you could easily have removed nines from all the squares with nines in that column other than those two squares. You could equally see why the 5th row, 7th column box could not be a 2, as it causes an equal problem as the one that was originally displayed, at 15:06.
Fantastic tutoring! I learn way more from these extreme puzzles. It would be quite advantageous if you establish at least one day each week for the advanced solvers.
Come back in six months and Simon will have no hair left.
Thanks, I learned a lot.
Duncans solver is great but it would benefit from having the shift button switch between big and little numbers or holding shift down to enter little numbers. I would never play on my PC any other way if it had that.
Kai Green
In the most recent version, you can right click or press B to switch between big and little numbers.
Could you put a link to maybe a Google sheets prepared with the puzzle on read only for us to copy and try?
those wings!!!!
I've actually attempt a sudoku from a book and got to a situation where there wasn't a unique solution! It was the same as the 1 and 6 pattern but with 5's and 8's.
I solved the entire rest of the puzzle and that was all that was left, I was so confused 😅
With a title like that, you've gotta watch!
What software application are you using for your sudoku?
He's using Duncan's Sudoku Solver.
Manuel, which one because I can't find the one that allows big and little notation. Cheers
I solved this in excel before watching. I didn't have to use any of the chain stuff on my solve. I thoroughly did all the Snyder notes, then looked for singles, doubles, etc
You shit serious? Just snyder got you through it?
@@weixianng Snyder at first, then filling in notes for each possibility in each cell after that was exhausted. some singles and doubles stood out from that
It took me three hours to fail miserably. Had to learn about chains and uniqueness.
great video.
Excellent thanks
Minor but, Bottom right box was all pairs so no need to abandon the Snyder notation and you included some impossible 7s, and an 8
Which tool are you using onscreen to show the sudoku puzzles?
This is one of the discouraging sudokus, when you want to advance.
Would be nice if you would explain more of what you do when you think and move the mouse :)
what software is he using?
How do you know the 1 is the problem at 20:40 and not the 6
Cause 6 cannot be in any other position by simple sudoku rules.
What is the app used to play soduku?
Simon, I'm curious about something. If you rotate entire rows and columns, and rows and columns of blocks, you get a different-looking but essentially the same puzzle. Further, if you change the numbers around, it would still be essentially the same ("topologically equivalent").
Do you think you'd recognize that two very different-looking puzzles of this level of difficulty are topologically equivalent if you were to do them one after the other?
That was a hideous puzzle, thanks for taking us through it!
What software is this?
I got stuck at exactly the same part. Churned for a bit, and then tried to do some coloring and ended up stumbling on the solution which I hate. :(
Just found your channel. Does any of you solve them by first putting in all number 1 in all squares, then number 2 etc? Thats how I solve sudoku. But sometimes I run in to a place where theres no longer any squares where only one number can be placed .... I need some sort of rule to get through that :)
What software is being used?
Greetings. Simon, please help.
Firstly, love your videos. Secondly, I try to complete the puzzle, and then follow your logic and tecniques. I learn alot. Anyway, i made a typo with the 6 in R3C9 and transcribed it to my paper grid to R2C9. A completely different puzzle obviously. I "solved it" but came out with an interesting dilemma. Two separate apps online provided 2 different solutions, neither if which were nine. And most interestingly, I concluded with a 2-4 matching pair x wing at positions R2C78 and R5C78. No matter where the 2 and 4 are placed, everything is correct. I've scanned the entire field and there are no duplicates ANYWHERE! Would you kindly investigate and see what you come up with, or perhaps comment on how I ended up with 2-4 matching pair xwing? I thought the title of "Descent to Madness" was appropriate. Cheers!
Adam, SLC, UT USA
Once again, i spend an extra ten minutes just keeping up. (Pause & rewind!)
Man I ran into CtC in 2020 this is the first time I've really delved this far into your back catalog and these early videos are really slow compared to the modern ones and quite a bit rougher.
You should try live streaming this sometime!
I don't understand what you mean when you say the 6s are aligned. Also, both cells have 1s and 6s, why only remove the 1s and not the 6s also?
I'm confused by the uniqueness thing... You removed the 1s from c5/r1 and r3, could you have removed the 6s instead? How do you decide which numbers aren't unique when you have 4 lots of 2 digits?
Never mind, I tried it and answered my own question!
I'm about average at this but I thought this was easy. Completely straightforward, no X wings, XY wings, nothing.
I didn’t understand the uniqueness. Why say the 1 wouldn’t go there why not the 6 thank you brilliant solve
that misplaced "maybe"8 on the corner kept bugging and distracting me the whole time, i had to go back a few seconds in several places
Great video! Off topic, but are any of you or any acquaintances interested in or involved with nonograms? I’m a much bigger fan of picross and the like, and I’ve picked up an enormous amount from just independent puzzle solving, but I’m seeking some sort of coaching on more advanced techniques and how to implement them, and it’s been pretty hard to find anything beyond what I know (except puzzles! always easier to find puzzles beyond my grasp than to extend my grasp)
A puzzle takes as long as needed. Don't worry about the length of the video. This one doesn't look like a 116, though.
What would happen if you spot the XYZ-wing in the centre at 11 minutes or thereabout?
Just tried it. Answer not a lot! Still needed the empty rectangle on 8s in block 1 (A most useful technique tutored by your good self.)
Could you say what exactly are the rules of this “pencil”/“Schneider” notation (you use those two terms interchangeably at least sometimes right?)
Of course: briefly here: Snyder notation (named after 3-time world Sudoku champion Thomas Snyder) is a technique where you add pencil-marks in 3x3 blocks where a number can ONLY go in 2 positions in that 3x3 block.General pencil marks mark in cells ALL the possible candidates that can go in that cell. (ie MUCH more comprehensive notation than Snyder notation). Each method has its uses. For any championship level puzzle and any puzzle up to a level of difficulty like the NYT Hard Sudoku, I would recommend Snyder notation. For the more esoteric difficulties that can be found on some apps (+ the diabolical Sudoku in The Daily Telegraph) then my preference is to start with Snyder notation and move towards the General method mentioned above.
Good. Thank you. I think I’m beginning to see.
About the general pencil marks, I’m still unsure exactly. I’m thinking you don’t mean that they mark ”all the possible candidates” in the sense that: whenever there are general pencil marks in a cell, those are “all the possible candidates” i.e. there are no more possible candidates?
So I’m wondering if maybe another way to say it would be that a general pencil mark in a cell marks “one of the possible candidates for that cell”?
@@nathanialblower9216 I think the idea is that once you cannot 'see' any obvious solutions for a cell, you go on to pencil marking... if you use 'General' pencil marking you must then pencil in ALL possible candidates for a cell - if you missed any out there wouldn't be much point in doing it I guess?
Thank you for the original question, was going to ask the same.
@@CrackingTheCryptic The bit I was missing here was that Snyder applies only within the box - ta ;)
This has nothing on the monsters that were shown on the channel (1h+ video) in 2020.
I ALMOST got it! I hate 7.
Any good Android sudoku apps?
The best one, and I tried a lot, is enjoysudoku, without any doubt. It is worth buying the complete one, as you can enter puzzles from newspapers or other apps. Enjoy!!! 😜
@@alfredotrotta5915, thank you!
I solved it, but I had to guess on one square
Took you 13 mins to get to where I am at the hour mark, sigh
Mon ami, didn’t it briefly show the solution when the computer “graded” it? Shouldn’t you like avert your eyes or something? You’re pretty sure none of that creeps into your subconscious I guess?
I don't even know what the symbols mean I'm afraid. You're right it could help if I did I suppose but, hopefully, you can see by the amount of time it takes me to solve it that I've not used aids!!
@@CrackingTheCryptic thats not really how the "subconcious" works in real life anyway. im guessing you dont have a eidetic memory either. so you're fine ^^
@ 0:54 those symbols look like the solution right? Right there in the puzzle board itself, no? As for using aides, I agree; but it would be interesting if brief exposure to the solution like that had some statistical bearing, you might say, such that it could serve as an “aide” you don’t even know you “use”.
Also, please don’t take me too seriously about this :)
Also, love the channel!
I feel like even if you had the solution from the beginning, it wouldn't help that much because you would still have to argue logically, which I could imagine would be made harder by knowing the answer!
vocalnerd interesting!
116 XD
it isnt ^ ^