I think it's interesting how the number of given digits in a Sudoku puzzle seems to have little impact on its difficulty. None of the 17-digit Sudokus that I've met so far, including this one, were too difficult to be honest. Yet the Sudoku in the video where Simon first introduced the revolutionary 'permutations' technique was one of the most brutally difficult ones I've ever solved, despite the relatively generous number of givens.
Where you first use uniqueness (around 7:30), you can actually fix the 2/4 pair in the bottom left. The 4/9 pair in the right center box with the 2 in row 4 means a 2 can only be in col 8 in that box. That puts a 2 in row 8 in the bottom right box, which puts a 4 in r8c1 and a 2 in r9c1. This was way easier than I was expecting for a 17 puzzle!
Just pointing out you typed "2 can only be in col 8" , I'm sure you meant "col 7" Easy to place a wrong number in an explanation, I'm done it myself many times.
Didn't need to use any uniqueness in my solution. Funny thing was that when I put that into my solver it told me that it was impossible. The minute I put the naked 5 in r3c3 the solver told me that the puzzle was easy. And after that I just strated to fill in possible candidates and almost immediately noticed that when I fill in another box the possibilities there solve some of the numbers in other boxes. So that way I first filled in the first three columns and starting with box 8 worked my way back up filling possibilities and resolving what they did in the other boxes. In the end I had the puzzle solved. Nothing fancy just not doing traditional schneider but fill in all possibilities a box has.
@@JasperJanssen Uniqueness isn't needed to solve this. The steps he shows around ~7:55, immediately after using uniqueness, actually didn't depend at all on his uniqueness argument at 7:30. As shown, the argument for the 2 being in box 6, column 7 fixes the 4 and 2 in the bottom left of the grid and puts the 8 in the top left corner of box 9. This leaves 1 and 2 as the only available numbers in row 7, and one of those is blocked by the given 2 in column 6. The 2 that you've now placed in box 8 then bypasses the uniqueness argument entirely without needing to argue "this is the solution because we know one unique solution exists," which isn't nearly as elegant.
I used the New York Times Hard Sudoku technique right off the bat, and found the 2-4-9 in the upper left box forced those digits into exactly 3 places in column 1. That was the entry point for me, after that it fell into place with only one naked cell.
That was the fastest time I ever solved a puzzle presented on this channel. I'm learning :o Anyways 07:05 for me. Pretty straight forward and easy. Thank god there was no empty rectangle involved.
Nice puzzle and a nice solve. I didn't see the uniqueness. I found the twos in the middle right box, which led me to the 8 in the top row of the lower right box which provided me the 2. in the lower middle box. I love watching you and Simon. I have learned a lot and my times with puzzles have improved, a lot less staring, though I am not world-class speed, I now am mr=ore confident when doing difficult puzzles. Supporting on Patreon is inexpensive, and I love the Sandwich Sudoku game on my PC.
This puzzle was a straightforward solve, probably at the NYT Medium level. Much easier to do than their Hard puzzles, with no hidden tricks and every clue easy to find.
took me about twice as long as Mark, so quite approachable by cracking-the-cryptic standards; using uniqueness was not necessary - there was still a pointing pair of 2s in box 6 to exploit which gives you in the end the 2 in box 8.
I tend to solve Sudoku puzzles at a leisurely pace, so it takes me a lot longer than Simon or Mark. Maybe solving it without invoking uniqueness contributed to my time as well.
Same time. An enjoyable diversion. Before watching this channel I would have thought this was impossible garbage so I'm pretty pleased with my progress and thankful for the lads.
(Typing a second time because UA-cam logged me out.) Took about 30 minutes, not sure exactly since there's no pause for the timer for when I stepped away. Used a logic chain in r8c1 to eliminate a 2 as a candidate. Used logic just in box 6 to prove the 2 was restricted to column 7 fixing an 8 in r7c7. Used another logic chain to eliminate a 2 from r3c5. Then put a 2 in r3c4 and finished the puzzle. Slightly challenging but not too difficult.
7:30 - 7:36 How were the twos in box 8, column 4 ruled out due to uniqueness? I don’t see how the twos over in box 7 could rule out the possibility of a two being in column 4.
Because then you'd have a 24 pair in both column 1 and 4 in the same exact two rows. And that would mean that the sudoku would have two solutions, because you could put a 2 in either row 8 or 9 and still come out with a ''correct'' solution. But any good sudoku has only ONE solution. So whenever you solve sudokus, keep in mind that you can never have a 2 pairs in the same rows/columns, because that would mean you'd get two possible solutions to the puzzle.
I may be late to this conversation, but I can't help but notice that since the minimum. number of clues n for a unique sudoku solution is n = 9 squared minus 8 squared = 17, can we generalize that for a grid of size T that observes “sudoku rules” that n = T squared minus (T-1) squared or is that just a coincidence?
Tried it before watching the video and I got up to the uniqueness trick before getting stuck, just couldn't see it. Once you showed it, I managed to go back and finish. Nice puzzle
Lately, when not solving for time, I've stopped using uniqueness. I've always found some other logic that could solve the puzzle and if I used uniqueness, I would have missed it. In this puzzle, the 2 in R4 C6 interacts with the 4/9 pair in the middle right box to lock 2 into column 7 of that box. That in turn locks the 2 into row 8 of the bottom right box. Easy to see from here that 2 must be in R7 C5 without ever using uniqueness.
@@04LightningFan Oh nice, I didn't see it at all at the time but looking back it actually replaces the uniqueness entirely. Nice find and thanks for the hint!
Did it in 14:26 with a quick pee break in there. Used my own formula with my own ghost & double ghost projections method. I may actually record myself doing it and talk through my formula use to solve but its not hard enough to prove my formula's prowess.
I used an Apple app called Sudoku World by Zelnut for a while. All their “Expert” level puzzles are 17 givens. As someone has stated there is no correlation between givens and difficulty. I quit using this app as the puzzles seemed not very interesting after a while.
17 digits is so far the least number of digits needed to solve a regular sudoku. Mathematically, a 16 digit sudoku have not yet been proven to have a unique solution.
You can't browse the cracking the cryptic website for sudoku. However almost every day there is a sudoku on their youtube page and all the recent videos have a link so you can try to solve it.
@@ArthurSavage Nah, I thought maybe I could find something easier for me. These are way too difficult. I know there are many sudoku apps out there but I couldn't find any with such functionalities like this one, e.g. marking all possible numbers.
It'd be nice if they made one that started blank and let you put in givens before starting the timer. Then you could transcribe any sudoku into it and use it.
What it means is that if u have locked 24 in C1 R8 and R9. And also locked 24 in C4 in R8 and R9 u can get 2 different solutions to the puzzle, because no matter the order of the 2 and 4 u still get a solve. So he implies that the sudoku has 1 solution only, therefore as 4 is already locked in C4 R8/9 u can't put a 2 there and that's how he gets the position of that 2
i must disagree with you. if you didn't use uniqueness on 2 and 4 at row 89, i think it's harder. i found the uniqueness but i prefer on doing with logical way. took me long enough to spot the 6 at row 4 col 8
Sure... add some extra clues to a puzzle with fewer givens and you get something easier, that’s hardly a mind blowing observation. The only puzzles I think are worth talking about are those where you can’t remove clues without not having a unique solution. I can give you any number of 30+ given puzzles which are very difficult, and any number of
I think it's interesting how the number of given digits in a Sudoku puzzle seems to have little impact on its difficulty. None of the 17-digit Sudokus that I've met so far, including this one, were too difficult to be honest.
Yet the Sudoku in the video where Simon first introduced the revolutionary 'permutations' technique was one of the most brutally difficult ones I've ever solved, despite the relatively generous number of givens.
Where you first use uniqueness (around 7:30), you can actually fix the 2/4 pair in the bottom left. The 4/9 pair in the right center box with the 2 in row 4 means a 2 can only be in col 8 in that box. That puts a 2 in row 8 in the bottom right box, which puts a 4 in r8c1 and a 2 in r9c1.
This was way easier than I was expecting for a 17 puzzle!
Just pointing out you typed "2 can only be in col 8" , I'm sure you meant "col 7"
Easy to place a wrong number in an explanation, I'm done it myself many times.
He does do exactly this at 7:57, and of course the 2 and 9 he fixed a few seconds before in box 2 had no bearing on that logic.
Didn't need to use any uniqueness in my solution. Funny thing was that when I put that into my solver it told me that it was impossible. The minute I put the naked 5 in r3c3 the solver told me that the puzzle was easy. And after that I just strated to fill in possible candidates and almost immediately noticed that when I fill in another box the possibilities there solve some of the numbers in other boxes. So that way I first filled in the first three columns and starting with box 8 worked my way back up filling possibilities and resolving what they did in the other boxes. In the end I had the puzzle solved. Nothing fancy just not doing traditional schneider but fill in all possibilities a box has.
I didn't need to resort to uniqueness - found it fairly straight forward for a change!, didnt need any crazy x,y or empties to finish it.
Weird, the uniqueness point was *exactly* where I stalled.
Neither did I, because of the pointing 2s in box six creating pointing 2s in box nine.
@@JasperJanssen Uniqueness isn't needed to solve this. The steps he shows around ~7:55, immediately after using uniqueness, actually didn't depend at all on his uniqueness argument at 7:30. As shown, the argument for the 2 being in box 6, column 7 fixes the 4 and 2 in the bottom left of the grid and puts the 8 in the top left corner of box 9. This leaves 1 and 2 as the only available numbers in row 7, and one of those is blocked by the given 2 in column 6. The 2 that you've now placed in box 8 then bypasses the uniqueness argument entirely without needing to argue "this is the solution because we know one unique solution exists," which isn't nearly as elegant.
some logical leaps I could not follow. But was still fun to watch. Thanks
I used the New York Times Hard Sudoku technique right off the bat, and found the 2-4-9 in the upper left box forced those digits into exactly 3 places in column 1. That was the entry point for me, after that it fell into place with only one naked cell.
That was the fastest time I ever solved a puzzle presented on this channel. I'm learning :o
Anyways 07:05 for me. Pretty straight forward and easy. Thank god there was no empty rectangle involved.
Not only are there only 17 givens, there is also a number - 8 - missing.
Despite this, it was quite easy.
This was straight forward and clearly show why few givens are not necessarily hard.
I've been watching for about 2 weeks now and this is the first one I've managed to solve. :) 34:36
34:06, pretty smooth and no need for fancy technique or uniqueness
7:04 Uniqueness? What sorcery is this?
Solved it in 30 minutes. These 17 givens sudokus are my bane.
Nice puzzle and a nice solve. I didn't see the uniqueness. I found the twos in the middle right box, which led me to the 8 in the top row of the lower right box which provided me the 2. in the lower middle box. I love watching you and Simon. I have learned a lot and my times with puzzles have improved, a lot less staring, though I am not world-class speed, I now am mr=ore confident when doing difficult puzzles. Supporting on Patreon is inexpensive, and I love the Sandwich Sudoku game on my PC.
This puzzle was a straightforward solve, probably at the NYT Medium level. Much easier to do than their Hard puzzles, with no hidden tricks and every clue easy to find.
took me about twice as long as Mark, so quite approachable by cracking-the-cryptic standards; using uniqueness was not necessary - there was still a pointing pair of 2s in box 6 to exploit which gives you in the end the 2 in box 8.
I tend to solve Sudoku puzzles at a leisurely pace, so it takes me a lot longer than Simon or Mark. Maybe solving it without invoking uniqueness contributed to my time as well.
Just under 14 minutes for me, and a nice exercise, too. It is the kind of puzzle I find complex, rather than hard.
Same time. An enjoyable diversion.
Before watching this channel I would have thought this was impossible garbage so I'm pretty pleased with my progress and thankful for the lads.
did in one try, 20 minutes =) not a pro but makes me happy to share my result...now i`ll see you doing`t!!
Took me 30 minutes with no hints, better than last time I did one from this channel :D
(Typing a second time because UA-cam logged me out.) Took about 30 minutes, not sure exactly since there's no pause for the timer for when I stepped away. Used a logic chain in r8c1 to eliminate a 2 as a candidate. Used logic just in box 6 to prove the 2 was restricted to column 7 fixing an 8 in r7c7. Used another logic chain to eliminate a 2 from r3c5. Then put a 2 in r3c4 and finished the puzzle. Slightly challenging but not too difficult.
Took me about 30 minutes. I'm amazed I even succeeded!! Baby steps, but it's progress
7:30 - 7:36 How were the twos in box 8, column 4 ruled out due to uniqueness? I don’t see how the twos over in box 7 could rule out the possibility of a two being in column 4.
Because then you'd have a 24 pair in both column 1 and 4 in the same exact two rows. And that would mean that the sudoku would have two solutions, because you could put a 2 in either row 8 or 9 and still come out with a ''correct'' solution. But any good sudoku has only ONE solution. So whenever you solve sudokus, keep in mind that you can never have a 2 pairs in the same rows/columns, because that would mean you'd get two possible solutions to the puzzle.
I see. Thank you!
@@r0bw00d No worries! Glad I could help.
I may be late to this conversation, but I can't help but notice that since the minimum. number of clues n for a unique sudoku solution is
n = 9 squared minus 8 squared = 17,
can we generalize that for a grid of size T that observes “sudoku rules” that
n = T squared minus (T-1) squared
or is that just a coincidence?
Did it without the uniqueness, nice Fri brain tickler. Have a good long weekend to all in Canada.
Tried it before watching the video and I got up to the uniqueness trick before getting stuck, just couldn't see it. Once you showed it, I managed to go back and finish. Nice puzzle
Lately, when not solving for time, I've stopped using uniqueness. I've always found some other logic that could solve the puzzle and if I used uniqueness, I would have missed it. In this puzzle, the 2 in R4 C6 interacts with the 4/9 pair in the middle right box to lock 2 into column 7 of that box. That in turn locks the 2 into row 8 of the bottom right box. Easy to see from here that 2 must be in R7 C5 without ever using uniqueness.
@@04LightningFan Oh nice, I didn't see it at all at the time but looking back it actually replaces the uniqueness entirely. Nice find and thanks for the hint!
Did it in 14:26 with a quick pee break in there. Used my own formula with my own ghost & double ghost projections method. I may actually record myself doing it and talk through my formula use to solve but its not hard enough to prove my formula's prowess.
I managed to solve it with out using any fancy technique. Pencil makings do help a great deal in this puzzle
Finished with a 38:06, feel pretty good about that.
Yay excited for my daily dose of sudoku! :)
44:56, the first one I could solve by myself
7:33 sorcery I tell you!
this took me 20 minutes, Im getting better at sudoku if i do say so myself it used to take 40 mins a week ago
I used an Apple app called Sudoku World by Zelnut for a while. All their “Expert” level puzzles are 17 givens. As someone has stated there is no correlation between givens and difficulty. I quit using this app as the puzzles seemed not very interesting after a while.
40:00! I'm getting better!
19:10, my quickest solve yet!
Well just about the easiest Sudoku I've seen on your site. A few minutes. (You've beat me a fair few times)
7:30 I don't understand what he did there. I reasonably got everything he did up to that point.
26:04, seems hard, but easy once you know those techniques
15 minutes on the dot; nice simple one, didn't have to resort to any crazy shenanigans
The uniqueness trick was amazing, i solved it without it in 17' 55''. I guess is because all the tricks i am learning here
What took you 10 minutes took me 53... I'm amazed.
Nice got 17:15. Fun one
This one took me 12:45. I stumbled at a middle stage in the puzzle because I hadn't spotted a naked single.
13:33 no techniques used, getting close to Mark's time althought he'd get here probably about 4-5 minutes?
12:33. I don't think I used any advanced techniques at all. One of the satisfyingly easier ones~
That was easier than I thought it would be. 17 minutes
19 for me but only because i had to stop a few times. :)
Then I must have like 50 IQ.
It took me 53. I don't know any of the techniques professionals use, just pencil marking logic, so I think I did alright!
48:56 took me a while to find some 2's that could fairly easily be found
17 digits is so far the least number of digits needed to solve a regular sudoku. Mathematically, a 16 digit sudoku have not yet been proven to have a unique solution.
9:12 Wow, I think I outdid myself!
26:03 Missing so many obvious numbers. I hope I can get better.
I think this is the first time I've seen a uniqueness issue myself. I'm not sure whether I could have solved it otherwise.
I was looking for this and was not expected to get this many results. Did the sodoku took over an hour and fucked it up somewhere
A good challenge 11:50 for me
Can I solve other sudokus on this website, or only those that they give links to?
You can't browse the cracking the cryptic website for sudoku. However almost every day there is a sudoku on their youtube page and all the recent videos have a link so you can try to solve it.
@@ArthurSavage
Nah, I thought maybe I could find something easier for me. These are way too difficult.
I know there are many sudoku apps out there but I couldn't find any with such functionalities like this one, e.g. marking all possible numbers.
only those with links.
It'd be nice if they made one that started blank and let you put in givens before starting the timer. Then you could transcribe any sudoku into it and use it.
Finished this puzzle in 5min 31sec!
Whats the name of Mozarts Music in the intro?
en.wikipedia.org/wiki/Piano_Sonata_No._16_(Mozart)
That's gotta be the easier 17-clue puzzle ever.
Around 12 minutes without relying on x-wing stuff (I can't really use that technique anyway). Somehow expected I'd need longer.
I managed to solve this one in 39 minutes.
Took me 53, good job!
25:10 was my time. This one didn't seem all that difficult, even with me missing a few obvious numbers.
I finished this one in 19:47
10:07 for me. not bad
7:04 , pretty easy
took me 38min
Could somebody explain the uniqueness solve please
What it means is that if u have locked 24 in C1 R8 and R9. And also locked 24 in C4 in R8 and R9 u can get 2 different solutions to the puzzle, because no matter the order of the 2 and 4 u still get a solve. So he implies that the sudoku has 1 solution only, therefore as 4 is already locked in C4 R8/9 u can't put a 2 there and that's how he gets the position of that 2
Lucas Zupan thank you for taking the time to explain.
@@dougdavis8367 You are welcome :D
20m 11sec used a simple chain once
في الدقيقة 2.34 كيف عرفت ان الرقم 9 !!!! ؟؟؟ سيكون في هذه الخانة ؟
I was really slow today, finish in 43:51.
8:22 for this one. was very easy in my opinion. no complex logic at all
31 minutes. Wooooooooooooooooo!
Tried again and did it in 18:19 :)
15.56
Simple logic only and 17:07. I need to work on my solving skills, lol
34 minutes - not the best, but good for me :D
Huh, I thought it would be harder. Never judge a sudoku by its givens. Took me 15:16 to finish.
38 flat for me
BEST
This has 17000 views.
Great solve, but I didn't like the meta-argument of uniqueness.
An hour for me
32:24 - No uniqueness. Just plain sudoku and some doubles and triples.
91 mins ..omg
i must disagree with you. if you didn't use uniqueness on 2 and 4 at row 89, i think it's harder. i found the uniqueness but i prefer on doing with logical way. took me long enough to spot the 6 at row 4 col 8
It's only a couple extra steps via the effect the central box's 2 has on box 6 that he found soon after.
Number of givens has absolutely zero correlation with the difficulty level for sudoku. Zero!
@Fester Blats gotem coach
@Fester Blats, 81 givens would be easier 😏
Sure... add some extra clues to a puzzle with fewer givens and you get something easier, that’s hardly a mind blowing observation.
The only puzzles I think are worth talking about are those where you can’t remove clues without not having a unique solution. I can give you any number of 30+ given puzzles which are very difficult, and any number of
@@tomcollyer641, I wonder what the greatest number of givens there can be where you can't remove any without breaking uniqueness.
I always thought you'd need nested bifurcation to solve one with this few givens!