Some of the tutorials I have watched are so slow, they are torturous. In this, you immediately take care of the obvious cells. Thanks. The rest of the solution was very enlightening and for me, not too fast or too slow.
Thanks, for some time I have been trying to figure out how X wings work, but reading about them I've been left scratching my head. This is a very clear demonstration.
I loved the bit about 7 8 and 9..... isolating the 7&9 based on the fact they could not be in the column. Very nice, now I will have to remember that step.
Another way to look at it - if you pencil in 7 and 9 as the only options for row 3 column 3, given that 7 and 9 are also the only options for row 7 in the same column, the only option left for row 2 in column 3 is 8.
What I tend to do is get halfway or more into the puzzle and then realise I've got two 4's in one row. Then I carefully crumple up the puzzle so no one can see what I did and throw it in the bin.
Wasn't there another x-wing of 4's? Rows 4 and 8 and Columns 4 and 7? It may not have helped, but it was there at the same time as the other x-wing of 4's. Am I wrong? Would it have helped in the solution?
Normally, I start off with the numbers to see if I can align them in their respective boxes. 1, 2, 3 and so on up to 9. Once I've cycled through those, I look at the board to see what numbers from 1 - 9 are missing from rows and the individual boxes. If that process of elimination doesn't reveal the pattern to me, I then fill the empty spaces with the possible solutions. Usually, once I see the possibilities, I can see what isn't possible. A lot of times it involves logical thinking outside the box and knowing what you can't insert has a tendency to tell you what can. If that makes sense.
There seems to be a few folks out there who are just not grasping this technique. How about an "X Wings for Dummies" type of video? BTW, thank you, I really appreciate what you do.
Look at sudokuwiki.org -- Andrew Stuart's website -- there are complete explanations of each kind of logic used in solving sudoku puzzles, with examples, and he has published them in a book you can purchase at a very reasonable price.
thanks. I have been so very lost with trying to employ the help of X Wings and you gave me a better understanding, though their placement that you came up with seemed questionable, or hopeful .... So next round could you please explain a bit more as to why those were the correct choices for the X wings? Seems like a great tool and maybe tastier than chicken wings!
interesting, this xwing technique is the first not directly from the base rules I will need to integrate it to my program and may solve some cases where my program should make a guess and explore tree of solution . :-)
Yes that is right! Another 1 2 pair in r4c2 means that the puzzle would have two solutions, so that square must be the only other digit possible, an 8!
I put the above numbers into the on line Sudulo +Solutions site where I normally do Sudoko on my I pad and asked it to rate this puzzle. It said there were multiple answers (20 I think) for this one.This is a good site as u can copy in any sudoko and do it. it will generate the possiblecanadates for each square or u can pencil them in yourself. Would like to hear your comments.
May I ask what program, web page, or tool do you use for solving your puzzles? I use a paper form i made up but I like the way your program allows pencil marks and removes a mark when a cell uses a number in an intersecting cell.
With the greatest respect for Simon's Sudoku expertise, which I do not even begin to approach, he seems to have needlessly complicated the solving of this puzzle by introducing overlapping x-wings and other complicated logic. Here is a much simpler and faster solution: At the point where Simon finds himself at the 5:00 mark, I continued first by noting easily that the r1c9 cell can only be 2 or a 9. This quickly reduces the whole column 9 to cells containing no more than 2 numbers, and does the same for the lower left grid. At that point, I noticed a 3 x-wing in rows 3, 4 and columns 4, 8 (the 3 in r3C6 can be eliminated, since it would force two 3's in row 4). By eliminating the 3 from r3c6, it forces a 9 there, which in quick form solves the entire top 3 rows, and the rest of the puzzle in quick order. Simon gets to this same x-wing, but only at 14:45, after a long and complicated route with a pair of overlapping x-wings. One other point: At the 11:00 mark, Simon again uses complicated logic instead of a simpler method to prove that r2c3 is an 8. Since there already is a 7-9 in r7c3, and row 3 already has an 8, we have a 7-9 pair and that forces an 8 in r2c3.
definitely mind-opening for me. I got to the position 5:00 quite easily as i've solved many sudokus before, however got stuck then. Those x-Wings patterns will indeed improve my game. Thumbs up
Thanks, what program are you using? I'm still doing the pencil eraser thing! Is it possible to enter your own numbers? Start with a blank and enter your own puzzle?
I'm surprised you move away from Snyder notation as quickly as you do in this case. I solved this on paper quite quickly without (consciously) identifying an x-wing, just by following snyder notation, and then identifying a couple doubles and pairs. Overall it took relatively few pencil marks to solve (good, because I only had a pen, lol.)
I am new to this and I have a question, at 9:40 you pencil marked 1 -1 on the boxes, but how can you be so sure that the 9 you added at 9:47 is correct? Column 2 and 3 didn't have any 9 in them so one of those 1-1 could also contain 9. I can't follow the logic
The reason is that you need to focus on the possible numbers that could possibly go in to r9c4. Because of the triple on 4/6/7 already in row 9 this square is very limited indeed. In fact, it can only be a 1 or a 9 due to the other numbers in its row/column/3x3 block. So once I identify that there are the pencil-marked 1s you mention in either r9c2 or r9c3, I KNOW there cannot be a 1 in r9c4 anymore. So it must be a 9!
6:30 I don't get how he put the 2 at 6:30 :/ This is probably too advanced for me and he's clearly very good at recognizing the patterns, but I feel like he does too much steps in his head if like he said he's trying to make a "tutorial" out of this. But i get it that it must be boring if he went more basic for all of you who are experience at this. Thanks a lot anyway, I'll know where to look once I get better at this ;)
Pretty puzzle though I would only put it at 'moderate difficulty'. Didn't need X-wings to solve, just simple scanning of large boxes, rows & columns, together with identifying doubles & triples. Or am I missing the point? I enjoyed the presentation style.
Agreed it's a great puzzle but you only need to spot the x-wing on 3s and the position of the 8 in the first box in order to be able to solve it. I wonder how long it took for the author to compile the puzzle.
Hi, I realy enjoyed this but I would ask that you cut down on the very basic observations early on to allow you a little more time to explain the more advanced logic that comes into play later. Thanks once again as I am slowly grasping how to search for the x wing . An in depth explanation of it's use and why other notations can then be ignored. Thank You,
In the central 3x3 block at that point there are two cells containing pencil-marked 3 and 4 ie there is a pair. This pair interacts with the 2 I've just found in r5c9 and forces the 2 into r4c5.
Do you actually use notation "pencil marks" when you solve sudokus or is this simply for your audience to understand your thinking? I've cracked thousands of them over the years (including yours on pause before you went through your explanation) without using a single notation for available numbers. I simply keep all deduced number combos in my head as I get to them (like your 7/9 and 1/2 in the BL grid) as I go along and simply apply that as other limiting number options interact (like the 9/8/7 combo in TL grid) and then fill each correct number in as it occurs. I know its not cheating to write down possible number combos, etc. , but it somehow feels unsporting. Also, I find my methodology to be a much more streamlined process without all of that clutter trying to help me. :) Lastly, this x-wing concept is something I've come across as a natural recourse of repeatedly crunching numbers in combination over the years but I didn't know that it actually has a name or that it is a commonly recognized system of solution. I only knew that it worked, which was good enough for me... :)
I do more or less the same thing but copy the numbers into a fairly large grid and write the missing ones outside, gradually resolving the position with locked pairs (4/7) etc, like yourself. But I think this puzzle needed a bit extra. What really amazes me, though, is the fact that this is hand-written.
the jumping around of your highlighter... distracting as all get out.. cannot concentrate. I do easy sudoku and if there is numeral 4 or whatever in or on one level I jump down or up to the other level and keep doing that. This will fill in some few squares to get me started. Honestly sir this 'instructional' is ideal fiddling about for the self when alone … it's not at all, in the remotest sense a teaching tool …. it's not a " HOW TO" in this state of shall we say clutter. A lot of it can be slimmed down at time of editing...
Your solution is incorrect. Your first mistake was in placing the 4 in the center of the left-center square.. The left center square should (right to left and top to bottom) is 741,523,986
With respect, the 4 you mention is given at the start so I don't think it can be in the wrong place :). The numbers in grey are the starting numbers; the numbers in black are entries I make during my solve.
Patiently do difficult puzzles for another month, then come back to this. Repeat as necessary until it makes sense. It will. I probably would not have understood this a month ago. Hang in there iwona.
Dear Iwona, if there is one thing Simon CANNOT be accused of, and that is that he goes too fast! If I want careful detailed explanations, I always know I will get them here! Perhaps, my friend, the problem lies in the fact that Simon mostly does hard/fiendish and above. Therefore, there is a learning curve before anyone is ready for this site! Simon has to constantly strike the balance between being helpful and being boring!! Personally, I find he holds that balance very well. Thank you. Chris
Some of the tutorials I have watched are so slow, they are torturous. In this, you immediately take care of the obvious cells. Thanks. The rest of the solution was very enlightening and for me, not too fast or too slow.
I really enjoy the content
Thanks for the tip. I like the pace of your solutions.
Thanks, for some time I have been trying to figure out how X wings work, but reading about them I've been left scratching my head. This is a very clear demonstration.
I loved the bit about 7 8 and 9..... isolating the 7&9 based on the fact they could not be in the column. Very nice, now I will have to remember that step.
Another way to look at it - if you pencil in 7 and 9 as the only options for row 3 column 3, given that 7 and 9 are also the only options for row 7 in the same column, the only option left for row 2 in column 3 is 8.
Knowing its existence, and seeing its occurrence are two different things.
What I tend to do is get halfway or more into the puzzle and then realise I've got two 4's in one row. Then I carefully crumple up the puzzle so no one can see what I did and throw it in the bin.
I put a big X over it and write a sad face. :(
Wasn't there another x-wing of 4's? Rows 4 and 8 and Columns 4 and 7? It may not have helped, but it was there at the same time as the other x-wing of 4's. Am I wrong? Would it have helped in the solution?
Normally, I start off with the numbers to see if I can align them in their respective boxes. 1, 2, 3 and so on up to 9. Once I've cycled through those, I look at the board to see what numbers from 1 - 9 are missing from rows and the individual boxes. If that process of elimination doesn't reveal the pattern to me, I then fill the empty spaces with the possible solutions. Usually, once I see the possibilities, I can see what isn't possible. A lot of times it involves logical thinking outside the box and knowing what you can't insert has a tendency to tell you what can. If that makes sense.
Much better than the guess method. I need help with the x-wing thing also.
There seems to be a few folks out there who are just not grasping this technique. How about an "X Wings for Dummies" type of video? BTW, thank you, I really appreciate what you do.
Look at sudokuwiki.org -- Andrew Stuart's website -- there are complete explanations of each kind of logic used in solving sudoku puzzles, with examples, and he has published them in a book you can purchase at a very reasonable price.
@@zwqcv3jc thanks for linking that
thanks. I have been so very lost with trying to employ the help of X Wings and you gave me a better understanding, though their placement that you came up with seemed questionable, or hopeful ....
So next round could you please explain a bit more as to why those were the correct choices for the X wings? Seems like a great tool and maybe tastier than chicken wings!
A beautiful puzzle, beautifully solved. Thank you
How did you know to look for x wings on 4 and 6?
interesting, this xwing technique is the first not directly from the base rules I will need to integrate it to my program and may solve some cases where my program should make a guess and explore tree of solution . :-)
Hi! Is there a way you can upload this puzzle to your software and put it in the description?
Thanks a lot!
Your Sudoku app is very useful. Can you tell me where I can download it from, please?
@11:27 can we use uniqueness to deduce value 8 in row 4 column 2? given that r4c3, r9c2, r9c3 all can contain 1 and 2 this means r4c2 must be 8.
Yes that is right! Another 1 2 pair in r4c2 means that the puzzle would have two solutions, so that square must be the only other digit possible, an 8!
10:58 Mind blown. Wow. That would NOT have jumped out at me!
I put the above numbers into the on line Sudulo +Solutions site where I normally do Sudoko on my I pad and asked it to rate this puzzle. It said there were multiple answers (20 I think) for this one.This is a good site as u can copy in any sudoko and do it. it will generate the possiblecanadates for each square or u can pencil them in yourself. Would like to hear your comments.
I know this is an old video. But at 1:54, how’d he know that 5 went there. Why couldn’t it also go under the 4
At 5:00 why did you chose the number 4 and 6 to hunt an x wing? That's the very thing I need too learn. Please someone explain me.
Yes, very enjoyable.
This is what I'm talking about, a great logical solve.
A really enjoyable puzzle!
Thank you. C
How do you limit x-wings?
What sudoku program is this? I'd love to use the pencil marks like this, but mine doesn't have them.
May I ask what program, web page, or tool do you use for solving your puzzles? I use a paper form i made up but I like the way your program allows pencil marks and removes a mark when a cell uses a number in an intersecting cell.
With the greatest respect for Simon's Sudoku expertise, which I do not even begin to approach, he seems to have needlessly complicated the solving of this puzzle by introducing overlapping x-wings and other complicated logic. Here is a much simpler and faster solution: At the point where Simon finds himself at the 5:00 mark, I continued first by noting easily that the r1c9 cell can only be 2 or a 9. This quickly reduces the whole column 9 to cells containing no more than 2 numbers, and does the same for the lower left grid. At that point, I noticed a 3 x-wing in rows 3, 4 and columns 4, 8 (the 3 in r3C6 can be eliminated, since it would force two 3's in row 4). By eliminating the 3 from r3c6, it forces a 9 there, which in quick form solves the entire top 3 rows, and the rest of the puzzle in quick order. Simon gets to this same x-wing, but only at 14:45, after a long and complicated route with a pair of overlapping x-wings.
One other point: At the 11:00 mark, Simon again uses complicated logic instead of a simpler method to prove that r2c3 is an 8. Since there already is a 7-9 in r7c3, and row 3 already has an 8, we have a 7-9 pair and that forces an 8 in r2c3.
Where the books of author oku avaliable? Pl, inform as I want to buy
definitely mind-opening for me. I got to the position 5:00 quite easily as i've solved many sudokus before, however got stuck then. Those x-Wings patterns will indeed improve my game. Thumbs up
Thanks, what program are you using? I'm still doing the pencil eraser thing! Is it possible to enter your own numbers? Start with a blank and enter your own puzzle?
Nice, formalizing techniques like that makes solving easier :) Nice video
15:07 With the x swing of 3 u could have put 6 in 5th column at second row
Thanks, that 34 in the middle square was cool
Thanks, I am starting to follow your technique by NOT filling in all possibles, and focus sing on pairs
I'm surprised you move away from Snyder notation as quickly as you do in this case. I solved this on paper quite quickly without (consciously) identifying an x-wing, just by following snyder notation, and then identifying a couple doubles and pairs. Overall it took relatively few pencil marks to solve (good, because I only had a pen, lol.)
I am new to this and I have a question, at 9:40 you pencil marked 1 -1 on the boxes, but how can you be so sure that the 9 you added at 9:47 is correct? Column 2 and 3 didn't have any 9 in them so one of those 1-1 could also contain 9. I can't follow the logic
The reason is that you need to focus on the possible numbers that could possibly go in to r9c4. Because of the triple on 4/6/7 already in row 9 this square is very limited indeed. In fact, it can only be a 1 or a 9 due to the other numbers in its row/column/3x3 block. So once I identify that there are the pencil-marked 1s you mention in either r9c2 or r9c3, I KNOW there cannot be a 1 in r9c4 anymore. So it must be a 9!
@@CrackingTheCryptic Thank you very much for responding! I get it now! :)
Sadly, I am yet to spot my first x-wing. This might remind me to actually look.
Me too:(
6:30 I don't get how he put the 2 at 6:30 :/ This is probably too advanced for me and he's clearly very good at recognizing the patterns, but I feel like he does too much steps in his head if like he said he's trying to make a "tutorial" out of this. But i get it that it must be boring if he went more basic for all of you who are experience at this. Thanks a lot anyway, I'll know where to look once I get better at this ;)
Pretty puzzle though I would only put it at 'moderate difficulty'. Didn't need X-wings to solve, just simple scanning of large boxes, rows & columns, together with identifying doubles & triples. Or am I missing the point? I enjoyed the presentation style.
Great!
Agreed it's a great puzzle but you only need to spot the x-wing on 3s and the position of the 8 in the first box in order to be able to solve it. I wonder how long it took for the author to compile the puzzle.
Hi, I realy enjoyed this but I would ask that you cut down on the very basic observations early on to allow you a little more time to explain the more advanced logic that comes into play later. Thanks once again as I am slowly grasping how to search for the x wing . An in depth explanation of it's use and why other notations can then be ignored. Thank You,
What the hell is an xwing...
lmgtfy.com/?q=sudoku+x+wing&s=l
اتابع طريقة حل هذه الالغاز بطرق مختلفة
following
16:31, 2 into r4c5 how?
In the central 3x3 block at that point there are two cells containing pencil-marked 3 and 4 ie there is a pair. This pair interacts with the 2 I've just found in r5c9 and forces the 2 into r4c5.
@@CrackingTheCryptic true, guess i have no attention span and forgot about the naked pair already
Thanks for asking. I missed the naked pair too.
Cute, Pencilmarks *_*
0:49 start of content
solved
well, that was not helpful
Do you actually use notation "pencil marks" when you solve sudokus or is this simply for your audience to understand your thinking?
I've cracked thousands of them over the years (including yours on pause before you went through your explanation) without using a single notation for available numbers.
I simply keep all deduced number combos in my head as I get to them (like your 7/9 and 1/2 in the BL grid) as I go along and simply apply that as other limiting number options interact (like the 9/8/7 combo in TL grid) and then fill each correct number in as it occurs.
I know its not cheating to write down possible number combos, etc. , but it somehow feels unsporting.
Also, I find my methodology to be a much more streamlined process without all of that clutter trying to help me. :)
Lastly, this x-wing concept is something I've come across as a natural recourse of repeatedly crunching numbers in combination over the years but I didn't know that it actually has a name or that it is a commonly recognized system of solution. I only knew that it worked, which was good enough for me... :)
I do more or less the same thing but copy the numbers into a fairly large grid and write the missing ones outside, gradually resolving the position with locked pairs (4/7) etc, like yourself. But I think this puzzle needed a bit extra. What really amazes me, though, is the fact that this is hand-written.
the jumping around of your highlighter... distracting as all get out.. cannot concentrate. I do easy sudoku and if there is numeral 4 or whatever in or on one level I jump down or up to the other level and keep doing that. This will fill in some few squares to get me started. Honestly sir this 'instructional' is ideal fiddling about for the self when alone … it's not at all, in the remotest sense a teaching tool …. it's not a " HOW TO" in this state of shall we say clutter. A lot of it can be slimmed down at time of editing...
Sorry but I am finding this very hard you are going so fast
Please stop shaking the cursor about when asking us to look at things my eyes automatically follow the movement and can't focus on the problem
I thought I was the only one who found the shaking very distracting
Your solution is incorrect. Your first mistake was in placing the 4 in the center of the left-center square.. The left center square should (right to left and top to bottom) is 741,523,986
With respect, the 4 you mention is given at the start so I don't think it can be in the wrong place :). The numbers in grey are the starting numbers; the numbers in black are entries I make during my solve.
not clear, too fast, pretty useless as tutorial
Patiently do difficult puzzles for another month, then come back to this. Repeat as necessary until it makes sense. It will. I probably would not have understood this a month ago. Hang in there iwona.
works good for me
He did go fast, but it was still worthwhile to watch this video just to see an expert in action. Wonderful stuff.
Something to aspire to
It's taken me about 7 years of doing puzzles daily.....
Dear Iwona, if there is one thing Simon CANNOT be accused of, and that is that he goes too fast!
If I want careful detailed explanations, I always know I will get them here!
Perhaps, my friend, the problem lies in the fact that Simon mostly does hard/fiendish and above.
Therefore, there is a learning curve before anyone is ready for this site!
Simon has to constantly strike the balance between being helpful and being boring!!
Personally, I find he holds that balance very well.
Thank you. Chris
you are far too hard to understand