The Powerful XY-Wing! / Sudoku Tutorial #23
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- Опубликовано: 22 авг 2024
- Explanation and demonstration of the XY-Wing Pattern in Sudoku. Three Bi-Value Cells connected by an Alternate Inference Chain, in an easily-identifiable configuration. Allows for the elimination of False Candidates. Includes many examples.
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You give the best explanation of anybody online for XY-Wings and XYZ-Wings. You must have been a teacher at one time.
Thank you for your comment. No, I was never a "teacher" per se. I simply explain all this stuff, the best way I can.
If you enjoyed this Video, please don't forget to click the SUBSCRIBE button, and the Thumbs Up Icon. It will really help me out. Thank you!
I couldn't understand why you started the course with the rather complex AIC concept until you brought in the 'easier' strategies and demonstrated that they're just specific forms of an alternative inference - this being a prime example (XY wing lesson)
Revelatory.
Thx so much for putting these together. Clearly an act of love, and obviously took a lot of work. You da Man
There is method to my madness. :-))
you all probably dont care at all but does anybody know a trick to log back into an instagram account?
I somehow lost the account password. I appreciate any help you can give me.
@Mathias Steven instablaster ;)
@Arturo Steven Thanks for your reply. I found the site on google and I'm trying it out atm.
Seems to take a while so I will reply here later with my results.
@Arturo Steven it did the trick and I actually got access to my account again. I am so happy!
Thank you so much, you saved my account!
The best basic and advanced Sudoku tutorial on RUclips ,hail swami
thank you so much for these videos. I've been searching for good sudoku video tutorials that went further than being about X-Wings.
Thanks for your appreciation.
@@SudokuSwami Will you please start including info on the piano pieces in your intros? It'd be greatly appreciated!
In many of my Videos, (but not on the earliest ones), you can find the names of the piano pieces you hear, on the logo screen, at the end. But I see it is not listed on this Lesson (#23). What you hear is Chopin's Etude Opus 25 #21 in Gb Major. BTW: I almost did not see your message because you replied to an older message from somebody else. Next time you want to tell me something, please start a new thread. Thank you.
The accumulated knowledge is paying off now! BUG was a breather and XY-Wing only a shortcut to AIC type I. Going through these lessons again (with the benefit of the acquired background) is a real delight!
Sudoku people you don't know what you're missing by not "studying" the Sudoku Swami Tutorials:))!
Thanks for your enthusiasm and for your nice endorsement.
Can’t agree with you more.
thank you for using so many examples. my English is not perfect so even after the long explanation I was still struggling to get it, but once you put into practice over and over again I saw what you meant. thanks!!
Your English is fine. Thanks for your comment. I have had other people say that I show TOO MANY examples! Ha ha. Good luck, and please let me know if you have any questions. :-))
The *X-wing* is actually a true wing, at least in science fiction❗It was used, for instance in *X-wing starfighters* (Star wars).
However, I agree with you that an *X-wing* should be classified as a _"fish pattern,"_ by definition.
Please visit sudokuswami.com for an Outline of the Complete Course and news about upcoming Videos! Thanks.
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This is really powerful when you spot one.
Sudoku Swami, have you ever considered producing a book that is full of puzzles,. such as you take us through in this video, that test the students ability to identify XY wings and other advanced sudoku strategies? I have searched for something like this and not found anything.
One challenge with all of these excellent logic techniques is how to name them (people seem to have come up with some real doozies). The next challenge is standardizing the nomenclature. When I started watching this video I started thinking that this is actually a Y-Wing you are describing. www.sudokuwiki.org/Y_Wing_Strategy
After doing some digging, it appears that the X-Y Wing and Y-Wing are the same thing. (Please correct me if I am wrong).
I originally learned this technique from someone who described it as a "bent triple" which makes more sense as a descriptor to me than any of these algebraic terms. The idea of the bent triple description is that if these three cells were in one column or row, you would have a triple, but instead, one cell is offset, or "bent", (as you mention in the video) allowing potential removal of the common pincer digit from any cell that sees both pincer cells. Instead of getting too caught up in complicated AIC logic, I find it easier to consider that no matter which digit is true in the pivot cell, the common digit in the pincers will be true in once pincer. This instantly tells you that the common pincer digit necessitates removal of that digit from any cell that sees both pincer cells, without building a complicated five-link AIC. I find this an easier way to view the (X)Y-Wing.
Once again, thank you for your thoroughness and for making these instructional videos available. I have learned a tremendous amount for you.
XY signifies that there are two Candidates in each Cell of the Wing. Y loosely refers to the shape of the configuration. Bent Triple is a perfectly fine way to think of it. I used the AIC perspective as proof of its logic. It makes no difference how you think of it, as long as you understand it. "A rose by any other name would smell as sweet." --William Shakespeare
I agree with Brian F.
1) BENT TRIPLE is a much more meaningful name.
2) Another meaningful name is Y-WING, which works well when compared with the term X-WING. Both terms refer to the shape of the configuration and therefore are easy to understand and remember, although an Y-WING is a true wing, composed of Bi-value cells (BVCs), while an X-WING is neither wing-shaped nor composed of BVCs. Notice, however, that the shape of an XY-WING resembles more closely a V, rather than a Y.
3) Hence, another meaningful name would be V-WING, which unfortunately nobody uses. It also refers to the shape of the wing, of course.
4) On the opposite, XY-WING is somewhat misleading. It is supposed to refer to the fact that each cell in the wing is a BVC, but it might be interpreted as a term denoting a chain which contains only two different candidates (X and Y), rather than three (A, B, and C). Because of that ambiguity, the term XY-WING is also difficult to remember.
I also agree that standardizing the nomenclature is necessary. Maybe a discussion can be started on Wikipedia.
@@SudokuSwami Of course, the term XY-WING works well when compared to the term XYZ-WING, because both terms refer to the number of candidates contained in the pivot cell. So, I understand the reason why you decided to adopt this ambiguous (but consistent) terminology. However, I would rather use alternative names for both techniques.
For instance, consider that the concept of "BENT TRIPLE" applies to both XY-WINGs and XYZ-WINGs. Hence, XYZ-WINGs might be simply called BENT TRIPLEs with tri-value pivot.
The same is true for the concept of "Y-WING" (or "V-WING"), because it refers to the shape of the configuration, and both XY-WINGs and XYZ-WINGs have the shape of a letter Y (or V).
Was waiting for this video for a long time. You are the best. Thank a lot.
Thanks for sticking with me.....
The logic here is actually bit more simple than Sudoku Swami lets on, although he does a fantastic job capturing the subtlety of it.
Because r3c5 can only be a 1 or a 3, it's impossible for r1c6 to be a 1 AND r3c9 x to be a 3, for then r3c5 would be an empty cell. And since the only other candidates in the those cells are both 9s, at least one of them must be a 9. That means you can eliminate all 9s from the top row of the northeast block, because any 9s there would eliminate both of the nines mentioned previously, yielding the empty cell in r3c5.
OR you could look at it this way: r1c6 can only be a 1 or a 9. If it's a 9, then all the 9s in the top row of the block to the right are eliminated. If it's a 1, then r3c5=3, r3c9=9, eliminating all other 9s in the northwest block, which again includes the three eliminated 9s from the first scenario. Either way, those nines don't exist, so we can rule them out.
I like to call this pattern "Jocko's Triangle" in his honor : )
I enjoyed videos 23 and 24; they were very thorough and well produced. Now, I am eager to start watching the entire series from the beginning. Is the Sudoku app you use in the videos available to the public?
16:50 there is another xy-wing of 3-4-7 in r2c17 and r3c2 to eliminate a 3 in r2c2.
You are correct! If we were solving this puzzle, we certainly would have used that. These examples are for demonstration purposes only. But you have a good eye to have seen that. Well done.
I think a better way to see and find the kill zone is this: if one candidate is true, it leads to a contradiction in the XY Wing. It is better for beginners, of course.
First to comment having watched the video.
Very well explained, these things can often take me a while to spot in puzzles (it took me about 2 minutes for each of your examples just to spot them) though still easier than hidden subsets. The first example I spotted a different XY wing to yours but yours had more elimiations than mine.
Stick with it. You'll get it. Practice makes perfect. :-))
I tried to use x wing but doesn't work so I think I have to use x y wing but I don't understand it yet.can someone simplify it.thank u
Mostafa, this Video is about XY-Wing. Not X-Wing. Both techniques will ALWAYS work, if you identify them correctly. Please watch the Videos again. I am sure you will understand them if you listen carefully to what I am saying. :-))
AB has to be always a pivot cell. Or Can AC or BC acts as pivot cell? Amazing, you come up with great technique of strong and weak link to solve sodoku. Thanks for sharing your knowledge. It makes more fun and interesting to solve sodoku .
The letters ABC are interchangeable. The key is that whatever two Candidates are in the Pivot Cell, then the third Candidate must be in BOTH Pincer Cells. So if the Pivot is AB, then it will look like this: AC --- AB --- BC. And if the Pivot is AC, it will look like this: AB --- AC --- CB
@@SudokuSwami How to make difference or make the right choice for choosin the pivot cell ?
This is a simple but very powerful technique.
Are you making any more tutorial videos? I see that your last one was five months ago.
I hope to resume video production sometime later this year (2020), although it is uncertain at this time. Thank you for your interest.
I do not seem able to find videos 24 onwards. Do they exist? Thanks.
Thank you for the video. Well explainet, au usual ;-)
Hello Mirek, Thanks for your comment and for your continued support.
I like and solve sudoku for many yars, but you show me technics I even didn't know that they exist... hahaha
Maby in your short video you could give some tips how to look for AIC. Thanks for you now I know that something like this exist and helps to solve some very difficult puzzles but I realy don't know how to looks for them!
Thank you for your course!
I appreciate your remarks and your interest in my Course. I just need 999,999 more Subscribers like YOU.
Videos #33 thru #44 will cover AIC's and Loops in great detail. These very important and powerful Chains are not always easy to find and construct. It takes a lot of practice. But I will give you as many tips as I can, in those Lessons, to help you look for them and build them.
So it is a long time to wait for this lessons ;-) but I will becouse I'm sure it is worth waiting. Today I watch this XY-wing and find this in some puzzles I try to solve. It was great!
I believe that the same would be with AIC's :-D
Step by step, we'll get there. One Lesson at a time, my friend. :-))
So XYZ wing...all 3 cells need to be looking at the cell you eliminate while the XY wing needs only see 2 of the cells.
Dear SudokuSwami:
At 13:00 in your video there is another AB (1,6) in Row 6, Column 2 which we can use to proceed with your example.
Hello. Thank you for your interest. The Cell R6C2 containing 1 & 6, at the 13:00 mark of this Video, does not connect to any other Cell to form an XY-Wing. Please try to focus on what I am explaining. We are NOT "solving" these puzzles in the examples. They are meant for demonstration purposes only. Good luck!
Thank you for your clarification.
:-)) I hope you will Subscribe to my Channel. Many more Tutorials are coming.
🌹🔥
These are suuuuuuuuuuuper hard to spot. The difficulty tier I moved up to in the app I use introduces XY wings, XYZ wings, WXYZ wings, hidden unique rectangles, avoidable rectangles, swordfish, finned swordfish, and sashimi swordfish. I've been trying to learn how to spot the specific environment in which XY wings are likely to occur. I thought the general rule of thumb is that pivot cells tend to be in blocks that have a lot of bivalue cells and a lot of conjugate pairs, but some of the examples shown here go against that rule. The 3-block version of the XY wing is especially difficult to see. I have wondered if rows and columns that house naked triples or naked pairs are less likely to house pivot cells, but again some examples here disprove that too. I'm completely at a loss of how to determine which bivalues cannot possibly serve as pivot cells without simple trial and error. Ugh...
I think you are limiting yourself by looking for circumstances, instead of looking for the three BVC's themselves. All you need is/are three Cells, AC-AB-BC, such that the AB (pivot) can see both the AC and the BC. But even when you find this setup, there is no guarantee that there will be an available elimination.
Namaste Swami
So in a couple of the examples of the examples of XY wing tutorial - I saw the pivot & pincer1- were not in the same block as you explained earlier in the rules.
But they were in the same house/ column.
Can you give me a quick explanation of this variation please so I understand?
You are confusing XYZ-Wing with XY-Wing. In an XY-Wing, each Pincer Cell must See the Pivot Cell. This means each Pincer must share a House with the Pivot. It can be a Row, a Column or a Block. Two Houses are required, and it can be any combination, including a Row and a Column, as you can see in three of the examples at 16:00, 17:50, and at 18:20. In an XYZ-Wing one of the Pincers MUST be in the same Block with the Pivot, and any Candidate(s) to be eliminated must see all three Cells.
Thank You.
That is the clarification I needed 👍
If you have a 14 in r1 c1. and 46. In r9 c9 and 16 r4 c4 is this an xy wing?
No. In an XY-Wing the Pivot Cell must see both Pincer Cells. The Cells that you describe do not see each other.
Hi Sudoku Swami. Would you be able to tell me the name of the song you used for this opening? I really liked the song!
It is not a "song." It is Etude Opus 25, #9 in Gb Major, by F. Chopin
@@SudokuSwami Thank you for telling me!
New to sudoku...firsl live example...pls tell me if this is an XY-wing of 186, although I am not sure which would be the pivot. I will name the cells -- R3C1, R9C1, and R7C3.
Yes, you are right. These three Cells form an XY-Wing. The Pivot is R9C1 (with 8 and 6) and the Pincers are the other two Cells. This means either the 1 in R3C1 is True or the 1 in R7C3 is True. This allows you to eliminate the 1 in R2C3. In my examples, I like to show instances of Multiple Candidate Eliminations. So I did not point out your XY-Wing, because it only provides ONE Candidate Elimination. Still, it is great that you saw it. Good job! :-))
@@SudokuSwami Thanks a lot!
OK, I went to the site and learned:
"Current Videos in Progress:
Tutorial #24 XYZ-Wings
Tutorial #25 W-Wings
Random Tips & Tricks Episode 5".
This means that video #23 is currently the last one.
Yes, I am working on those Videos now. The Complete Course is a work in progress. There will be about 25 more Tutorials. And then, if there is enough interest, I will create an Advanced Series of Videos, covering the most complex and difficult-to-find solving techniques. So, based on your question I am assuming you have already mastered all the techniques in Videos #3 thru #23. Correct? The best way to learn my Course is to study the Lessons in strict numerical order. :-))
When the Complete Course is finished, I will continue making Random Tips & Tricks Videos, indefinitely into the future, regardless of whether I do the Advanced Series or not.
Yes absolutely. I religiously studied the videos 1 to 23 although I have skimmed through quickly over Singles, Locked CandidatesType I, Locked Candidates Type II, Pairs and Triplets because these are concepts and techniques I understood before; there was nothing new to me in those videos. I particularly focused and internalized Weak/Strong Links and AICs. After finishing the course I went to Random Tips & Tricks Episode 1 and was able to resolve it using, by and large, the techniques I learned from you. I then watched you solving the puzzle and that did confirm my understanding. Really looking forward to the additional 25 or so videos. FIRST RATE WORK! THANKS A WHALE!
I do hope and pray that you are able to do the Advanced Series! Long live Swami!
I am very happy to hear about your progress. Thank you for your kind words. Good luck!
At 4:30, why BC could not be the pivot cell ?
Because the Pivot Cell must see BOTH Pincer Cells. BC (R3C9) does not see the Cell marked AC (R1C6)
@@SudokuSwami Thank You Very much, that was probably why it couldn't worked some times for me. You're the best.