Join the Smartie Party now 🥳to get EXCLUSIVE reward puzzle packs, ad free content, discord access, and so much more👉👉www.buymeacoffee.com/timberlakeB/membership Timestamps 0:00 Intro 00:32 It’s Solving Time 00:36 XY-Wing Tip #1 03:12 XY-Wing Tip #2 05:26 BONUS Tip 05:52 What To Do When Stuck 06:40 XY-Wing Tip #3 08:50 XY-Wing Tip #4 10:39 XY-Wing Tip #5 13:34 Seeing Effect Of XY-Wings
I found my first Y-wing while centermarking five-digit houses, after cornermarking: 129 in blocks 7 and 9. As usual, when I have nothing else to do, I centermark the grid. Afterwards, I check through each digit. (All 6s were placed by then.) I placed a lone 5 in column 6, but what got me going again was noticing that I had 4s marked that could see a given 4. Fixing that gave me a 18-pair in column 3, which became a two-option Y-wing with two corner cells -- my second and last Y-wing. The rest was cleaning up, with the help of three triples. 0:40 Tip #1: My first Y-wing was a counterexample -- I found it fairly early. I was also reminded of a puzzle several months ago, where I also found an early Y-wing. Watching the video, I thought it was superfluous until right at the end, when I discovered that it did the dirty work of some kind of W-wing that I didn't understand. 9:10 Once I took care of the 4s, that green cell became a 18-cell, giving the 18-pair. (The first Y-wing had already removed the 9.) 10:10 That one was the one I found early on. It has occurred to me that perhaps a "V-wing" might be a better name. 12:20 That was the Y-wing I found considerably later. I decided to apply the 18-pair first. Not that it made a difference.
I agree and I’ll consider your feedback in making future videos. In the meantime, you can learn all about XY-Wings in this tutorial: ruclips.net/video/pE3Z_CvFFME/видео.htmlsi=ZzfskkeJjivvDbFh
He did explain in this video. You have 3 bi-value cells with 3 digits in common, such as AB, BC, and CA. The value of one cell determines that one of the other two cells must contain the 3rd value. If the AB cell is A, then the CA cell is C. But if the AB cell is B, then the BC cell must be C. C can only be in one of those 2 cells. Therefore other cells in common with the BC and AC cells can eliminate the C from among possibilities. Oh, in the initial setup, the AB cell must have the CB and AC cells in common. In the video example, one was same block, another was same column. Rewatch to reinforce this info. Pause video before "reveal" to test your new skill at seeing the 2 different XY-wing formations shown.
Good puzzle, SULPHUR always gives some tough and happy finishing. Filled no's in all cells, got the XY wings, second one 18 is down, and it's, top or down gives same result. Enjoyed, saw vedio nice explanation. Thanks for the puzzle.
That is a great question, Pokey. They work on both. Most of my viewers prefer hand-crafted due to the intended solve path usually being more fun to discover.
I load the puzzles into Sudokumaker, a free desktop app that puzzle creators use. Sudokumaker can then create a link to solve in SudokuPad, which is what you see in the video. SudokuPad allows viewers to solve on either desktop or mobile and also allows coloring, corner marking, and center makring. Hope that helps.
The logic behind the eliminations has to do with the pivot cell. When you plug in both values, you will see that one of the pincers (or “wings”) has to contain a particular candidate. You can then eliminate that candidate from any cell that sees both of the pincers. You can validate it by putting the candidate value into one of the eliminated cells. You will see that the puzzle quickly breaks.
@ Later in the puzzle. I recommend you look for easier strategies at the beginning of your solves. It’s more productive. Then mark any restrictions you may find and bivalue cells. At that point you will likely find the more advanced strategies like XY-Wings. Have you downloaded my free solving guide?
Fun puzzle. Crux is a double X-Y wing facing R7C7. R1C1 as pivot and R3C3, R9C1 as pincers knock out the 1. R9C9 as pivot, R7C7, R1C9 as pincers knock out the 9, leaving only an 8 as a possibility there. After that, it's all pretty routine, nothing advanced needed. Now to watch the explanation.
Well, I found an XY-Wing, but I still needed a quick bit of virtual chaining to continue (83 = row 8 column 3): 83, 54, 56, 81, 78, 19, 35, 98, 68, 57, 73 (XY-Wing, boxes 1 and 7, plus virtual 9 tried in R9C5, quickly leading to a contradiction), 33, 36, 12, 28, 65, 62, 21, 38, 32, 51, 42, 91, 11, 53, 24, 63, 52, 23, 89, 26, 64, 75, 66, 84, 44, 74, 99, 27, 29, 47, 89, 77, 92, 27, 95, 16, 15, 86, 85, 18, 49, 59, 45, 55, 48. Ah, I missed the second XY-Wing. that would have led to the same continuation. A clever puzzle.
Glad you were able to solve it, Julian. Sulphur spent months on the puzzles for our latest puzzle pack, and they are all as clever as this. Would you like to become a Smartie Party member to check the rest of them out?
I appreciate your feedback and look to improve my content with every video. These concepts and strategies can be tough to understand at first. I recommend you check out my XY-Wing Tutorial for a more detailed explanation of how the strategy works: ruclips.net/video/pE3Z_CvFFME/видео.htmlsi=n_sEYjeU3kyGcDxq
Join the Smartie Party now 🥳to get EXCLUSIVE reward puzzle packs, ad free content, discord access, and so much more👉👉www.buymeacoffee.com/timberlakeB/membership
Timestamps
0:00 Intro
00:32 It’s Solving Time
00:36 XY-Wing Tip #1
03:12 XY-Wing Tip #2
05:26 BONUS Tip
05:52 What To Do When Stuck
06:40 XY-Wing Tip #3
08:50 XY-Wing Tip #4
10:39 XY-Wing Tip #5
13:34 Seeing Effect Of XY-Wings
You’re the best at explaining the why that I’ve seen up to date. Thank you.
You are welcome. Thank you for the kind words. 😊
I found my first Y-wing while centermarking five-digit houses, after cornermarking: 129 in blocks 7 and 9. As usual, when I have nothing else to do, I centermark the grid. Afterwards, I check through each digit. (All 6s were placed by then.) I placed a lone 5 in column 6, but what got me going again was noticing that I had 4s marked that could see a given 4. Fixing that gave me a 18-pair in column 3, which became a two-option Y-wing with two corner cells -- my second and last Y-wing. The rest was cleaning up, with the help of three triples.
0:40 Tip #1: My first Y-wing was a counterexample -- I found it fairly early. I was also reminded of a puzzle several months ago, where I also found an early Y-wing. Watching the video, I thought it was superfluous until right at the end, when I discovered that it did the dirty work of some kind of W-wing that I didn't understand.
9:10 Once I took care of the 4s, that green cell became a 18-cell, giving the 18-pair. (The first Y-wing had already removed the 9.)
10:10 That one was the one I found early on. It has occurred to me that perhaps a "V-wing" might be a better name.
12:20 That was the Y-wing I found considerably later. I decided to apply the 18-pair first. Not that it made a difference.
Nice job John. I’m glad you found XY-Wing early. Like you mentioned, that is not too common.
It would be helpful to explain what an XY-wing is before asking us to find one..
I agree and I’ll consider your feedback in making future videos.
In the meantime, you can learn all about XY-Wings in this tutorial: ruclips.net/video/pE3Z_CvFFME/видео.htmlsi=ZzfskkeJjivvDbFh
He did explain in this video. You have 3 bi-value cells with 3 digits in common, such as AB, BC, and CA. The value of one cell determines that one of the other two cells must contain the 3rd value. If the AB cell is A, then the CA cell is C. But if the AB cell is B, then the BC cell must be C. C can only be in one of those 2 cells. Therefore other cells in common with the BC and AC cells can eliminate the C from among possibilities.
Oh, in the initial setup, the AB cell must have the CB and AC cells in common. In the video example, one was same block, another was same column.
Rewatch to reinforce this info. Pause video before "reveal" to test your new skill at seeing the 2 different XY-wing formations shown.
About 8:50 he does exactly this. . .😅
11:42 with your help. It wasn't hard but I couldn't find the xy-wings one more time 😅 thank you! ☺
Any time. 👍🏻
Very nice one. Learning new things with every video.
Glad to hear that. Thank you so much for watching!
Are there any other strategies you want to see?
Good puzzle, SULPHUR always gives some tough and happy finishing. Filled no's in all cells, got the XY wings, second one 18 is down, and it's, top or down gives same result.
Enjoyed, saw vedio nice explanation.
Thanks for the puzzle.
I am glad you enjoyed the puzzle and the video. Thank you for watching.
Nicely explained, Thanks
You are welcome!
I first completed it using mostly SET theory but will redo with the xy wings instead. I am practising both methods.
Nice job, Vanessa. I love that you applied SET to this 🧩.
Do these techniques work on computer generated puzzles or only hand-crafted Sudokus?
That is a great question, Pokey. They work on both. Most of my viewers prefer hand-crafted due to the intended solve path usually being more fun to discover.
What's the app you're using? I downloaded hodoku and it wasn't the same
I load the puzzles into Sudokumaker, a free desktop app that puzzle creators use. Sudokumaker can then create a link to solve in SudokuPad, which is what you see in the video. SudokuPad allows viewers to solve on either desktop or mobile and also allows coloring, corner marking, and center makring. Hope that helps.
When you get to the y box’s what’s the logic behind elimination within them ?
The logic behind the eliminations has to do with the pivot cell. When you plug in both values, you will see that one of the pincers (or “wings”) has to contain a particular candidate. You can then eliminate that candidate from any cell that sees both of the pincers.
You can validate it by putting the candidate value into one of the eliminated cells. You will see that the puzzle quickly breaks.
Thank you for the reply
Would you suggest looking for these early on , or wait till it becomes difficult ?
Andy
@ Later in the puzzle. I recommend you look for easier strategies at the beginning of your solves. It’s more productive. Then mark any restrictions you may find and bivalue cells. At that point you will likely find the more advanced strategies like XY-Wings. Have you downloaded my free solving guide?
@ no I didn’t know you had one
@ 📕Get my FREE Solving Guide that will help you solve over 80% of all Sudoku puzzles to include NYT Hard 👉www.buymeacoffee.com/timberlakeB/e/125822
Fun puzzle. Crux is a double X-Y wing facing R7C7.
R1C1 as pivot and R3C3, R9C1 as pincers knock out the 1.
R9C9 as pivot, R7C7, R1C9 as pincers knock out the 9, leaving only an 8 as a possibility there.
After that, it's all pretty routine, nothing advanced needed. Now to watch the explanation.
You nailed it. Thank you for sharing.
Pair of 18 in column 3 (11:49)
Thank you for pointing that out Roger. That does make the solve go a little easier if you spot that pair.
Well, I found an XY-Wing, but I still needed a quick bit of virtual chaining to continue (83 = row 8 column 3):
83, 54, 56, 81, 78,
19, 35, 98, 68, 57,
73 (XY-Wing, boxes 1 and 7, plus virtual 9 tried in R9C5, quickly leading to a contradiction),
33, 36, 12, 28, 65,
62, 21, 38, 32, 51,
42, 91, 11, 53, 24,
63, 52, 23, 89, 26,
64, 75, 66, 84, 44,
74, 99, 27, 29, 47,
89, 77, 92, 27, 95,
16, 15, 86, 85, 18,
49, 59, 45, 55, 48.
Ah, I missed the second XY-Wing. that would have led to the same continuation. A clever puzzle.
Glad you were able to solve it, Julian. Sulphur spent months on the puzzles for our latest puzzle pack, and they are all as clever as this. Would you like to become a Smartie Party member to check the rest of them out?
You guys are good teachers to learn Sudoku, but you go too fast.
Thank you for the feedback. I am working on slowing the pace a bit, especially with these more extreme puzzles.
This is very basic steps, not avout xy wing. 😡
Thank you for your feedback. What is a tip about XY-Wings that you would like to share?
badly explained too fast
I appreciate your feedback and look to improve my content with every video. These concepts and strategies can be tough to understand at first. I recommend you check out my XY-Wing Tutorial for a more detailed explanation of how the strategy works: ruclips.net/video/pE3Z_CvFFME/видео.htmlsi=n_sEYjeU3kyGcDxq