X-Wings and the Rectangle Rule for Solving Medium to Hard Sudoku Puzzles

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Lesson #10: X-wing patterns appear often and can be used as a Sudoku solving strategy to eliminate candidates. This quick Sudoku lesson explains how to recognize the X-wing pattern, also known as the rectangle rule, and how to use it as a strategy to solve Medium and Hard level Sudoku puzzles. Keep practicing, and learn something new every day!
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Опубликовано:

23 сен 2024

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Комментарии : 109

@hilaydt Год назад

I've watched many other videos and read tutorials on how to do X wings and I never understood until I watched your breakdown. Thanks so much for the clear explanation!

@majaber1 Год назад

me too

@rameshramasamy21 Год назад

Me too

@leemelbourne-weaver4337 Год назад

ME too

@soniaperezcaceres3935 10 месяцев назад

Same!!!!

@RandomThingsEn 7 месяцев назад

SAME! the other tutorials didn't really mention the rows part

@rameshramasamy21 Год назад

Thank you for clearly explaning. I was not able to resolve a sudoku and didn't sleep for 5 days. Your video rescued me.

@StephenRahrig 6 месяцев назад

Why are you calling it a 2 x 2

@oingomoingo7411 18 дней назад

ya i also dont get it

@florian2442 13 дней назад

My guess is that in Sudoku an "A x B" rectangle is defined where A and B represent the amount that a candidate number shows up, and not how many spaces they are apart. For example a "2x1" rectangle is any rectangle that connects 2 candidate numbers on their row/columb no matter how far apart they are

@flynn1a Год назад

I have watched several x wing videos and couldn’t get the gist of what they were saying. But you made it so simple and so obvious! Thank you!!!!

@jballenger9240 5 месяцев назад

The clearest explanation I’ve heard of the X-wing. Thank you m

@mattnorton3285 Год назад

Apologies if I'm missing an obvious implication, but for the part of the video from 1:26 to 1:34, why must the 2 in column 7 be the correct one? Why couldn't the 2 in column 8 be correct? (and same question for the 2 in column 9 in row C)

@fire285 Год назад

Hey, the square is the only option for these numbers. We know 2 must be present in column 4 and 7 and that all other options in column 4 and 7 cannot hold a two. As a generalized rule, if a square exists where either a row or column requires a number to be in the square then both the row and column require the numbers to be in the square.

@love4music25 7 месяцев назад

can you expand further? @@fire285 I still didnot get it

@hebum 4 месяца назад

I was wondering about the same thing but if you look at the column 7 , 2 can be placed in only in the A or C rows for that column so we wouldn't even mark 8A or 9C as possibilities 🤦‍♂

@kallisto9680 2 месяца назад

@@hebumThanks for helping. Now I understand ☺️.

@hebum 2 месяца назад

@@kallisto9680 👍

@SmartHobbies 2 года назад

Great straightforward explanation of X-wings. I always found it interesting that 2x2 are called “wings” where 3x3, 4x4, etc. all are “fish”. I look forward to watching more of your content.

@LearnSomethingNewEveryDay 2 года назад

Thanks Smart Hobbies.....yes it is interesting how these are called exotic fish names.....thanks for your support, I appreciate it! Good luck with your channel, it looks interesting....I just subbed!

@rajeshwarichauhan4257 Год назад

I had been trying to understand this pattern from many videos ...but u explained it so clearly...i got it in a minute..❤🌻

@LearnSomethingNewEveryDay Год назад

Glad to hear that, thanks for the comment!

@r.mcd2921 5 месяцев назад

Thank you - this was the first explanation that made sense to me.

@JonJacks Год назад

Okay wow! I've seen the X wing so many times and never thought there was a strategy. THANK. YOU.

@pepitocovid-91 7 дней назад

THANK YOU SO MUCH FOR THE EXPLANATION, THIS WILL HELP ME SO MUCH

@179Kreator 5 месяцев назад

Hello, I applied it in a an expert sudoku and it didn’t work

@kalpanasarkar9331 2 года назад

Best explanation of x wing I've come across so far

@robertvolm3609 Год назад

So, does this mean that a "X" is always a 3 square by 4 square grid? Can it be 4 squares by 5 squares? Or anything different?

@TunioS19 Год назад

Sorry but I think THIS IS NOT X-wings technique. At example 1, in column 7, there only 2 possibilities for number 2 (A7 & C7) and they also in the same Square 3. Therefore in Square 3, we can eliminate the others number 2 at A8 & C9. There's no need to use 2 number 2 in column 4 as she called this X-wings. (The similiar thing at example 2...). I think she should use other examples for this technique.

@juliafullbusterdododotanmh6837 3 месяца назад

I agree

@kevinklise7036 2 года назад

A good explanation. However, I need to ask for a couple points of clarification. If the particular number being used as the four corners of the rectangle (in this video, it was a "2"), then all the other 2's in that row can be eliminated. Does that include the 2's that are ONLY OUTSIDE the rectangle? Or can it include the 2's (if any) BETWEEN the four corners of the rectangle?

@eugenetswong 4 месяца назад

Yes, between and outside. I remember it this way: it doesn't matter how you find the rectangle; eliminate all of them in the columns and rows, except the 4 corners.

@david1benson2jonas Месяц назад

Great video, super easy to understand. Thank you!

@timothymarchant Год назад

so what happens with the annotated number outside the rectangle but in the same box but it's in the middle/ For example if Cell B9 had a 2 candidate as well would that justify removing that candidate?

@PhillipFlop3327 6 месяцев назад

I was wondering the same thing

@albythegreat4648 11 месяцев назад

Still unsure if that's really a fact you can eliminate the other numbers in the same group or not. Couldn't the 2 still possibly be in the other 2 spots?

@eyefeelpineal4079 9 месяцев назад

Yeah that's what I'm struggling with

@sudharshank8256 4 месяца назад

This method doesn't work. I wonder how this video got so many positive comments

@ancho-31337 2 месяца назад

No, because those are the only sets of 2s in columns 4 and 7.

@NightSovereign 7 месяцев назад

what does 2x2 stand for? And why is the rectangle 4x3 is called so?

@BillSmith-bd1yv 7 месяцев назад

Sorry, I don't understand why we would call an area of 4 squares by 3 a "2x2 rectangle" and if it really was 2x2 then wouldn't it be a square? Asking for clarification because I can see lots of potential candidate configurations, but they can't all be usable. Thanks in advance.

@claudegiguere8731 Год назад

straight to the point and excellent explanations 👍 Thanks a lot !!!

@lindac6147 2 года назад

I’m confused . You state when referring to the first example ( ~3:00) with “2” that they are identified to be part of an x wing if the candidate only appears twice. However “2” appears three times on row A?

@groslou9997 2 года назад

You have to think in columb

@groslou9997 2 года назад

Column 7

@diramaking4302 Год назад

@@groslou9997 Thanks bro. This is what was confusing me for so long. I am quite good at sudoku and I was confused how I am not understanding what everyone is calling a simple technique. I can't believe I was overlooking this... I have been using this for so long without realising it...

@elkabat5205 Год назад

@@groslou9997okay but then I don't need the X-wing right? If I can see that no other 2 can appear in column 7 then its obvious that rows 1 or 3 must have a 2. Am I missing something?

@divermike8943 6 месяцев назад

Why do you say it is a 2x2 retangle? The first example with the 4s is three rows by four columns. So is the second example with the 2s. Does the size of the retangle even matter?

@DiederdirkDusty 3 месяца назад

The size doesn't matter, only that 2 colomns/rows contain 4 cells where a candidate can go and form a x-pattern.

@garondes1 Год назад

I just don’t get it, there are other numbers that repeat also like the 6 7 and 8, why don’t they form an X wing? why choose the 2 in particular?

@muhammadzakyyahya1625 Год назад

I still don't understand the first example..

@abhishekshandilya273 2 месяца назад

Me too were you able to figure it out? I mean lets assume the 2is in A4 although this eliminates 2 from row A yet still the 2 can still be in C7 or C9. How can C9 as a candidate for 2 be eliminated? Same problem with A8 if we assume C4 to be 2

@martinaperez9594 Год назад

Such an useful trick! I'll implement it, thanks!

@faisalrezhaRakhman Год назад

Easy to understand, thanks alot.

@dras227 2 года назад

how it is an X pattern? if 2 in A4 is true, then both 2's in C7 and C9 can be true

@MacXpert74 Год назад

They can't because you need to look at the columns in this case. In both column 4 and column 7 the ONLY 2's are in row A & C, therefore forming a X-wing, this then allows to eliminate any other 2's in those rows. Because if you would place the 2 in C9, you can't place any 2's anywhere in column C7, which would make the Sudoku invalid.

@Brathadoir 21 день назад

Best explanation ever.

@blainenewton7188 22 дня назад

Excellent explanation.

@aubreymaichi4600 Год назад

omg finally a vid that's easy for me to understand😢

@tomcat1184 27 дней назад

wow thank you for this !!!!

@ruatoomey9107 11 месяцев назад

Top class, thank you

@royalbloodedmutt 4 месяца назад

Finally an explanation that makes sense!!! Bless you.

@scorbett4370 2 года назад

Is this rectangle referred to as a 2 by 2 because it involves 2 Blocks AND 2 Rows AND 2 Columns? Thank you for the video.

@Omoplata183 3 месяца назад

I finally get it, thank you for this!!

@kskaliprasadkotagal6468 2 года назад

Thanks for sharing this idea of elimination

@believeinaction 2 года назад

Love from India 🤩🤩🤩🔥🔥

@yennisutedjo4173 Год назад

Nice explanation

@sureshpreeth День назад

Will u solve my puzzle which I was stuck, all repeated numbers can't be filled, will u

@danielkirby3079 8 месяцев назад

I’m sorry, I listened to the video several times and I never understood where you explained which was the correct 2. One of the comments was between 1:26-1:34 of your video but I didn’t catch it. I did hear where you spoke of eliminating other 2’s in actual rows but couldn’t discern which 2 you picked in the x-wing. Most of the comments seem to be happy with your explanation so I am sure it’s just my ADD or lack of understanding. Could you please explain how you picked the correct 2 in the x-wing and not how you eliminated the other 2’s?

@hieutv.thebattlecats Год назад

very nice

@florinprisecaru4809 3 месяца назад

Why did you eliminate those 2 ? Why should we keep 2 from A7 and not from A8 and C9 column? For me has no logic. Sorry It would be al right if we eliminated all 2 from column 4 and 7. But in this situation 2 can be in A7 and A 8 50 % 50% and the same C and C9.

@oksanaball6494 6 месяцев назад

Why did you pick number 2 and not 6,7 or 8? Number 4 and not 5, 6, 7 or 8?

@kenjohnson4645 Год назад

Would if be possible to get the name or link of the Sudoku program that you use in your tutorials as I wanted a program that would allow the user to take advantage of or have the ability to use a "Red X" or similar markings.

@kennethwoodby4528 2 года назад

what does it mean when we say that a cell cant see eachother

@LearnSomethingNewEveryDay 2 года назад

these are also called "peer" cells, they are either in the same block, row, or column, then they "see" each other. Hope that helps.

@robertnutt4944 2 года назад

Hi, how does this work in a 16 x 16 Sudoku? Any different?

@SmedleyAndrea 9 часов назад

431 Kuhn Inlet

@kaneshoots 8 месяцев назад

I still can't understand why you choose the 2's in the beginning as there are also, 6s 7s 8s

@aninterviewwith...1702 5 месяцев назад

I'll have to come back to this one. I still don't get it.

@Fenar_ 6 месяцев назад

Can someone explain why the twos in column 8 and 9 wouldn't be a possibility?

@RusNad 6 месяцев назад

Because column 7's twos have to be in the top right box, that already eliminates the twos in column 8 and 9

@RusNad 6 месяцев назад

But I think even if they were across different boxes, the x-wing means that if A8 was two, then C4 and C7 would both have to be two, which is impossible.

@ramanaross 4 месяца назад

Sorry, incorrect. This is NOT and X Wing pattern. X Wing logic requires the four setup numbers to be in four different blocks. Your analysis is false because ... if the 2 in Block 2 Row 1 is true, then either of the 2's in Block 3 Row 3 can be true. Likewise, if the 2 in Block 2 Row 3 is true, then either of 2's in Block 3 Row 1 can be true. No eliminations can be made. What you have shown is a setup for a possible Unique Rectangle analysis which requires the four numbers to be in only two blocks.