Tutorial #68 Strong and Weak links and Open Ended Chains, which enable you to remove small numbers.

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Strong and weak links play an important part in eliminating small numbers. The key is to understand the difference between the 2 types of links and understand the sequence of links in a chain. The number of links in a chain can be any odd number e.g. 3,5,7,9,etc and all links in a chain must start and end with a strong link.
OOOOPS!!! sorry I made a mistake at the 3 min point. The weak link in block 6 was meant to be a blue line..not a red line.
techniques and procedures used:
Strong Link , Weak link,,. Definitions., Open ended chains using alternating strong and weak links .If one end is true (correct) the other end is false (incorrect) We don't know which end will be true or false. This is not important as long as you understand that one end will be true and the other end will be false.
/ sudoku-guy-6. .
Thought of the day..... be nice...stay safe!

[@shehum]

Hey Guys. Just spotted something else. There's another little number, 5 in Row 8, making it three 5s in that particular Row - R8C2, R8C5, and R8C8. However, only the little 5 in R8C2 sees both endpoints R3C2 and R8C5! We can therefore only eliminate the little 5 in R8C2 as done by Sudoku Guy in the video! Up to this stage we don't know whether R8C5 or R8C8 is the correct 5. In either case, R8C2 cannot be a 5, and hence can be eliminated! Awesome, Sudoku Guy. Thanks for teaching me this. Can't wait to start seeing these strong and weak links techniques in my subsequent solves!

[@SudokuGuy]

Shehu thanks for your feedback. So glad you found my site,” the most popular site on line to learn sudoku" Please share with others, subscribe and click the bell by the subscribe button. Have fun as you learn step by step how to solve. You can find all of my videos by clicking on the link below. kzbin.info/door/d8JaOdfEWcJOtwG6YayW0w kzbin.info

[@ThredithUndomiel]

I’ve been following your channel for almost 3 years now, and I wanted to thank you for your awesome tutorials. I consider myself good at playing sudoku, but now I’m seeking to learn advanced techniques. I’ll be looking forward to enjoying this new video!

[@SudokuGuy]

Its' great that you wish to advance. Just know that as you reach the more difficult puzzles you will need to know many tricks and techniques many of w'hich I have covered and will cover.

[@becreativewithching-hui7869]

Hi, grandpa Robin! I never heard people using strong and weak links. That's pretty cool. I just love your sense of humor and facial expressions. Creative Math with Ching-Hui 😉🙃😊

[@SudokuGuy]

Hey, thanks, strong and weak links will be important if you wish to learn advanced techniques

[@palemedes965]

Good lesson! I would add to make this clearer that a strong link can also be used as a weak link. That might be helpful to point out and clear up possible questions. Thanks to the Sudoku Swami for his lesson on this, which is very good also.

[@SudokuGuy]

Thanks for sharing! I plan to add that point in another tutorial there was enough to absorb with this tutorial

[@ramdasm9321]

Nowadays I feel confident of solving medium puzzles but hard/tough ones troubles me. I also found that relaxed mind is key to solve. Thank u sir for ur tutorials.

[@SudokuGuy]

Thanks for sharing Ramdas.This tutorial was more for advanced players. So glad you found my site."the most popular site on line to learn sudoku" Please tell others and subscribe and click the bell by the subscribe button. Have fun as you learn step by step how to solve. You can view all of my videos here: kzbin.info/door/d8JaOdfEWcJOtwG6YayW0w

[@stardustbiscuits]

This was my first time joining your premiere .it was fun.i didn't even know you can do so many things in sudoku

[@SudokuGuy]

Hi S that's great that you learnt that there is lots to learn. Hang in there S and master the easier puzzles first. U can do it!. So glad you found my site."the most popular site on line to learn sudoku" Please tell others and subscribe and click the bell by the subscribe button. Have fun as you learn step by step how to solve. You can view all of my videos here: kzbin.info/door/d8JaOdfEWcJOtwG6YayW0w

[@raycicin1794]

Thank you, this was a very clear explanation. I've been having trouble grasping the strong - weak links up to now. 👍🏽

[@SudokuGuy]

Glad it helped Ray. More on these are coming. Watch or them.

[@jamesowusu1794]

I am eagerly looking forward to this amazing tutorial. Congratulations in advance Sudoku Guy.

[@SudokuGuy]

Thanks a lot James. Love to chat with you as well.

[@mikemiles3068]

Great tips‼️I definitely am going to have to play this video several times before it sinks in👍✅🤔

[@SudokuGuy]

Glad it was helpful Mike this is valuable for those who wish to solve advanced puzzles. So glad you found my site."the most popular site on line to learn sudoku" Please tell others and subscribe and click the bell by the subscribe button. Have fun as you learn step by step how to solve. You can view all of my videos here: kzbin.info/door/d8JaOdfEWcJOtwG6YayW0w

[@shehum]

Thank you so much, Sudoku Guy. Couldn't understand these strong/weak links before. Until now. Eagerly awaiting your next video(s) on same. The four little 5s in block 6 however, means that the link(s) between them should be weak and therefore, blue rather than red! Hope I'm correct.

[@SudokuGuy]

Ye you are right see my comment in the description under the video I boobed and didn't see it until too late

[@anonamatron]

This looks really useful, thanks.

[@SudokuGuy]

Glad you think so! So glad you found my site."the most popular site on line to learn sudoku" Please tell others and subscribe and click the bell by the subscribe button. Have fun as you learn step by step how to solve. You can view all of my videos here: kzbin.info/door/d8JaOdfEWcJOtwG6YayW0w

[@timgross8443]

Excellent. I read at least five websites and couldn’t figure out what they were saying. Great job of clearing my confusion

[@SudokuGuy]

Glad it was helpful! You are not the first person to mention this. Thanks. So glad you found my site."the most popular site on line to learn sudoku" Please share with others, subscribe and click the bell by the subscribe button. Have fun as you learn step by step how to solve. kzbin.info/door/d8JaOdfEWcJOtwG6YayW0w sudokuguy.com

[@FranNDR]

Thank you very much for this lesson

[@SudokuGuy]

You are welcome! It's good you understood. Fran hang in there as you learn new techniques.

[@tglrod]

Great video, thanks!

[@SudokuGuy]

Glad you liked it tglrod. So glad you found my site."the most popular site on line to learn sudoku" Please tell others. Have fun as you learn step by step how to solve. You can view all of my videos here: kzbin.info/door/d8JaOdfEWcJOtwG6YayW0w

[@vank5790]

I love your channel it helps so much thank you

[@SudokuGuy]

You are so welcome! So glad you found my site,” the most popular site on line to learn sudoku" Please share with others, subscribe and click the bell by the subscribe button. Have fun as you learn step by step how to solve. You can find all of my videos by clicking on the link below. kzbin.info/door/d8JaOdfEWcJOtwG6YayW0w kzbin.info

[@rg2505]

Mr Robins, you are devising interesting useful Real Techniques to bank on in the wilderness of small numbers near the end of an expert level sudoku puzzle solution. Much better way to give the finish than to make guesstimates in frustration. Big thumps up and thanks again for easy to understand explanations...

[@SudokuGuy]

Wow, thanks r g. You have made my day! So glad you found my site,” the most popular site on line to learn sudoku" Please share with others, subscribe and click the bell by the subscribe button. Have fun as you learn step by step how to solve. You can find all of my videos by clicking on the link below. kzbin.info/door/d8JaOdfEWcJOtwG6YayW0w kzbin.info

[@rg2505]

@@SudokuGuy Sir, already subscribed couple of months ago. Also, tell my friends learned sudoku from scratch from your site. Thanks ..Rajeev Gupta, Mumbai

[@crazyawesomegirl16]

Thank you for your video! It helped me a lot :)

[@SudokuGuy]

Glad to hear that! Vanessa. There are many more tutorials on links coming. So glad you found my site."the most popular site on line to learn sudoku" Please share with others, subscribe and click the bell by the subscribe button. (It’s FREE) Have fun as you learn step by step how to solve. Below is my home page with all the videos listed. kzbin.info/door/d8JaOdfEWcJOtwG6YayW0w kzbin.info www.sudokuguy.com

[@smgille8584]

Hi! I used to play Sudoku when I was a kid and I don't really understand it, tho I feel really happy the when I solved it (by checking every time I put a number 1-9 HAHA)now I enjoy it more because I understand how to answer it thanks to your tutorial, its easy to follow, to understand and will hook u up to play sudoku again and playing is really addicting ♡♡♡ Thank you! Hope you're having a great day.

[@SudokuGuy]

That's great! rocket. Yes it can be addictive. So glad you found my site."the most popular site on line to learn sudoku" Please tell others and subscribe and click the bell by the subscribe button. Have fun as you learn step by step how to solve. You can view all of my videos here: kzbin.info/door/d8JaOdfEWcJOtwG6YayW0w

[@InduDevi-yd6mm]

You are just amazing 😍

[@SudokuGuy]

❤😄😍 Gee thanks! Veer. So glad you found my site,” the most popular site on line to learn sudoku" Please share with others, subscribe and click the bell by the subscribe button. Have fun as you learn step by step how to solve. You can find all of my videos by clicking on the link below. kzbin.info/door/d8JaOdfEWcJOtwG6YayW0w kzbin.info

[@jand147]

Thank you Sudoku guy! This is a hard topic for me to wrap my brain around but I am trying and I am going to watch this video again and maybe some of it will sink in? I don't understand the concept of weak links. I understand what they are but how can they bring you to a correct conclusion? Good job in your explanation of it.

[@SudokuGuy]

Thanks for your comment. I made a mistake and mentioned in the description under the video. The diagonal line in block 6 should be blue not red. Keep watching the next few tutorials and I hope you will understand the difference quickly. You will see this info in the description under the video Look for SHOW MORE Robin

[@kerrybrown1192]

Hello Robin. Thanks for your Tutorials. A note about this one : In column 5 there are 2 Cells shown unresolved. By definition they should be a 'matching pair'. They are notated as 4,5 and 2,5 so the notation is incorrect. As there is already a digit 4 in column 5, starting the chain at the 5 in R8C5 is invalid because the value of that cell is 2. Regards and Stay well.

[@SudokuGuy]

Yes, you are right

[@prabhattomar4587]

Thanks. New thing for beginners. Will help in solving puzzle.

[@SudokuGuy]

Happy to help. So glad you found my site."the most popular site on line to learn sudoku" Please tell others and subscribe and click the bell by the subscribe button. Have fun as you learn step by step how to solve. You can view all of my videos here: kzbin.info/door/d8JaOdfEWcJOtwG6YayW0w

[@mcmurugan4239]

Big Thumbs Up 👍

[@SudokuGuy]

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[@mcmurugan4239]

@@SudokuGuy Welcome!!!

[@stardustbiscuits]

Hey sudoku guy have you ever thought of entering a tournament . you will really do well

[@SudokuGuy]

I'm not fast as I have very poor eyesight. I am pleased that you think this.

[@donnyh3497]

Great video

[@SudokuGuy]

Glad you enjoyed it. Have fun learning more.

[@richardhunter5734]

Wonderful tutorial Sodoku Guy! At 3:26 of the video you show two weak links, for the 3 5s that are in column 5. Shouldn't the link between the two 5s that reside in block 5 really be considered a strong link? I realize that a strong link may be treated as a weak link for inference purposes, but technically is seems like a strong link? Thanks again for your great content!

[@SudokuGuy]

Hi Richard, I talk more about your comment in another tutorial coming. Thanks for your comment. So glad you found my site."the most popular site on line to learn sudoku" Please tell others and subscribe and click the bell by the subscribe button. Have fun as you learn step by step how to solve. You can view all of my videos here: kzbin.info/door/d8JaOdfEWcJOtwG6YayW0w

[@willdavis7525]

Thanks!

[@SudokuGuy]

Thanks Will. And thanks for your support.So glad you found my site."the most popular site online to learn sudoku" Please tell others, subscribe and click the bell by the subscribe button. Have fun as you learn step by step how to solve. You can view all of my videos here: kzbin.info/door/d8JaOdfEWcJOtwG6YayW0w sudokuguy.com

[@danielkoziarski8488]

Missed information: every StrongLink relation can be used as a WeakLink to build a chain. This is because a WeakLink needs TWO (or more) candidate cells in a row/column/box (i.e. in a house).

[@SudokuGuy]

Thanks Daniel for your comment. Yes you are right.

[@ksaiabhiram654]

Sir super channel sudoku Guy 👍👍👍👍👌

[@SudokuGuy]

So glad you found my site."the most popular site on line to learn sudoku" Please tell others and subscribe and click the bell by the subscribe button. Have fun as you learn step by step how to solve. You can view all of my videos here: kzbin.info/door/d8JaOdfEWcJOtwG6YayW0w

[@puzzlechannel4530]

Hello, for a long time we did not see you. Perhaps you are fine, a good return. Thank you for continuing to give you beautiful solutions to the Sudoku puzzle. Greetings, one of the channel's friends and Sudoku fans.

[@SudokuGuy]

Thank you too! Puzzle Channel. More of these are coming soon.

[@benharkness8152]

At 3.08 would that line you drew in the box be a blue line for a weak link?

[@SudokuGuy]

Congratulations you saw a mistake I made. Read below Yes I had the wrong colour.

[@jeffbrunton3291]

you have to alternate strong / weak, correct but you can also use a strong link as a weak link, ie strong - strong - strong still works

[@SudokuGuy]

Yes you are right in both cases. Watch for more on this topic coming soon.

[@h0016911]

Oh. This is new. I’ve never heard of that before. Thank you. But spotting them doesn’t seem to be easy

[@SudokuGuy]

They are but with practice and remembering what to look for you will improve.

[@user-A168]

Good

[@SudokuGuy]

Thanks this is for advanced players. More of this strategy is coming.

[@krishnanr.5677]

Nice insight. Thank you Master, rather than a guy.

[@SudokuGuy]

Glad to help Krishnan Please tell others.

[@DatPug-qw4hm]

Is this the same as the Forcing chain strategy?

[@SudokuGuy]

I'm not sure what you mean by the forcing chain strategy. Sorry.

[@paulmcdevitt2038]

Isn’t what you are finding a skyscraper? Might b a way to spot them but still, what pool are looking for in x-wings and skyscrapers?

[@SudokuGuy]

Hi Paul Strong links or conjugate pairs are the same and are essential for spotting many advanced patterns including the skyscraper, x chain, 2 string kites, X wing, swordfish, turbo fish, finned x wing, empty rectangles and w wings. Some of these I have not covered yet. Please keep watching. Have fun as you learn these and spot them.

[@paulmcdevitt2038]

@@SudokuGuy thanks. Yes, they are hard to spot for sure. So this might be an easier way to do that

[@farisd7057]

X-Chains

[@SudokuGuy]

???? So glad you found my site."the most popular site online to learn sudoku" Please share with others, subscribe and click the bell by the subscribe button. Have fun as you learn step by step how to solve. For a list of videos go here: kzbin.info/door/d8JaOdfEWcJOtwG6YayW0w

[@anishvij5]

If the audio could be louder that would be much appreciated.

[@SudokuGuy]

Turn up your computer sound and see if it helps.

[@SudokuGuy]

Sorry about that I thought it was Ok my end. Try increasing the volume on your device Anish.

[@pascaltorvic6246]

If the 5 in R3C2 is True then the 5 in R3C4 is false, ok, but the 5 in R2C5 can also be false with the 5 in R2C6 being True?

[@SudokuGuy]

Right, thanks for your feedback.

[@pascaltorvic6246]

@@SudokuGuy You're welcome, btw I realy appreciate your lectures that help me so much, keep it up, Sir

[@user-wv7fv4bu1h]

I hope you’re in a pink of health :)

[@SudokuGuy]

I am and I am thankful

[@garysamuel9521]

Block 6 links are all weak links.

[@SudokuGuy]

Right .....see my comment in the description under the video. I ooops! Thanks Gary for pointing this out.

[@TomJones-tx7pb]

The explanation is not accurate - it is backwards. It should go "If one end of the chain is not a 5 then the other end must be a five". That way you can follow a chain of alternating strong and weak links (and the weak link can also be a strong link). In other words, if one end of a any link is a five, the other end cannot be a five, and if the end of a strong link is not a five, the other end must be a five are the facts you use.

[@SudokuGuy]

Thanks for your comment.

[@TomJones-tx7pb]

@@SudokuGuy You are welcome. BTW your video is practically useful. With a chain of strong links, I like to color the boxes alternately red and blue, knowing that anything that sees both colors cannot be the same number. Also, I will note that an X wing is a special case of the alternating strong/weak link structure that you describe.

[@SudokuGuy]

Correct Hang in there Tom.

[@davidwalters313]

I normally enjoy your videos but I am afraid this was poorly explained

[@SudokuGuy]

Thanks David for you comment. There is more coming which I hope will clarify things.

[@h2r205]

Is learning sudoku waste of time and worthless?

[@SudokuGuy]

Absolutely NOT. Sudoku is good for many things your brain, your memory, your logical thinking, enjoyment, satisfaction and leisure activity particularly during the epidemic. 8.5 million views and 60,000 subs says something. So glad you found my site,” the most popular site on line to learn sudoku" I see you have been looking at advanced tutorials. I suggest you start learning by going to the link below which takes you step by step from not knowing anything to the advanced levels Please share with others, subscribe and click the bell by the subscribe button. Have fun as you learn step by step how to solve. You can find all of my videos by clicking on the link below. kzbin.info/door/d8JaOdfEWcJOtwG6YayW0w kzbin.info

[@jonpendragon2066]

This is pointless and make no sense your just drawing lines between numbers taking up space to write numbers

[@ssfjor]

The trick here is to visualize the options: Whenever exists a line or block with two (strong) or more (weak) links, only one of them can have the number. When we analize a chain of links made according the rules, only one of its ends will always be correct. This is always true. Then a cell aligned with both ends cannot contain the number, because in that case the rule will be false and we confirmed it is always true. The lines he draw were to show the situation; in a actual puzzle you don't draw them, only imagine them, and check the possibilities to discard some cell. That's is the difficult part...

[@SudokuGuy]

Thanks ssfior, There is more coming to absorb.

[@nigelm5777]

Clearly from all the comments most folks understood this tutorial and got something out of it. Could it be you that’s missing the point?

[@ssfjor]

@@nigelm5777 It could be. We can't assume to know everything. ☺️

[@jonpendragon2066]

Literly makes 0 sense

[@sandyhafenbrack141]

Literally you need to comment less and study more.

[@SudokuGuy]

Thank you Sandy. May Jon needs to spend more time on easier puzzles.