Conjugate Pairs & How to Use Them! / Sudoku Tutorial #19

[@satorikomeiji3043]

This video is a good summary of what conjugate pairs can do. finding subsets, x wing, swordfish, x-chain and so on. Great!

[@chrisdiner7170]

Been playing sudoku for years but I learned a hell of a lot from your videos.these tutorials are absolutely amazing!

[@karabishopart4153]

Absolutely brilliant! I’ve been so busy looking for Fish patterns and not seeing them and hadn’t thought about starting from a Conjugate pair. This was a great shift in perspective a fantastic review and a few little treats thrown in as well. That’s me off for my daily practice armed with new confidence. Thanks SS!

[@artistaccelerator]

Thank you Swami! Love these!

[@Treyvis97]

Thank you for these videos. They are extremely well put together. I really appreciate the time, effort, and organization behind each one. I'm on #19 right now and plan to continue to the end. Thanks again!

[@SudokuSwami]

Sounds great! Thanks, and good luck.

[@SudokuSwami]

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!

[@jaapjaap1]

Very nice video. It compliments the earlier individual video's by showing HOW you can search knowing these techniques. Whilst watching these earlier video's I was hoping for a video like this. I can now - once I cleaned out the possiblities using the simpler techniques - hunt for use of the more complex techniques by looking specifically at each digit's conjugate pairs and then checking whether any of the techniques (the various x-wings and swordfishes, the three short x-chain variants, empty rectangles, etc) renders something. Or not. I like this structured searching to train my eye, later I hope it beceomes like the simpler techniques which you just 'see'. But am not there yet, and this video will help me get there. So tops again to you Swami!

[@SudokuSwami]

Sounds great. Glad you are making progress!

[@acidutzuabc]

Great course. I followed all the lessons and I will continue for sure. It is captivating.

[@donepstein723]

Good to see these techniques Now trying to put into practice

[@rednectarchris]

at 4:21 you say that locked candidates "like the ones in block 1" can be conjugate pairs - then at 5:13 you say "when you have a conjugate pair within a block the two candidates are ALWAYS going to be on a diagonal". These two statement can't BOTH be true! So what is it? Do conjugate pairs within a block NECESSARILY have to be on a diagonal, or can they share a row or column and be also a locked pair?

[@SudokuSwami]

You cut off my sentence, and misunderstood what I was saying. Locked Pairs ARE Conjugate Pairs. That's why I show them as such at 3:00 and at 4:20.

[@ximorro5247]

This is a very interesting video showing how to search for the techniques we've learnt, in this case guided by the powerful conjugate pairs. One thing is to know the techniques, but a different beast is to find them! So this video showing strategies to search for the patterns is a perfect companion to the ones teaching the techniques themselves, so THANK YOU FOR THAT! Oh, and we also got a sneak preview for W-Wings and remote pairs, he, he. But that X-chain... no idea how to search for useful ones. I don't think it's about starting to make connections and see if something happens by chance...

[@delljames9736]

I am really thrilled with this video course. After only 6 videos in, namely No. 4A Part II, (the one on AIC Type II), I was able to complete one of the worlds hardest Sudoku puzzles (specifically, the one by Finnish mathematician Dr Arto Inkala in 2010). I have been working on it for a month. I wish you were my maths teacher when I was at school. I’m guessing you are or were a professor of maths ...or maybe logic, right? And is that you playing the piano? Having now reached video No. 19, and yes, I really have watched all the previous ones, I and going to pause and start again to consolidate it all. Keep it up!

[@SudokuSwami]

Fantastic. Congratulations. Thanks for the kind words. I hope you will Subscribe and help "spread the word." I am a professional musician/song-writer, with a passion for logic, math, and puzzles. And yes, that's me playing the piano in all the Videos. :-))

[@delljames9736]

Love the music! I am a subscriber and yes, I will spread the word to Sudoku friends as I encounter them - even though that will be rather like the first step of a 12-step programme - i.e. first, I acknowledge I am a Sudoku addict! :)

[@SudokuSwami]

Ha ha. Great. Thanks very much.

[@titushui]

Wow!!! W-Wing and Remote Pairs examples already be taught here!!!

[@SudokuSwami]

W-Wings are covered more fully in Video #25, and Remote Pairs will be fully covered in Video #29, coming soon. :-))

[@titushui]

I had already studied the W-Wing lesson :). When I reviewed again the conjugate pair lesson, I discovered that I overlooked it in the conjugate pairs lesson I had learned several months before .

[@Coyotek4]

25:04 there's a 12th conjugate pair, right? In block 4?

[@SudokuSwami]

Yes. I remember noticing the simple oversight when I was editing that Video, but did not feel that it was important enough to warrant re-filming the entire segment. The point I am making in that example, is that when you see a large number of Conjugate Pairs on a particular Candidate, this indicates a high probability that there may be an X-Chain available. The 12th CP in Block 4 that you pointed out, does not impact the X-Chain I subsequently drew, in any way. So, c’est la vie.

[@pascaltorvic6246]

Does anyone know the great music (intro of the video)? Thx

[@SudokuSwami]

Bourrée from Partita #2 in C minor by J.S. Bach

[@pascaltorvic6246]

@@SudokuSwami Thanks very much swami..

[@SudokuSwami]

In many of the later Videos in the Complete Course, I list the names of the pieces on the End Screen. But I see that on this one I did not.

[@ThatGuy-dj3qr]

Is there any specific terminology used to refer to conjugate pairs that lie in a row or column versus offset conjugate pairs which lie in a box?

[@SudokuSwami]

Not that I am aware of, Brian. If you have only two remaining instances of a particular Candidate in ANY House (i.e., a Row, Column or Block), they are a Conjugate Pair, simply meaning that one of them must be True, and the other must be False.

[@ThatGuy-dj3qr]

Thanks for your quick response @@SudokuSwami. I am writing myself reminder notes on Sudoku strategies, and this requires that I be as specific as possible with nomenclature, because (as you know) things get complicated very quickly when something is put into written word, without aid of a graphic. What started this for me was: I noticed that when I encounter "2-digit" empty rectangles, interesting things begin to happen that don't happen in ERs with three or more digits. These two candidates are themselves are a conjugate pair in the ER block. Then (as you know), ER strategy dictates that one ER line needs to see one digit of a conjugate pair that lies entirely in a row or column (depending on orientation of the ER line). In addition to this, if the second member of that conjugate pair (in the row/column) sees one member of a conjugate (or remote pair) that is in the box adjacent to the ER, then even more interesting things seem to be happening. This strategy (when it occurs) ends up employing three different sets of conjugate pairs, with one pair being in line with each other (sharing the same row or column) and two pairs being offset (where each digit is in a different row and column, but that occupy one block). As I wrote and re-read my own instructions, I began to wonder if there was specific terminology for conjugate pairs that occupied one block, but that were offset from each other, versus a conjugate pair that lie entirely in one column, or one row. The only term I have seen is "pointing pair", but I believe this term refers to a "non-offset" conjugate pair that lie entirely within one block. To delineate, I think I will use the terms "block pair" and "line pair" to describe the different houses that they lie in. But I recognize that even this terminology has limitations, since a conjugate pair in a block can either be offset, or in line with each other.

[@karabishopart4153]

On a diabolical puzzle I used the empty rectangle technique twice and on both occasions the conjugate pair was in a neighbouring block and the candidate B cell reflected back into the empty rectangle and enabled me cannibalise one of the empty rectangle candidates. That move then revealed a naked pair or naked single. Was that just lucky or is that a legitimate and logical move? It seemed pretty cool if it is legitimate!

[@SudokuSwami]

In an Empty Rectangle Pattern, the A and the B Candidates of the Conjugate Pair must lie in two separate Blocks. It cannot work if both Candidates of the Conjugate Pair lie in the same Block.

[@karabishopart4153]

@@SudokuSwami thanks for that I missed that point. Back to the learning

[@fahadalanizi251]

Hello, Is there a relationship between chess and Sudoku, thank you very much.

[@SudokuSwami]

Good question! I would tend to say that there is no real “relationship” between Chess and Sudoku. There are many similarities, but there are many more (and much bigger) differences, in my opinion. For instance: Both games are played on a rectangular grid; Chess 8x8, and Sudoku 9x9. Chess is played with its own specific set of “pieces,” but Sudoku is played with simple numbers. Chess is played versus an opponent (i.e., another human or a computer), and in Sudoku, it is just the player versus the puzzle. In Chess, you can win, lose or draw. In Sudoku, you either solve the puzzle, or you don’t. In Chess, the pieces can be removed from the board, and in Sudoku the candidates can be removed from the grid. But in Chess, it is possible for all the pieces to be removed except for the 2 Kings, whereas in Sudoku, when the puzzle is finished, all 81 cells must contain a digit. Chess and Sudoku each have their own set of Rules, which govern what is allowed, what is not allowed, and they also define the object of the game. And you can study the solving techniques for Sudoku, and you can study the standard Chess openings and all their variants. But the total number of possible outcomes for a Sudoku Puzzle is approximately 5.5 billion, whereas the total number of possible outcomes for a Chess game, is infinite. Both games require problem solving and logic. But Chess requires complex forward-thinking. A successful Chess player must think far in advance, and plan combinations of moves that will force a particular result. But in Sudoku, the player only needs to focus on the one situation he is faced with, at any given moment. It is not necessary to think ahead. In Chess, a series of moves, in order to achieve the desired result, must be performed in a fixed and definite order. Whereas in Sudoku, it is quite often possible to make several moves in a random order to achieve the same result. Both games require imagination. But the greatest Chess players bring the game to the level of an intellectual art form; people such as Paul Morphy or Bobby Fischer. If there are people who play Sudoku like this, I am not aware of it, although it would not surprise me to learn that there ARE such people. It is more likely in Chess, that you will be faced with a situation that you have never encountered before, which will require some very creative thinking, and having to figure out something “brand new,” on the spot. Whereas in Sudoku, it is more likely that you will see recurring patterns, (even though there are millions of them!). Both games are good exercise for the human mind, but they are not alone in this regard. There are many activities in life, that are good for the human mind. Winning a tough game of Chess, or solving a difficult Sudoku puzzle, will both provide a sense of satisfaction and accomplishment. I don’t know if either one is greater than the other. I guess it’s up to each individual person to decide for themselves about that. I think it is probably easier to become a Sudoku Master, than it is to become a Chess Master. But then again, I have read that there are schools around the world today, teaching little children to become Chess Masters. So, who knows? But don’t get me wrong. Sudoku is by no means simple! To be a Sudoku Master requires a great deal of study, dedication and practice, and each puzzle always presents a very interesting, challenging, and enjoyable form of entertainment. I am sure there are many things that I have failed to mention, but this is the best answer I can give you! Thanks for your interest.

[@fahadalanizi251]

Sudoku Swami Great answer, thank you very much.

[@SudokuSwami]

You're welcome. :-))

[@oumaroudia]

Enlightening. The game of GO with its boards (9x9) for beginners and (19x19) for advanced players takes it to another level. The reason I prefer Sudoku or Crosswords etc. is that I compete against myself...and I have less frustration!

[@JonathanJimbo]

Thank you for your series of very informative sudoku videos. Despite already knowing quite a wide range of sudoku techniques (thanks to the enjoy sudoku app I use), I have learned a lot from your videos on empty rectanges (I watched all 45 minutes of it), turbot fish and 2 string kites which were techniques I didn't know. Sure I knew about X chains but I always previously dismissed them as 'impossible to spot', but it never occured to me to look for 3 celled ones. And not only have they been informative but they've translated nicely into helping me make more deductions in puzzles. On the other hand only a small number of these techniques I'm actually able to apply to a sudoku. For example I find hidden subsets extremely hard to find unless I get extremely lucky. And stuff like WXYZ wings (my 'enjoy sudoku app' loves to give me puzzles that require these to solve them) I don't stand a hope of actually being able to find it. In fact I can't even find it even when my app tells me to hunt for one in the current sudoku and I can just end up spending half an hour staring blindly at a sudoku. I'm currently watching the video at the same time as typing this. Thanks for teaching me a new case of W wing. I was previously only familiar with the type D W wing. Back to what I was typing, would you recommend focusing on single digit techniques (especially given my app can highlights all cells of a specific digit) over looking for hidden subsets or various different wings (I mean XY wing XYZ wing or WXYZ wing). And for wings do you start by looking at bivalue cells first or the pivot first or do you look for an ALS (in the case of a WXYZ wing) first and then try and connect it to a bivalue cell. In fact would you even bother looking for WXYZ wings in the first place given that those aren't part of your upcomming videos. Also thank you for your random tips / tricks videos which helped me looked for what sort of stuff you're on the lookout for when actually solving a puzzle. Also I'd be interested in seeing how you'd tackle very very hard puzzles that are far beyond me (I mean the kind that require you to spot complex AIC's that span over multiple digits as well as stuff like ALS-XZ which btw I never even bother looking for). Specifically I mean enjoy sudoku 'maelstrom' difficulty ('devious' is the hardest I've solved with autopencil and highlighting enabled) or one of the sudocue nightmare puzzles (especially the ones from friday-sunday). Anything is allowed (besides getting a computer to solve it for you) including drawing / colouring on the sudoku, evaluating combinations in excel, randomly trying in values and seeing their implications and any common deductions you can make, however you would naturally go about tackling puzzles of that difficulty. And video cuts are allowed too while you look for stuff (although a running timer would give us an idea of how long you had to spend). Whatever you choose to do I'm looking forward to watching your next videos (especially the one on BUG+1 as my 'proof' that I could come up with is a bit shaky, for example is it possible to have a grid just containing bivalue cells where you have hidden singles assuming the puzzle still has either 1-2 solutions and the pencil marks are correct and if not why not?)

[@SudokuSwami]

Hello Jonathan, thank you for your interest and support. Boy, that's quite a lot of questions! I'm working hard on the next couple of videos right now, so I don't have unlimited time to answer. But I will address as many of your issues as I can. I will cover WXYZ-Wings in my Advanced Series. But I agree, they are not that common, and I do not go out of my way to look for them. Your questions about XY-Wings and XYZ-Wings will be answered when I finish those Videos, in the near future. But for now, I try to find them by looking for neighboring Bi-Value Cells with common candidates. For BUG+1, you need to make all the moves you can, and solve as many cells as you can, (including any hidden singles), and then see what you have. It is impossible to know if you have the BUG+1 scenario, until it reveals itself. Good luck!

[@JonathanJimbo]

Sudoku Swami Thank you for your reply / answers. Sorry I've gave you this much questions. I kind of got a bit carried away when writing that.

[@SudokuSwami]

Be sure to visit sudokuswami.com for information about upcoming Videos and an Outline of the Complete Course!

[@thiloweiser-trauma-undhypn8147]

The Link is not valid! ... Where are you now?

[@affable11]

Thank You.

[@SudokuSwami]

You're welcome! :-)) Much more to come.......

[@peterkelley6344]

You keep saying "... and so that MUST be false ... " But you do not state WHY it is false. You leave the viewer to create the reason why it was false.

[@SudokuSwami]

Hello Peter. The Videos in my Complete Course are meant to be viewed in chronological order. Each Tutorial builds on all the the preceding ones. If you understood all the principles in the preceding lessons, you would probably not be asking this question. A Conjugate Pair, by definition, refers to the last two remaining instances of a particular Candidate within a particular House. Only ONE of those two Candidates can be True. There is your "WHY."

[@peterkelley6344]

@@SudokuSwami Trying to be 100% respectful. I fully understand that only ONE candidate can be true. That's the simple part! I guess the problem I having is if I have a conjugate pair, and I look at the Soduko table and I am not seeing any signal from the other known or suspected numbers which is the true. and which is false number of the pair. (off the cuff example) i might have 18 squares of the puzzle that are locked where I can not find that unique number to alter. Yes I look within the subset, the horizontal and the vertical structure of the puzzle. I know there are others who might suggest that a locked puzzle is poorly constructed puzzle. I know there are others who say that taking that 'crap shoot' guess is not good Sudoko process/procedure. My view is that there must be that 'one more evaluation' trick I need to learn to get past those puzzle blocks. I am at the stage where I DO NOT NEED another True/False finder of number sets, What I need is methodology to break through those 18 locked squares to trigger a chain reaction to solve the puzzle. I am open to say that I use an app that presents (and edits) the pencil marks for me.

[@SudokuSwami]

Regarding your first question, please specify a precise time in the Video, and the particular Cells and Candidates you are referring to, and I will explain the "WHY." On a side note, to get the most out of these Lessons, it is best to start at the beginning, watch each Video in chronological order, and do not proceed to the next Video until you full understand the one before.