Thank you for your comment. I really appreciate it. Don't forget about Tutorial #4-A Part 2. :-) At the end of the Complete Course there will be several Videos , focusing on very specific types of AIC's and Loops. So please stay tuned for that. Good luck!

@@SudokuSwami Thank you, Swami. It's all beginning to make sense.

I really appreciate your comment. The best way you can thank me, is to spread the word about this Channel. :-)) Good luck! If you ever have any questions, please let me know.

Yes, understanding how Chains work, is one thing. Constructing them, is yet another. However, I always recommend exhausting all the simpler techniques first, (including the simple Chains, like Turbot Fish, 2-String Kites, Skyscrapers, XY-Wings and W-Wings), before even STARTING to look for the more complex Chains, like long AIC's, Forcing Chains and Continuous Loops, for instance. But when you get to a point in the puzzle where you are "stuck," then you need to look for things that are not immediately obvious. And these are hard to find, for sure. But based on what you are seeing, it can guide you to figure out where to try to begin your long Chains. I will do my best to give you some tips on how to do this, when we get to those Tutorials. Don't worry!

THANKS! SWAMI!

In 90% of the Videos, the titles and composers are displayed at the end. If it is not listed, just ask me.

It is not always immediately apparent, that a Chain, of any kind, exists; which of course, makes it difficult, at first glance, to know where you should start. You have to search, and it takes some practice. But somewhere between Tutorials #27 and #42, (and more than once), I talk about the tell-tale "signs" of the likelihood of a possible Chain. In a nutshell, these signs are large numbers of 1.) Conjugate Pairs, and/or 2.) Bi-Value Cells. Hope this helps. :-))

Normally, you would stop as soon as the Chain becomes productive, (i.e., it produces one or more Candidate eliminations). Otherwise, you can keep going, or choose to abandon it, and look for something else. These AIC's are employed in a large number of solving techniques. Just keep watching the Videos in numerical order, and you will get the hang of it.

If you watch all the Tutorials in chronological order, all your questions should eventually be answered, when the Course is complete. There are still about 12 Videos left to go. Please be patient. I am going as fast as I can.

For info on software, please write to me at sudokuswami@gmail.com Thank you.

It is usually best to wait until you have exhausted as many of the simpler techniques and patterns you can find, before trying to construct Chains. But this does not mean it is not possible to construct Chains earlier; only that it is easier to see them later on. Is there only one path? Sometimes. Can you run multiple Chains from the same starting and ending Cells? Sometimes. Try not to "guess." It is a very rare occurrence, when you cannot use logic alone, but it does happen.

Cool, thanx Swamiman.

This is discussed at length in later Videos. Please be patient, and try to go through the Tutorials in numerical order. Thank you.

Hello Samir. Your English is fine. :-)) Deciding where to begin a Chain (ANY Chain), just takes practice. Keep watching the Lessons, in numerical order, because each one leads to the next. And by the time you get to the end, you will understand everything. Good luck!

Yes. An AIC Type I begins and ends with a Strong Link, and begins and ends with the same Digit, but can have different Candidates along the way, as long as the Links alternate. If it employs all the same Digit throughout, it works the same way, but it is called an X-Chain.

Me too! Ha ha.

@@SudokuSwami If you don't like you woun't be making this super! video ;-)

Hello Brian, your question is a bit unclear. But yes, an AIC Type I or Type II will ALWAYS begin (and END) with a Strong Link. At 17:58 the first link in the Chain is between to the two Candidate 2's in Row 1. There are only TWO Candidate 2's in that Row, therefore, if one of them is False, the other MUST be True. This is the definition of a Strong Link: If A is False, then B is True. I don't know what you mean by "it is weak vertically," or that I went from "strong to strong." You judge the Link by the DIRECTION you are going, and also by where you end up. In this case, we are going from Left to Right, starting on the 2 in R1C1, going to the 2 in R1C6. This is a Strong Link. The next Link is a Weak Link going from the 2 in R1C6 to the 7 in the same Cell. Then the next Link is a Strong Link between the two Candidate 7's in Row 1. And so on, and so forth.... When making a Chain, you must be able to say, "If A is False, then B is True," and then in the next step you must be able to say, "If B is True, then C is False," etc., etc. This is the only way it will make sense.

@@SudokuSwami Thank you, and apologies for not being more clear. Hopefully I can better explain what I meant in this comment: The cell - r1c1 - showed a strong 2 - meaning that the 2 could only go horizontally in r1c2 or r1c6, but looking at the possible locations for the 2 in column 1, there were 4 other possible "vertical" locations therein. I now have a better understanding of strong numbers. Thank you for reinforcing the rule that you judge the link by the direction you are going AND that the starting link is also strong.

Yes. There are other 2's in Column 1. But they are irrelevant. The first Link in the particular Chain I am describing at 17:58 in that Video, is in Row 1; not in Column 1. And it is a Strong Link (horizontally). Starting on the 2 in R1C1, is it not possible to make a Strong Link to any other 2 in COLUMN 1, because there are FOUR Candidate 2's in that Column. I think it would be a good idea for you to go back and watch Tutorial #4 again. In any event, good luck. :-))

@@brianfielden9320 I think I detect confusion in your statements like "a strong 2", or "you linked from strong to strong", or "if a cell can be strong in one direction, but weak in another". A candidate or a cell cannot be strong (or weak); only a link can be strong (or weak). The candidate 2 in R1C1 is neither strong nor weak as this terminology does not apply to candidate numbers. But candidate 2 in R1C1 can make a strong link with candidate 2 in R1C6 (the only two candidate 2s in row 1), or weak links with any of the other candidate 2s in column 1. "Strong" and "weak" are attributes of links between two candidate numbers, not of the candidate numbers themselves, or of the cells. Makes sense?

You cannot "know." You must LOOK, and SEARCH. And it is not necessary to start with a Bi-Value Cell. It is only necessary to start with a Strong Link (i.e., a Strong Inference). There is a Strong Link between the two Candidates within any Bi-Value Cell. But there is also a Strong Link between any Conjugate Pair.

I have my own modified version of the Snyder Method that I teach in my Pencil & Paper Videos. If you want to solve the most difficult puzzles, you have to see all possible Candidates, and use the techniques from my Complete Course. The Cryptic Crackers use Snyder, because they start with no Candidates filled in, and also because most of the puzzles they solve on their Channel are baby puzzles

As far as filling in Candidates by hand......unless you have nothing better to do, why waste time doing that? Just get an app that does it automatically for you. That way if you have an hour for Sudoku, you can solve five puzzles instead of just one.

@@SudokuSwami Hi Swami, do you have your own software?

No. But send me an email, and I will give you a rundown on software. sudokuswami@gmail.com

Because of the Chain of Inferences, there is an "Effective" Strong Link between the endpoints. A Strong Link is defined as: "If A is False, then B is True." This does not preclude both endpoints from being True. The deduction is that at least ONE of the endpoints must be True, i.e., they CANNOT both be False. If the two Candidates could SEE each other, then of course, they could not both be True. But if they lie at the endpoints of an open-ended AIC, and do not see each other, then yes, they can both be True, and it does not violate the Rules. The definition for a WEAK Link is: "If A is True then B is False," which applies to two same-digit Candidates that can see each other (i.e., in the same House), or to two different-digit Candidates, within a single Cell.

@@SudokuSwami I am going through the previous videos more carefully. Each time I watch I understand more. I want to get these links down pat because they seem to be key to the entire course.

That's right. They are the key. The INFERENCE is what is important, The Links are just depictions of the Inferences. I hope you understood my reply to your earlier message..... Good luck.

​@@SudokuSwami Thank you. I have now carefully watched all the videos (main ones and adjuncts) on Strong Links and Weak Links and on AICs. I think that I now have a pretty good understanding of the concepts. However while I clearly understand that in weakly linked candidates if one is True all the others are False and that if there are more than two candidates if one is False we cannot conclude that the others are True and that even more than one candidate can be False, I still don't understand how in strong links the two endpoints can be both True. Of course I believe it because you have said so based on your thorough study of the subject matter. But, unless I missed it, nowhere in the videos is this shown or demonstrated. For instance in the case of AICs type II I can eliminate the Start Digit from the End Cell and the End Digit from the Start cell. Likewise in an AIC type II, when there are identical Bi-Value cells on both ends of the chain, I can conclude that the strongly linked candidates will be the solutions to the cells. I am comfortable with this because I have seen clear demonstrations and examples. I wish there were examples showing cases where in strong links both candidates were true. Of course this is just for my comfort and understanding and does not affect my overall understanding of a course extremely well done.

The videos in the Complete Course, are meant to be watched in chronological order. If you skip around, you will miss a lot of important concepts. I never said the two endpoints of a regular Strong Link within a House can both be True. I said the two endpoints of an AIC that do not see each other can both be True because of what I call an EFFECTIVE Strong Link. There is a big difference. From the Inferences in the AIC, (if it is properly constructed), you know that the endpoints of the Chain cannot both be False. But this does not preclude them from both being True. When you solve enough puzzles, you will see that this is a fact.

There is a Naked Pair of {7,6} in Column 3, so there cannot be a 1 in R7C3. And there is a Naked Pair of {1,3} in Row 1, which means there cannot be a 1 in R1C1.

@@SudokuSwami yes I see the naked pairs but I don't understand how they have come about. There is no 1 in row 7 and indeed 1 is shown as a possibility in columns 1, 7, 8 and 9 on that row, but it isn't shown as a possibility in row 3 and I can't fathom out why not. There are no 1s in the first three columns and 1 is shown as a possibility in row 1 and 9 of column 3, but not in row 7. I'm scratching my head as to how the naked pair was worked out. :(

I am showing isolated examples. If I showed the entire solution up to the point of each example, the Videos would be several hours long. You have to trust me, that the positions you see, have been attained by logical solving techniques. Please just try to pay attention to the point I am trying to make in each example. There is no reason to solve the entire puzzle. These are TUTORIALS.

@@SudokuSwami ok, I managed to find an AIC type II in a puzzle last night and it worked! I will keep going with the tutorials and hopefully it will all become clearer. Thank you for taking the time to respond. :)

No problem. Just remember that when a Chain calls for a Weak Link, you can use a Strong Link, but not the other way around. When you need a Strong Link, it must be a REAL Strong Link.

Find as many Strong Links as you can (i.e., Conjugate Pairs and Bi-Value Cells), and then begin to hook them up as best you can with Weak Links in between, and see what you can put together. There is no way to "know" where to start. You have to search it out. It just takes practice, and a little bit of effort on your part.

Thank you so much for replying that is above and beyond! I’m so chuffed just did my first AIC in a puzzle and got it right! Thanks you Sudoku Swami.👍