Відео

Thank you for the comment. It's very hard to get the right pace. Too slow people lose interest. Too fast and people get discouraged. My first Sudoku book taught me a lot about pace. My editor knew nothing about Sudoku. Getting the editor to say my explanation was clear took considerable effort. The chapter on the X-wing took forever!!

Thanks. I'm currently working a new video about W-Wings. I hope to publish it soon.

@@dxsudokuchannel Thanks I would like to watch it when it releases.I haven't learnt it yet so i would be excited to know about it.

@@SomeonesFriend-n1f The W-Wing video I'm working on is like the 56 types of triples video I did. For how to find W-Wings, here's my latest and best algorithm: ua-cam.com/video/iZw9gpTC9BA/v-deo.html But after you master triples, I would recommend you learn Skyscrapers and 2-String Kites next. And then X-Chains. X-Chains is very versatile and a stepping stone to the more advanced techniques.

Hodoku has a really neat way of doing difficulty rating. It assigns a weight to each puzzle solving technique. So you can customize Hodoku's rating system. Say you are really good at finding Skyscrapers and 2-String kites. You can make them have less weight. Here's the documentation on Hodoku's way of doing it: hodoku.sourceforge.net/en/docs_cre.php#rating Another popular way of rating puzzles is called SE ratings. Here's the Java program that does SE ratings: github.com/SudokuMonster/SukakuExplainer/releases/tag/v1.18.1 Just like Hodoku, to run Sukaku you have to have Java installed. The way SE ratings work is the rating number is based on the hardest technique used by the solver to solve the puzzle. This way of rating puzzles is very popular. I'm about to publish my third book. In it, I have two or three sections talking about Sudoku ratings.

This is a good question. The reason is, when givens are involved, that is, that 9 and 8 in row 9, you can't have a uniqueness situation. Uniqueness problems only occur when the four cells are values chosen by us solving the puzzle. Here's my favorite wiki page on uniqueness techniques: hodoku.sourceforge.net/en/tech_ur.php Take a closer look at this sentence: "A "Unique Rectangle" (UR) consists of four cells that occupy exactly two rows, two columns, and two boxes. All four cells have the same two candidates left..." The key thing here is "candidates" not "givens." Once givens are involved, the uniqueness problem doesn't happen. I hope this helps. Let me know and I will try to explain it further. But these are advanced Sudoku solving concepts that are tricky to explain.

Let me take a look at it and I will analyze it. Upload an image to this site: imgur.com/ Then post the link as a reply to this message and I will take a look at it. Or better yet, from Hodoku, from the "Edit" menu drop-down, select "Copy Values" command. They reply to this message and paste the 81-character string into the reply. If you are using a PC, it's Control-V to paste. With Apple, it's Command-V to paste.

@@dxsudokuchannel yeah for sure! That's it: .7..2....2.95..4...34..852..1.8..6..7.......8..2..5.1..562..73...1..68.2....8..5.

@@dxsudokuchannel i almost forgot, these are the digits .7..2....2.95..4...34..852..1.8..6..7.......8..2..5.1..562..73...1..68.2....8..5.

No problem on preferring no pencil marks. It's all good. To answer your question I've been solving Sudoku for at least 15 years now. I was coming back from Kentucky visiting relatives, my wife was driving, and I brought a Sudoku book along. I had no idea what I was doing. The first few puzzles I tried using pencil marks and paper ended badly. I was determined to figure Sudoku out. It took a while. I got pretty good with Snyder notation. Eventually, with harder puzzles, I learned you have to fill out all the pencil marks in order to solve them. One day, about 5 years ago, I found Hodoku. Unlike other software, Hodoku fills in all the pencil marks for you from the beginning to the end of solving the puzzle. At first, this seemed really strange to me. But after solving a few Puzzles Hodoku's way, I prefer how it does it. Managing the pencil marks is always the exact same thing every time. So it might as well be done by the computer software. The more interesting problem is deciding which puzzle-solving technique to use next. As I started doing more advanced puzzles, I discovered Hodoku's Learning Mode. Once I started using Hodoku's Learning mode, my Sudoku solving skills improved dramatically. That's when I started doing all the videos. After I would master a technique, I would do a video on it. I did a tutorial video on how to use Hodoku's Learning Mode: ua-cam.com/video/jPssW_W3iH8/v-deo.html Learning Mode is amazing because what it does is it gets the puzzle to the exact point where you need to find the technique you are currently learning. After searching and finding the same technique 10 or 20 times in row, you master the technique. You learn all the little wrinkles and facets to the technique. After this initial burst my skills have just been improving year to year. I became fascinated with chaining techniques. I spent several years studying this Wiki page: hodoku.sourceforge.net/en/tech_chains.php I've done a few videos on AICs and other forms of advanced chaining techniques. But last December I had an epiphany about the way to do single assumption AICs. This is my video #106 and #107. This was a real break through for me and it solved the problem of how do you find a good starting point to find an AIC in a puzzle. Btw, I'm about to publish my next book which has 60 pages on the basics of doing chaining sequences. And then in the book I solve 3 ultra extreme puzzles step-by-step. The third puzzle is the hardest possible puzzle I've ever been able to find with an SE rating of 11.9. But I actually like the way I solved the second one better which was an SE 9. I'm working on the cover art right now with a graphic artist. Very close to publishing. Anyway, thanks for the comment!!!

Thank you very much! I was looking at your Sudoku books on Amazon. Does Taming The Sudoku Dragon 2nd Edition have all the contents of the 1st Edition can I please ask? I'm looking forward to collecting and studying your books. Thanks very much for your reply! It's very helpful to me as a beginner. I do realise that beyond a certain SE grade that it's virtually impossible to solve Sudoku Puzzles without candidates. Maybe from somewhere around the SE 3.4 level or so it seems to be impractical after that to not use them.

@@MrCJHamill Yes, the 2nd Edition has everything the 1st had pretty much word for word. The 2nd edition has an extra chapter on solving puzzles without using pencil marks. And it includes a step-by-step example. I did a tutorial on solving puzzles without using pencil marks: ua-cam.com/video/-LrPxgbYKL4/v-deo.html It's titled, "Your Very First Sudoku Tutorial" because solving puzzles without using pencil marks is the way most people start out. I was reading someone's posts on Reddit a they were complaining about someone at work solving Sudoku puzzles without using pencil marks. So I became fascinated with this idea and the video referenced was the result.

You're very welcome!

Thank you for the nice comment. If you want to contribute try purchasing one of my books on Amazon. Regardless, thank you for the nice comment. My third Sudoku book is very close to being published. The book is about how the solve the hardest possible Sudoku puzzles step by step. I'll do a video review once it's out.

Sorry for the mispronunciation of the word "turbot". As I've said in the posts below where I live it's called a "fluke" or "summer flounder". Tell me which mark in the video you are referring to and I will take a look. Just so you know, a Turbot Fish pattern is an X-Chain with four nodes.

Thanks!!

I'm not sure what you mean by A not existing. An Empty Rectangle is a type of X-chain having Group Nodes. Take look at this video: ua-cam.com/video/di1aM5X0h6Y/v-deo.htmlsi=0uA1UnXq02x98rSA

Sorry I was not clear. I mean that in the exmple, two cells are marked 'A'. It does not matter if these 'A' cell contains the current number. Either way, the number can be removed from the cell that sees both 'B' cell(s) and the second cell of the 'first half of x-wing'

@@jasony001 This is the definition of a Group Node in a chaining sequence.

Take a look at video #107. It's an improved way of doing AICs

In Hodoku, under preferences, colors palette

@@dxsudokuchannel Ok thanks!!

Awesome! I'm glad the method is working. The reason why you would not search for a Hidden Triple in a house having 6 open cells is because if a Hidden Triple were present, that would mean the other 3 open cells form a Naked Triple. And since Naked Triples are easier to find, this is why I made the comment. With 8 open cells, finding Naked Quads is about equal to finding Hidden Triples. And with 9 open cells, a Naked Quintet is harder, in my opinion, than finding a Hidden Triple. Although I do find Naked Quintets occasionally. Here's another video that might help you understand subsets in general: ua-cam.com/video/24JewFezAgM/v-deo.html In the video I use the term "wrapping" but it's the same concept as "subsets".

@@dxsudokuchannel Oddly, I was reading a web page about grouping earlier today, so I'll check your vid. It was for the same reason you mentioned - easier to see the other group. I'll have to go back to the puzzle I finished and check for the naked triple (or wait for the next one) - either way, I just wanted to use the method. SO with 6 cells, look for a naked triple instead. With 9 or 8, look for the hidden triple. So.. how about 7 exactly ? PS - way too late, but I presume that was a typo "read" instead of "Red", but I like the delete method to make it even easier to see :)

The difference between Single Assumption AICs demonstrated in #107 compared to Brute Force is the following. With Brute Force, once you complete the chaining sequence, you just declare victory and solve the puzzle. With Single Assumption AICs demonstrated in #107 the logic is as follows. If the assumption candidate were "on" or set as the value of the cell, the target candidates would be killed. And if the assumption is "off" or "false", then the chaining sequence kicks in. The chaining sequence can stall. But usually what happens is before the chaining sequence solves the puzzle, you set each target candidate to "on" or "off". Once all the target candidates are set, you stop building out the chaining sequence. So the logic then becomes, if the assumption candidate is "on", the target candidates are killed. And if the chaining sequence results in a target candidate being "Off", then we must conclude it is a non-possible candidate. If this were Brute Force, we would simply be making assumptions and building out the chaining sequence until it either it stalls or solves the puzzle. In #107, we are only using the chaining sequence to eliminate target candidates. We are not using the chaining sequence to solve the puzzle. But you are correct in your suspicion because this is exactly what I do in video #111 on Brute Force. In terms of Single Assumption AICs being "the only one technique" is based on experience. The way AICs are done in #107, you can blow past almost all techniques like all the uniqueness techniques, Sue de Coq, XYZ-Wings, pretty much everything. It's only when you need things like Forcing Chains and Nets when the Single Assumption AICs stop working. Here's an example where I was forced to use something beyond Single Assumption AICs : ua-cam.com/video/ZFdL182YjXE/v-deo.html

Hi, I'm glad the video worked for you. About a year ago I had an epiphany about AICs. You need to watch this video: ua-cam.com/video/sC7WjuqGx-w/v-deo.html Compared to #96, I've expanded the kill-zone so more non-possible candidates get caught by the chaining sequence. All the videos from #107 and later are based on my new way of doing AICs. Grazie for the nice comment! Ciao

Sorry your brain hurts. Although I think Jellyfish are interesting I don't usually find too many. I find Swordfish a lot. But with harder puzzles, I generally look for AICs over Jellyfish.

@@dxsudokuchannel I'm slowly getting the hang of it, but it's going to take me a long time.

Another video you might want to look at to help is this one: ua-cam.com/video/24JewFezAgM/v-deo.html Understanding subsets is really helpful in finding Hidden Triples.

@@dxsudokuchannel Yes, that was helpful

@@dxsudokuchannel Hey, can you please look at this sudoku I'm solving? imgur 00nMfKK (can't post link cause comment gets deleted) I marked the triple candidates with your rules and ruled out the red cells (red crossed out). I'm left with the top 3 cells, where I identified a 369 pair (36, 369, 369) - if this was correct the 1258 cell would be a 1, but it isn't. Can you help me understand why that triple is wrong?

I made a sight improvement in the algorithm with this video: ua-cam.com/video/5pOJBMDxM04/v-deo.html Thanks for the nice comment!

@@dxsudokuchannel oh great, thanks for the link

Well, it's a different philosophy than the way you solved it. Maybe someday I'll tackle speed solving.

I'm not quite sure what you are asking. I can provide you an imgur link of a screenshot of it. But here's the 81-character puzzle string: ....8.....5.9.2.1...1.7.9...2.8.6.7.4.9...5.2.6.2.4.9...5.3.8.....4.7.3.....6.... Lot's of software will allow you to import this string. Let me know what you need and I will try to help you.

You're welcome 😊

Any time a house has just two cells having the same possible candidate, in the house, one of the two must be the value of its cell. When this happens, if the first cell is "off", the other cell must be "on", hence a Strong Link. And if the first cell is "on", the the other cell must be "off", hence a Weak Link. And the links are bi-directional, both Strong and Weak links exist. Remember, there's nothing special about the meaning of the word "link". All it means is there's a relationship between two pencil marks or possible candidates. Concentrate on the relationship part and the not the visualization part or pattern. The link only exists because the relationship exists first.

You make a good point. I should have thought of it. Now I'm thinking I will have to redo both beginner tutorials in the future. I'm currently working on my next book about solving ultra extreme puzzles. Once this get's done I will take a look at redoing the beginner videos. I'm really kicking myself with your comment because it's just such an obvious thing to do!!

@@dxsudokuchannel I use HoDoKu to find those obvious solutions that I kick myself for not seeing. I prefer to use Snyder notation and find the possible candidates using my own logic rather than the logic of a computer program (probably because I started out with Sudoku Guy), but I am very happy that I found your channel today, because of how thorough your explanations, how clear and easy to understand your voice and accent (or lack of), and as others have said, how totally organized and complete your content is. I can solve most of Krazy Dad's Tough puzzles and some of the Super Tough ones, but I realize that I have "miles to go before I sleep". Thank you for making all this available to us.

Wow, thanks for the great comment! I spent a long time developing the #107 AIC algorithm. When I finally got it working all of sudden I was solving Hodoku extremes I never thought I would solve!! I'm very pleased you succeeded on using this method. Sometimes it feels like there's 3 people in the world who actually get it. It's not the easiest thing to explain how to do. Thanks again for the great comment!!

Here's a nice Wiki page you might find useful: hodoku.sourceforge.net/en/tech_singles.php A "Full House/Last Digit" is pretty much the same thing as "Naked Single". I did a video where I explain how to solve a puzzle without using pencil marks. In this video, "Naked Single" is called "One Choice Remaining Type 1". I think this title is more descriptive. Type 2 in the video is a Hidden Single. Please try this video an let me know if it gave you a better explanation: ua-cam.com/video/Cj4QcqLB5iI/v-deo.html Also, here's another video I did titled "Beginner's Guide". I try to explain the Naked Single again this video: ua-cam.com/video/6WnFkrUt_10/v-deo.html Sorry video #2 did not delivery for you. Hopefully these other 2 videos will fill in any gaps.

What's missing in this explanation at this point in the video is this: After coloring a candidate in dark red, if there's only one remaining candidate, then that remaining single candidate cannot be part of a triple. This is because a triple is composed of 2 or 3 cells. So when a cell as only one candidate, it can't be part of the triple. For row 5, here's the logic of my conclusion. 8 and 9 are disqualified because there are more than 3 cells having a possible 8 or 9 candidates. But now the 7 is disqualified from being in a triple because it's the only one remaining candidate in cell R5C1. The 2 is disqualified for the same reason in cell R5C7. And the 1 is disqualified for the same reason in R5C9. Since the 7 disqualified, that means there's only one candidate remaining in cell R5C8, which disqualifies the 5. With the 5 and 7 disqualified, there's only one remaining candidate in cell R5C6 which then disqualifies the 4. I've updated this video for finding Hidden Triple algorithm in the following video: ua-cam.com/video/5pOJBMDxM04/v-deo.html UA-cam does not let you edit a video so I had to create a new video. In this updated video, I talk about disqualifying candidates when a candidate becomes the sole remaining candidate in a cell. I hope this helps.

@@dxsudokuchannel Thank you for taking the time to explain why there is no triple there. I will watch your newer video. Honestly, I still do not trust my ability to find a hidden triple in advanced puzzles. I will do my best to reason a triple in order to eliminate a candidate and if I am not sure I am correct I will check the solution to see if I was right. This of course, indicates that I'm not sure and I am guessing. I do love Suduko puzzles and want to get better. Again, thanks for your response!

@@Bergarita Sometimes it's better to understand Hidden Triples in the context of subsets. Here's a video on using Naked Triples and Naked Quads as a better way of finding Hidden Triples using a concept I call "wrapping" which is commonly known as subsets: ua-cam.com/video/24JewFezAgM/v-deo.html Keep working on it. Triples are tricky and just take some practice working on them.

With the XY-Wing, the two pincer cells create the kill zone. Since R2C8 does not share a house with R4C2, the short answer is no. The kill-zone for the XY-Wing is any cell sharing a house with both pincer cells, R1C7 and R4C2 in this case. However, the better way to convince yourself of something like this is first pretend the pivot cell R1C2=5. Then pretend the pivot cell R1C2=6. In each case, R1C2=5, and R1C2=6, what happens to each pincer cell R1C7 and R4C2 ? This idea of pretending a cell is set to a value is key to doing logic with advanced chaining sequences. The XY-Wing is in a sense a type of chaining sequence with the way the logic causes a sequence of consequence.

Great question!! By definition, a triple is composed of 3 cells where each cell has 2 or 3 of the same set of 3 candidates. I know this is a bit of a mouthful. When you have a triple, you have 3 candidates that must be chosen over the 3 cells or the house will be missing a 1-9 number. Keeping this in mind, when you have a single digit, this means the other 2 cells must be Naked or Hidden Pair because with a single digit, if it were part of triple, you would have to choose the single number or the cell would be blank. Since the other 2 digits being a pair, this would mean your single digit must be a hidden single. If it is a hidden single, you choose it as the value of the cell. If it's not a hidden single, then we must conclude it's not part of a triple. The hidden triple search algorithm just helps you see what's going in the house. You still have to be mindful of what is possible and what is not possible. I hope this explains it. I'm surprised no one has ever asked this question before. I think it comes down to when you have single digit, you must choose it as the value of the cell so it can't be part of triple. A little round about logic here. I guess the only way to see what I'm saying is by practicing finding them but also being mindful of hidden singles. I hope this helps. If it's not clear, reply where it's confusing and I will try again. Sorry if it's not clear. Tough question to explain.

I agree. Finding the X-Wing in this case, at the 12:14 mark, is way easier. I found x-cycles and Nice Loops to be a bit tricky to find. The thing about the x-cycles and the Nice Loops is the way you do the chaining sequence. In computer programming parlance the common way is a Depth First Search (DFS) like algorithm. In my later videos, especially the ones on AICs (single pattern chaining sequences are a form of AICs), I started using a Breadth First Search (BFS). The result is the same candidates get removed. But the BFS chaining sequence is really fast and easy to do. Here's a video on it: ua-cam.com/video/yq59G7rDxVo/v-deo.html And especially the following video is really fast for finding AICs: ua-cam.com/video/UDg_GjyOYaI/v-deo.html This last video is the way I solve ultra extreme puzzles on my cell phone by poking my finger around the puzzle. You have to remember the starting candidate of the chaining sequence in your head which sometimes I have forget, but even still, it works really well. Thanks for the comment!

@dxsudokuchannel thanks! I'll check them out! And thank you for your work! 🙇‍♂️

Awesome!! You and I think the same way on the same frequency. This is why I've done my videos.

Hi, I'm assuming you are talking about the 2-4 in columns 1&2 of rows 2 and 7, and at the 5:13 mark in the video. If so, here is the problem with the 2-4, the 2-4 in row 2 are givens. All the uniqueness techniques are about having more than one solution. Or a situation where you have to make a guess to solve the puzzle. Since the 2-4 in row 2 are givens, there is only one choice with the 2-4 in row 7. Since there's no guessing required to solve the puzzle, this is not an Avoidable Rectangle. I hope I got the right question.

@@dxsudokuchannel No, I was talking about the 7-1s in rows 2 and 7 but I totally missed the 2x2x2 rule so I see why it would be that now

@@headslmmer33 I once had a huge argument with someone about the 2-2-2 rule. I was trying to convince them if it were not 2-2-2 it could not be ambiguous. I could see it intuitive but I don't think I was able to convince them with a proof or with language. At some point I may spend more time on this idea. At some point you need to take a look at AICs. AICs are somewhat like a universal puzzle-solving technique and they get past the UR type techniques. I still do UR Type 1s and 2s because they are so easy to find.

Dude! It's a work of art!! That's amazing puzzle. Really nice constellation of givens. It's definitely on my queue to solve. In the 3 video of series, I talk about creating puzzles using masking. I'm in the process of developing some Python programs for creating puzzles. I would love to hear your approach so lets setup a zoom session. It can't be this month, I'm crazy busy. July is going to ease up for me. So I will contact you. Just so you know, you can send me messages on Reddit using the handle dxSudoku. Again, the puzzle you made is really great!! Keep going!!

At which mark in the video are you seeing the UR Type 1. There's no right or wrong way to solve a puzzle. If you see a UR Type 1, then use it to solve the puzzle and don't be confused. The UR Type 1 logic is easy to understand because it creates a set of 4 Naked Pairs if you do not choose wisely. The result of the Naked Pairs is there's no way to solve the puzzle without guessing, or in other words, the puzzle has more than one solution because you have two sets of choices on how to solve the puzzle. I did a video just on the logic of the UR Type 1 show the 4 sets of Naked Pairs if you are interested: ua-cam.com/video/RQmgJryCa-c/v-deo.html With Bug+1, the logic is very similar except if you do not choose the one candidate in the cell having 3 pencil marks, what happens is you have N number of bivalue cells. With all the N cells having bivalue pencil marks, again, you have to guess how to solve the puzzle. And with N bivalue cells there are multiple guesses beyond just two like with UR Type1. So the logic behind all the UR techniques is we assume our puzzle has only one solution, and therefore, we can remove pencil marks based on this assumption. However, I have to honest with you. There are two opposing opinions on whether or not a puzzle having more than one solution is invalid. I am on the side that claims a puzzle having more than one solution is okay, valid, and is not a problem. To solve it, you just show a solution, it doesn't matter which one. As long as you have a solution grid that abides by the one of each number in each house rule your have solved the puzzle. I have solved many puzzles having multiple solutions. They can be quite challenging!

The beginning of the video 0:14 the first example. We have cells with 5 and 3 They're in 2 rows and 2 columns and one of them has a 9. With that logic the top right of the rectangle (row 4 column 5) should be a 9

Let's run the algorithm. Start with column 1, it adds rows 2 and 9. Next, add column 3. It adds rows 2, 5, and 8. So far we have 2 columns and 3 rows. Then add column 6 which adds rows 2 and 5. So we still have rows 2, 5, and 8. And now we have three columns 1, 3, and 6. We add the final column 7 which adds rows 5, 8, and 9. So we have four columns which is okay: 1, 3, 6, and 7. And we have four rows: 2, 5, 8, and 9 which is also okay. Nice catch! It looks like this would eliminate many of the same target candidates in the example.

@@dxsudokuchannel ❤️

What digit?

​@@dxsudokuchannel1

Yes, you found one with those columns and rows.

Thanks!!

Here's a really good wiki page on the most common puzzle-solving techniques if you are interested: hodoku.sourceforge.net/en/tech_intro.php All the fish are X-Chain variants. Just look for X-Chains with Group Nodes and call it the day. Or even better yet, just use AICs and solve everything.

Merci pour le beau commentaire. Cette façon de trouver les triples cachés est en fait très utile. Bien que je recherche habituellement des triples nus, des quads et même des quintettes. Je les vois juste plus rapidement que de faire des éliminations de candidats.

At what mark in the video? I will check.

@@dxsudokuchannel 5:01

The 69-R1C3-Pivot with 29-R6C3-Wing1 and 26-R1C8-Wing2 do form an XY-Wing. The kill zone would be the intersection point of the two wing cells which has the number 3 as a given. But the three cells do form an XY-Wing. When I created these practice exercises there could be more than one solution. If you are interested in creating your own practice exercises check out this video: ua-cam.com/video/jPssW_W3iH8/v-deo.html

If the SE 11.9 puzzle there were lots of uniqueness techniques (type 1s and type 2s). However, theoretically, although I never needed to do it, you know how I have my cell-phone way of doing the AICs with extensions, you could use this style of doing of chaining do a next level up chaining sequence to prove the current Forcing Chain's verity or contradiction. But so far I've never seen anything so complicated that the first level Forcing Net required using AICs with extensions to prove out the Forcing Net. At most, when stuck, I've used X-Chains a lot. I think in this video there's a Skyscraper which is an X-Chain variant. The other question I've been pondering is the idea of branch points within the build-out of the chaining sequence, that is, the nature of ambiguity within the constellation of givens. And the last thing still hanging on thinking about, is doing Forcing Chains and Nets this way still a form of guessing. There are brief moments where I think it may be and then I argue myself back from the ledge with the realization the constellation of givens are dictating the sequence of the chaining sequence so it's logic. These three questions may be around for a while! Thanks for you comments!! I do think Forcing Chains and Nets are a sort of "end-of-the-road" when it comes to puzzle-solving techniques. I've been working on a new series of videos for doing Python programming with Sudoku. In this new series, I'm going to create a bunch of programs for creating new puzzles and providing more advanced analysis of Sudoku puzzles at a certain point in a solution. I'm also interested in an idea I've been kicking around with regards to classifying puzzles according to different sets of solution paths.

My thoughts exactly!! I was literally stunned when I saw this result. I've been working on this puzzle forever! So the idea that this is even possible is very interesting to me. There's a certain about of complexity and ambiguity that can occur within the constellation of givens. So I've currently thinking on ways this could be leverage as a way of figuring the least amount of steps, or in this case, assumptions ever needed when solving a puzzle with a Forcing Chain and Nets. I also fascinated by the way this puzzle required 38 assumptions just to get 1 value set. So here is my challenge to anyone who tries to solve this puzzle. What is the best possible way with the least amount of work just to get ONE cell set to its proper value in the solution of this puzzle?

Yes, there may be more than 1. But in the exercise I only did one. If you are interested in generating your own exercises, I did a video on how to do it: ua-cam.com/video/jPssW_W3iH8/v-deo.html You also might find this video interesting: ua-cam.com/video/di1aM5X0h6Y/v-deo.html And this one will take you skills to another level: ua-cam.com/video/QvqGjXyPrIU/v-deo.html Make sure when you search for X-Chains you also include Group Nodes in the chaining sequence. It opens up all kinds of new candidate eliminations.

You are correct. This is the definition of a Hidden Triple. The method in the video is just an aid in helping people see which cells contain a Hidden Triple. Here's another version of the same technique but for cell-phone apps: ua-cam.com/video/UDg_GjyOYaI/v-deo.html You have good Sudoku eyes. If you haven't done already, you need to start looking at AICs. AICs are pretty much a universal puzzle-solving technique. So I end up doing AICs most of time rather than looking for stuff like XY-Chains, Uniqueness Techniques, Remote Pairs, and even X-Chains.

Yes, but the Quintet has 5 cells instead of four. But it's probably easier to look for a Hidden Triple than Quintet because a 2-2-2-2-2 Quintet would be very hard to see. Here's my new video on how to find Hidden Triples: ua-cam.com/video/33LnPOUH6Xo/v-deo.html

Which square cannot contain 3 or 7? At this mark in the video, I was showing either all the 37-greens are on, or all the 37-purples on on. It's one or the other. Also, take a look at this video. It's the same thing but searching for a good Remote Pair result like finding an X-Chain: ua-cam.com/video/d9IJdbFJ38w/v-deo.html