This video was outstanding. I searched for Sashimi x-wings because I was unfamiliar with this technique and your explanation was complete, loaded with examples and gave me Insite I did not have. Thank you this gift.
It took a while but I finally got to a point in your course where I learned something brand new to me! I’m so excited. Grinning ear to ear. Can’t wait to find a puzzle to use these new skills on. Thanks SS!
Thank you Sudoku Swami for these great videos. They are the most thorough out there. Other tutorials leave me with more questions than answers since they don't show the whole picture, but your vids are very helpful. The X wing and finned X wing tricks help the most... Thank you.
Your explanations are a lot better than other videos tutorials I have seen. Thanks. Best wishes from an island in the Mediterranean Sea, full of FISHES.
Swami, I occasionally run into a puzzle that seems impossible. I rewatched your video on finned X wings. Tonight I'm on a puzzle that seemed impossible. As a last resort I actually looked for a finned X wing. I found one that gave me one elimination, it happened to be a bi value cell and the puzzle was solved. I will never pass over any of your videos again!!! Thanks, Richard
For Beautiful Custom T-Shirts & Coffee Mugs featuring the Swami Logo, and also for Selected Classical Piano Pieces played by me, now available via Digital Download, please visit the Sudoku Swami Gift Shop! sudoku-swami.shopify.com
I finally get it. While other videos I have observed on this topic made the techniques more complicated than they need to be, the Swami's explanation is spot on and easy to follow. Thanks Senior Swami!!
omg, thank you so much. FINALLY I can understand this. you’re absolutely right, there’s no youtube tutorial where they explain about other fins in the same blocks. that’s why I kept messing up, it was so frustrating. THANK YOU!!!!!
Thanks so much for the detailed explanations of Finned and Sashimi X-Wings. I find videos such as this the best way to learn concepts (Sudoku or otherwise). I can read material till the cows come home but often never grasp a concept. Thanks so much!
Excellent tutorial, thank you, in my eagerness to learn, I moved on from this some time ago and I am now able to do more advanced puzzles. But have now revised it for the second time, and the mist begins to clear! Well done Sudoku Swami!
i guess Im asking randomly but does any of you know of a method to log back into an Instagram account..? I stupidly forgot the login password. I would appreciate any tricks you can give me!
@Brantley Alan i really appreciate your reply. I got to the site on google and im in the hacking process atm. Takes quite some time so I will get back to you later when my account password hopefully is recovered.
Swami, I give you a lot of credit for the success and the enjoyment i have playing sudoku. I just had a first. A finned X wing with two eliminations. I've had lots of singles but this is the first double. It solved the puzzle. With sudoku it's always something different, you never quit learning!! Richard Vanderpool
I am going through your videos. They are outstanding. They are clear. They are concise. You make difficult concepts understandable. Had you been my professor in college physics, I would have understood quantum physics, and had you been a professor in law school, I would have actually understood the Rule Against Perpetuities. (Challenge: Do a video explaining that one!)
I have been stuck on one level for weeks. I wouldn't move up because I correctly resolved only some of the finned fish. I was looking for a different explanation and clearly found it on your video. Your video is a BETTER explanation. Now I KNOW it when I see it, and can prove it! I implore anyone who wants to learn this to check out this video. I am going to check out your others. Thanks again.
Great. Thanks. Just remember, that if you see a Sashimi X-Wing with only ONE Fin, it is better to treat it as a Skyscraper. If the Sashimi X-Wing has TWO Fins, then you are stuck with only the possible eliminations within the same Block as the Fins. Good luck.
Glad to hear it. Thank you for your Subscription. To get the most out of my Course, it is best to watch all the Tutorials in chronological order. Good luck!
Hello Sudoku Swami, Thank you for your tutorial series, even though I’m fairly advanced in my understanding, I’m learning a lot from you. Can I ask what app you are using, as I cannot find an app that allows me to mark the sudoku grid like you do, which makes looking for various things like AICs, loops, empty rectangles, x wings, etc, etc very difficult.
A big thank you for a well presented materpiece on incomplete X-wings. I've looked at many other youtube channels and ended up confused and frustrated. Now time to try and find those hidded incomplete X-Wings. P.S. What software do you use - it is real handy being able to highlight / filter by number
Great stuff. W/the fin, why does the fin affect the other row or column? like 4:50 I get why you can't eliminate the 5's in column 3, row 2, 8 &9. I don't get why you can't eliminate the 5's in column 5, row 3, 6 & 8. Can show me an example where, in the end, there won't be a 5 in either Column 5 row 1 or Column 5 row 4. (FTR I've looked this up at other sudoku sites and they all have it like you. So I'm 99% I'm wrong, I just can't see it.)
What you are failng to recognize, is that because of the presence of the Fin (the 5 in R4C2) this is NOT a "standard" X-Wing. Therefore there is no logical reason you could eliminate the 5's in ANY of the Cells you listed in your question. However, because of the Fin, you CAN make eliminations in the Block that contains the Fin, but ONLY that Block. The reason for this, is that you can only make logical conclusions about this configuration within that Block. The 5's in R5C3 and R6C3 are False whether the Fin is there (and True) or not there. If the Fin is not there (i.e., False), then it is an X-Wing, and the 5's in the red-colored Cells would be False. And if the Fin is True, those same two Candidates would also be False. So they are False either way, and can safely be eliminated. But you cannot draw any conclusions about any of the other 5's in Columns 3 & 5.
5:41 you say "fin has absolutely no effect on other 3 corners of X wing"....but, if fin was true, the bottom right 5 of the x wing(which is one of the other 3 corners of the x wing you mentioned) will be false.....sorry i dont get that part?
The example at 5:41 is a hand-drawn diagram. It is not a real puzzle. The point is, that Candidate eliminations resulting from a Finned or Sashimi X-Wing can only be made in the same Block that contains the Fin(s).
I have had to watch this so many times as I keep making mistakes on spotting sashimi X wings I’ve finally realised the trick to spotting the sashimi or finned X wing is that the two conjugate pairs (in parallel rows or columns) are only messed up by extra candidates in ONE block. I know you said it in the previous tutorial but I didn’t get that until now! Is this the right way to look for these patterns?
Fins can only occur in ONE Block. Eliminations can only be made in THAT same Block. For the Sashimi Version: If there are TWO Fins, treat it as an X-Wing. If there is only ONE Fin, treat it as a Skyscraper.
HI Ellis and Brantley, Sorry I don't know anything about Instagram, though I'm intrigued to know why you ask me? and why on this site!?! I do know a bit about Sudoku though mainly thanks to Sudoku Swami!
Why are sashimi x-wings called sashimi? My theory is that in real sashimi, the fin is removed from the body of the fish. In sashimi x wings, it's the same thing. The corner of the x wing is cut off, and the fin is separated from the x wing "fish"! 🐟🐠🐡🦈
The examples in my Complete Course Videos, are chosen at random, and are not meant to be an exhaustive study of each position. I am not trying to "solve" the entire puzzle. I am only demonstrating the particular technique, one example at a time. The Base Sets I point out are only relevant to the particular X-Wing I have chosen as my example.
Sir, AT 21:26(see time) CLip above For candidate 1 , You have seleected R1 you selected C1 & C6 ...so if we select R4 C1 & C6 as our set & R4 C4 can be a fin?
No. The Candidate 1 in R4C7 is not in the same Column as the Candidate 1 in R1C6. The Cover Sets are Columns 1 & 6. You cannot have any Candidates in Column 7. All Base Candidates must lie in the Cover Sets. If the 1 in R4C7, was NOT there, then your assumption would be correct.
Great thanks for all the hard work. I have gone through all your previous tutorials. You are thorough and structured to clearly explain all the techniques. Sashimi refers to fish (or raw meat) being cut into thin pieces. Could this be the reason to call this pattern the Sashimi X-Wing as it is a fish with one corner cut off with the candidate digit?
Some people equate the term Sashimi with being a "degenerate" fish. They argue that it is not really a Fish Pattern at all, because it is incomplete. But in my opinion, if the eliminations are valid, it doesn't really matter what you call it. I still like your analysis the best.
Swami my question pertains to selection of Sashimi fins as it seems other possibilities exist. On video example at 21:48, you address candidate 8 as you do . Is the 9 on R2C6 not possible for sashimi, thus making the 8 fin at R2C5? If so, that would eliminate the 8 of the BV 4,8 at R3C6. Same goes for Sashimi 3 at R1C6 with fins at R1C3/4? If one can eliminate a candidate of a bivalue cell, that would be more fruitful. Please and thank you!
Hello I am in the process of moving from one country to another. I do not have time to examine your question right now. Please give me a couple of weeks, and I will give you a full explanation and reply, as soon as I am able. Thank you.
Yes they see the fins. But eliminations in ANY X-Wing can only occur in the Cover Sets, which in this case are Rows 1 and 6. And the only 7 that is in either Row 1 or Row 6, AND can see the fins, is the 7 in R1C9.
So. Should the X-wing exist within two blocks instead of four, it seems to me that it would allow for fins in BOTH base sets, as long as they are in the same block, and the result would be the same: either the wing is true or one of the fins is true. Right?
Fins Can ONLY be in ONE of the Blocks. Let's say your X-Wing lies in Blocks 1 & 3. If the Base Sets are in the Columns, there would only be room for ONE Fin, which would allow for 4 possible eliminations in that same Block. If the Base Sets are in the ROWS, then there would be room for 4 Fins, but only ONE possible elimination. REMEMBER: All eliminated Candidates MUST SEE ALL THE FINS.
@@SudokuSwami Yep, so the possible one elimination then would take place in the cell in-between or beside the x-wing cells in that block. Thank you again, I feel I am getting wiser every day 🙂!
Hmmm hold it. Let us say I have my X-wing in Blocks 1 and 3, and base sets in the Rows. The Block 3 X-wing cells are, say, in R1C7 and R3C7, and Fins in say R1C8 and R3C8. Now, they are all in the same Block, no? Only one of them is true, but any other candidate in that Block would see them all, both the X-wing cells and the Fins.. it seems to me this would allow for max 3 eliminations (R2C7,C8,R9). Regardless of whether there are extra Fins in R1C9 or R3 C9 or not. Because everything happens in one block, the cover set plays no role. Am I missing something here?
What you are forgetting, is that a Candidate can only be eliminated, if it would be eliminated by the X-Wing, if the Fins were NOT there. In your case that could only be in Cell R2C7. A Candidate in any other Cell in that Block would NOT be eliminated by the X-Wing alone. The eliminated Candidate(s) must be False EITHER WAY. That is the reason the technique works.
Fins can only occur in ONE Block. If there are Fins in more than one of the Blocks, the technique will not work. Eliminations can only be made in the Block containing the Fins. This is explained multiple times in the Video.
I know now how sashimi works, but I’m not sure if I understand the logic. So If one of the intersections of the incomplete X-wing is allready filled in with another digit, than I can conclude that in the row or collum where the other digit is standing, that in that row or collum should have been a conjugate pair, and that the conjugate pair of that collum or row can be solved? That’s the logic? Is it that simple? And if there is an incomplete X-wing with one of the intersections missing I can’t conclude anything unless there is a fin in the block where the missing digit is situated. Than it works the same as a finned X-wing. Correct?
I should have said: “if the canditate of the “X-wing” is missing in one of the intersections of the incomplete X-wing” and not “with one of the intersections missing” Can you still follow me? 😅
Hello Remy. All your questions are answered in the Video. Please watch it again, and listen carefully to what I am saying, always read the text that I write on each side of the puzzle, watch my demonstrations, and study the Examples. There are 6 Examples of each Type: Finned and Sashimi. Video #11-A has even MORE Examples. Also, if you have a Candidate missing in one of the Base Sets of an X-Wing, and there is no Fin, then you will end up with TWO Naked Singles. Good luck.
Dear friend, As always, thanks for your quick responce! You are the the nicest person of all! You have invested a lot of work in this. The only reason you are doing this, is to help others unconditionally. And I can tell you that you are doing a great job!! You said in your introduction video that solving sudo puzzles reduces the chanches for demention and Alzeimer. Well, I can tell you that is helps for more conditions. I am suffering from an Anxiety Disorder, and I found out that solving sudoku puzzles helps me to consentrate and focus. It helps me to cope with my problem. But to a certain point I was suffering with the advanced techniques. it's amazing what you do by making me feel better. I couldn’t find any logic explontions on the internet untill I found your channel. The way you explain all the techniques is crystal clear! I am eternally grateful for your efforts! I posted my question before I sow your examples in the video and before I checked your video #11-A. Next time I will post questions AFTER I have watched all examples and alfter I have seen the additional explained videos. As always, I have made notes of your lesson. Below, you will find a copy of my notes. Those are without the screenshots I made. *** Finned and sashimi X wings A) FINNED X-WINGS Take notice that eliminations can only be made in the block where the fin is situated! The fin is always situated in the collums or rows of the BASE SETS The BLEU cell is the FIN 1. If the fin is FALSE, then you have a X-wing and the RED CELLS can be eliminated. 2. If the fin is TRUE, then all other candidates in the block can be eliminated, including the RED CELLS. VERRY IMPORTAND NOTICE!!: This technique works ONLY if there are 1 or 2 fins in ONE BLOCK on the X-wing! Now when we look for a verity for the fins , there are TWO posibilities for them to occur: 1. ONE of them is thrue 2. BOTH of them are false There is no third posibility, becouse they can’t both be true. 1. So when both of them are false, then you have a X-wing and the red cells can be eliminated 2. When one of them is thrue, all other candidates in that block can be eliminated, including the red cells. B) SASHIMI X WINGS (or finned shamimi) A SASHIMI is an X-wing with one of the candidates missing in one of the intersections or if one of the intersections is taken by another digit and if there is a fin in the block where the missing or taken cell is situated. TAKE NOTICE that if one of the cells is taken by another digit, and there is no fin, than you simply have a naked single!
At Time Stamp 8:11, you have just talked about the fin in Blue having two candidates c1r4,c2r4 in block 4. Looks to me as if the Red Candidates in C3r5,c4r6 now could be the fin and the blue cells could be eliminated. That is what is keeping me from seeing the Fin Fish. Can you explane why my logic is wrong . Nobody ever talks about how to validate the correct fin if it's depicted as in Time Stamp 8:11. Or, I've missed something. So in block four, why couldn't the rolls be reversed Blue becomes Red and Red becomes blue. Thanks
Any and all Fins must lie in the Base Sets. The Candidate 5's in the Red Cells DO NOT lie in the Base Sets. The two Base Sets in this diagram at 8:11 are Row 1 & Row 4.
@@SudokuSwami I agree! Now that I did what you said and took all the lessons starting at lession 1, my next lession is 12 Swordfish. I posted when I was without knowledge, sorry. Your lessons are awesome!!!
@@SudokuSwami greetings sir! This is the particular point that I believe you do not explicitly and specifically hammer that point home. If one doesn't know how to identify the base set, then the subsequent identification of the fin is very difficult. And then perhaps showing an example as to why a certain candidate might look like a fin but it is not would truly results in understanding and excellent grasp of the topic. Thank you!
On the final example what about the x-wing you'd have if the bottom candidates were blocks 5 and 7 of row 8 with a fin twixt the two? Why pick the Sashimi x-wing over the Finned x-wing? You can't have an x-wing using rows 5 and seven cause you can only have one f'd candidate block, right? Does the Sashimi fin take on the value of the missing candidate and its opposite corner? This is like a naked pair without matching numbers. A naked uneven pair. A Sashimi pair. Just pick a number from the block next to it. A triple is a finned pair... How do you play checkers? I think it's past Stephens' bedtime. iosleepy says my iPhone...
Stephen, your question is so convoluted, vague and unclear, that it is very difficult for me to give you an answer. You need to be a little more precise in your description. But if you are asking about using Row 8 as a Base Set, with Row 2 as the other Base Set, yes, this forms a standard Finned X-Wing. However, it would be pointless, as there are no other Candidate 9's in R7C5 or R9C5 to eliminate. The only productive result, is what is shown in the example; A Sashimi X-Wing with Fins in R5C4 & R5C6, and eliminations in R4C5 & R6C5. :-))
Convoluted, vague and unclear. Love it. I WAS pretty tired. So. Are multiple x-wings something that ever happens or can you stop looking when you find one?
Yes, multiple X-Wings are possible. But let's define "multiple." Of course you could have several X-Wings in a puzzle, each using a different "Fish-Digit." And you could have multiple X-Wings (including Regular, Finned, and Sashimi) on the SAME Fish-Digit Candidate. BUT......and this is a BIG BUT....once you use 4 instances of that Candidate (or 3 with a Sashimi), to form an X-Wing, you will not find another X-Wing that contains those same 4 (or 3) instances of that Candidate. There can be other X-Wings using that Same-Digit Candidate, but they must be completely separate. If you think about it hard enough, you will realize that it would be impossible to use the same Candidate (or Candidates) for more than one X-Wing.
With Sudoku I've learned that if it Can happen it Will happen. 5 blocks each with the same 5 numbers in them, etc. Are you a teacher in real life too Swamiman? OK. Back to lesson 12.
Hi Swami, I have a question about fins. They only work in the blocks they are located in. Now if one of the fins in the base cell is true then the candidates in the cover cells in the block can be eliminated, I totally agree with that. But if the fins are false then the eliminations are carried out in the block concerned by virtue of the X Wing. So my question is: why (if the X Wing is intact) the eliminations are only made in the cover cells within the block and not the other cover cells? I am sure it is true, but I seem to have missed the demonstration. Thanks!
It is because YOU DON'T KNOW yet, whether the Fins are True or False. So you can ONLY make eliminations that would be valid EITHER WAY. Therefore, you can only eliminate candidates that can SEE ALL THE FINS. You cannot make any deductions about any of the other candidates in the Cover Sets. You can only eliminate Candidates that lie in the same Block as the Fins.
That's the reason! Now that you've explained it seems obvious and one of the foundations of the whole course. Great! Thanks! I am going through the videos again to reinforce and maintain what I have learned! Outstanding course!
If the Fin in R4C2 was definitely TRUE, THEN you could eliminate that 5 in R6C1. But if the Fin is FALSE, it does NOT tell you anything about the 5 in R6C1. You can only eliminate Candidates that would be False EITHER WAY. This applies ONLY to the two 5's in the Red-Colored Cells, R5C3 & R6C3, in this particular diagram.
Only same-digit Candidates that lie in the Cover Sets can be eliminated, because they would be False either way. You cannot make any deductions about OTHER same-digit Candidates that DO NOT lie in the Cover Sets, even though they may lie in the same Block (box) as the Fin or Fins.
The key word is "OR." Either the Fin is True or it is a valid X-Wing. It is one case, or the other. Not both. So you can only eliminate Candidates that would be False either way, as explained in my first response.
One thing you are apparently forgetting, is that if the Fin is False, resulting in a valid X-Wing, only TWO of the four X-Wing Candidates will be True. One diagonal pair will be True, and the other diagonal pair will be False. This is why you cannot make any other eliminations in the Block with the Fin(s), except for those that lie in one of the Cover Sets.
That's bad grammar, my friend. It should be: "The language and tone in this video ARE horrible." Nevertheless, it's so nice of you to post such a friendly, thoughtful, and helpful comment. Thank you.
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!
This video was outstanding. I searched for Sashimi x-wings because I was unfamiliar with this technique and your explanation was complete, loaded with examples and gave me Insite I did not have. Thank you this gift.
It took a while but I finally got to a point in your course where I learned something brand new to me! I’m so excited. Grinning ear to ear. Can’t wait to find a puzzle to use these new skills on. Thanks SS!
Thumbs up for the best X-wing tutorial on RUclips. Thank you for your effort that you put into the making of this videos.
Thank you Sudoku Swami for these great videos. They are the most thorough out there. Other tutorials leave me with more questions than answers since they don't show the whole picture, but your vids are very helpful. The X wing and finned X wing tricks help the most... Thank you.
Thanks for your very kind comment. Welcome aboard! Good luck. :-))
I just watched a couple of your Videos..... Nicely done! I am a big fan of Amsterdam. I love the Van Gogh Museum there...
@@SudokuSwami Thank you... It's been home now for many years... still love it...
Your explanations are a lot better than other videos tutorials I have seen. Thanks. Best wishes from an island in the Mediterranean Sea, full of FISHES.
First finned fish tutorial I've seen explaining how to identify find. Most just seem to assume the viewer knows where the fin is. Thank you.
Saying again what has already been said here many times:
BRAVO for clarity!!! THANK YOU.👍👍
Swami, I occasionally run into a puzzle that seems impossible. I rewatched your video on finned X wings. Tonight I'm on a puzzle that seemed impossible. As a last resort I actually looked for a finned X wing. I found one that gave me one elimination, it happened to be a bi value cell and the puzzle was solved. I will never pass over any of your videos again!!!
Thanks, Richard
There ya go... Fantastic!
This is the BEST explanation of finned x wing i have seen. thank you very much sir for this video.
For Beautiful Custom T-Shirts & Coffee Mugs featuring the Swami Logo, and also for Selected Classical Piano Pieces played by me, now available via Digital Download, please visit the Sudoku Swami Gift Shop! sudoku-swami.shopify.com
most useful tutorial for advanced puzzles. explained beautifully with lot of examples. neat explanation to the point.
Thanks very much for your comment. Greatly appreciated.
I finally get it. While other videos I have observed on this topic made the techniques more complicated than they need to be, the Swami's explanation is spot on and easy to follow. Thanks Senior Swami!!
omg, thank you so much. FINALLY I can understand this. you’re absolutely right, there’s no youtube tutorial where they explain about other fins in the same blocks. that’s why I kept messing up, it was so frustrating. THANK YOU!!!!!
Thanks so much for the detailed explanations of Finned and Sashimi X-Wings. I find videos such as this the best way to learn concepts (Sudoku or otherwise). I can read material till the cows come home but often never grasp a concept. Thanks so much!
Hello Brian, thanks for your interest in my Tutorials. Good luck! :-))
Excellent tutorial, thank you, in my eagerness to learn, I moved on from this some time ago and I am now able to do more advanced puzzles. But have now revised it for the second time, and the mist begins to clear! Well done Sudoku Swami!
i guess Im asking randomly but does any of you know of a method to log back into an Instagram account..?
I stupidly forgot the login password. I would appreciate any tricks you can give me!
@Ellis Clyde instablaster :)
@Brantley Alan i really appreciate your reply. I got to the site on google and im in the hacking process atm.
Takes quite some time so I will get back to you later when my account password hopefully is recovered.
@Brantley Alan it worked and I finally got access to my account again. I'm so happy:D
Thank you so much you saved my account !
@Ellis Clyde glad I could help xD
Swami, I give you a lot of credit for the success and the enjoyment i have playing sudoku. I just had a first. A finned X wing with two eliminations. I've had lots of singles but this is the first double. It solved the puzzle. With sudoku it's always something different, you never quit learning!!
Richard Vanderpool
I am going through your videos. They are outstanding. They are clear. They are concise. You make difficult concepts understandable. Had you been my professor in college physics, I would have understood quantum physics, and had you been a professor in law school, I would have actually understood the Rule Against Perpetuities. (Challenge: Do a video explaining that one!)
Thanks very much. I really appreciate your comment. And as for Perpetuities, I think I'll stick with Sashimi X-Wings.
Your video presentation was a really clear explanation - I'm now solving these. Thank you so much. Cheers
Glad to hear it. Good luck, and stay safe!
Was able to solve a puzzle where I found a Sashimi X Wing after learning your lesson 11. Thanks for your great teaching.
Congratulations! Glad to hear it....
awesome video the best i've seen on finned x wing , chapeau
Absolutely outstanding! Thank you so much!!
This was the clearest explanation of these tricks that I've seen on the Web. Thank you!
Thank you so much for your explanation, I finally get it!💗
This is a good one for me. I was not aware of the Shasimi X-Wing technique.
Best explanations ever of these concepts. Thanks!!
Glad to hear it, DeWayne. Thanks for your interest and support.
I have been stuck on one level for weeks. I wouldn't move up because I correctly resolved only some of the finned fish. I was looking for a different explanation and clearly found it on your video. Your video is a BETTER explanation. Now I KNOW it when I see it, and can prove it! I implore anyone who wants to learn this to check out this video. I am going to check out your others. Thanks again.
Great. Thanks. Just remember, that if you see a Sashimi X-Wing with only ONE Fin, it is better to treat it as a Skyscraper. If the Sashimi X-Wing has TWO Fins, then you are stuck with only the possible eliminations within the same Block as the Fins. Good luck.
How can I get the Sudoku apps iPad that you are using
Thanks so much. I just use this technique to solve my 6-hours-sodoku.
Great video!
Glad to hear it. Thank you for your Subscription. To get the most out of my Course, it is best to watch all the Tutorials in chronological order. Good luck!
WOW! I feel like I'm starting to understand this. Thanx.
This is amazing.
Hello Sudoku Swami,
Thank you for your tutorial series, even though I’m fairly advanced in my understanding, I’m learning a lot from you.
Can I ask what app you are using, as I cannot find an app that allows me to mark the sudoku grid like you do, which makes looking for various things like AICs, loops, empty rectangles, x wings, etc, etc very difficult.
Glad to hear it. Good luck!
amazing tip. Thank you
Yep I’m starting to get it!
Hi, Loving the videos, very helpful. Do you have a link to the grid you use, I work with pencil and paper but very messy and gets confusing. Thanks
A big thank you for a well presented materpiece on incomplete X-wings. I've looked at many other youtube channels and ended up confused and frustrated. Now time to try and find those hidded incomplete X-Wings.
P.S. What software do you use - it is real handy being able to highlight / filter by number
very cool
Great stuff.
W/the fin, why does the fin affect the other row or column? like 4:50 I get why you can't eliminate the 5's in column 3, row 2, 8 &9.
I don't get why you can't eliminate the 5's in column 5, row 3, 6 & 8.
Can show me an example where, in the end, there won't be a 5 in either Column 5 row 1 or Column 5 row 4.
(FTR I've looked this up at other sudoku sites and they all have it like you. So I'm 99% I'm wrong, I just can't see it.)
What you are failng to recognize, is that because of the presence of the Fin (the 5 in R4C2) this is NOT a "standard" X-Wing. Therefore there is no logical reason you could eliminate the 5's in ANY of the Cells you listed in your question. However, because of the Fin, you CAN make eliminations in the Block that contains the Fin, but ONLY that Block. The reason for this, is that you can only make logical conclusions about this configuration within that Block. The 5's in R5C3 and R6C3 are False whether the Fin is there (and True) or not there. If the Fin is not there (i.e., False), then it is an X-Wing, and the 5's in the red-colored Cells would be False. And if the Fin is True, those same two Candidates would also be False. So they are False either way, and can safely be eliminated. But you cannot draw any conclusions about any of the other 5's in Columns 3 & 5.
Nice.
5:41 you say "fin has absolutely no effect on other 3 corners of X wing"....but, if fin was true, the bottom right 5 of the x wing(which is one of the other 3 corners of the x wing you mentioned) will be false.....sorry i dont get that part?
The example at 5:41 is a hand-drawn diagram. It is not a real puzzle. The point is, that Candidate eliminations resulting from a Finned or Sashimi X-Wing can only be made in the same Block that contains the Fin(s).
I have had to watch this so many times as I keep making mistakes on spotting sashimi X wings I’ve finally realised the trick to spotting the sashimi or finned X wing is that the two conjugate pairs (in parallel rows or columns) are only messed up by extra candidates in ONE block. I know you said it in the previous tutorial but I didn’t get that until now! Is this the right way to look for these patterns?
Fins can only occur in ONE Block. Eliminations can only be made in THAT same Block. For the Sashimi Version: If there are TWO Fins, treat it as an X-Wing. If there is only ONE Fin, treat it as a Skyscraper.
HI Ellis and Brantley, Sorry I don't know anything about Instagram, though I'm intrigued to know why you ask me? and why on this site!?!
I do know a bit about Sudoku though mainly thanks to Sudoku Swami!
Why are sashimi x-wings called sashimi? My theory is that in real sashimi, the fin is removed from the body of the fish. In sashimi x wings, it's the same thing. The corner of the x wing is cut off, and the fin is separated from the x wing "fish"! 🐟🐠🐡🦈
at 11:11 i see so many X wings of 8...why did u only choose one X wing to look at, and called them the 'base' sets??
The examples in my Complete Course Videos, are chosen at random, and are not meant to be an exhaustive study of each position. I am not trying to "solve" the entire puzzle. I am only demonstrating the particular technique, one example at a time. The Base Sets I point out are only relevant to the particular X-Wing I have chosen as my example.
Sir, AT 21:26(see time) CLip above For candidate 1 , You have seleected R1 you selected C1 & C6 ...so if we select R4 C1 & C6 as our set & R4 C4 can be a fin?
No. The Candidate 1 in R4C7 negates Row 4 as a Base Set.
@@SudokuSwami Sir I am talking about R4C6 which is "4" So should we consider R4C4 which is "189" as fin.
No. The Candidate 1 in R4C7 is not in the same Column as the Candidate 1 in R1C6. The Cover Sets are Columns 1 & 6. You cannot have any Candidates in Column 7. All Base Candidates must lie in the Cover Sets. If the 1 in R4C7, was NOT there, then your assumption would be correct.
@@SudokuSwami oh oK got it Sir, Thank you
Great thanks for all the hard work. I have gone through all your previous tutorials. You are thorough and structured to clearly explain all the techniques. Sashimi refers to fish (or raw meat) being cut into thin pieces. Could this be the reason to call this pattern the Sashimi X-Wing as it is a fish with one corner cut off with the candidate digit?
Hello Igbert. That's the best explanation I have heard! :-) Thanks for your interest, and for your comment.
Some people equate the term Sashimi with being a "degenerate" fish. They argue that it is not really a Fish Pattern at all, because it is incomplete. But in my opinion, if the eliminations are valid, it doesn't really matter what you call it. I still like your analysis the best.
@@SudokuSwami Sashimi translates literally to "pierced body" or "pierced meat" and that would explain the name.
Swami my question pertains to selection of Sashimi fins as it seems other possibilities exist.
On video example at 21:48, you address candidate 8 as you do . Is the 9 on R2C6 not possible for sashimi, thus making the 8 fin at R2C5? If so, that would eliminate the 8 of the BV 4,8 at R3C6.
Same goes for Sashimi 3 at R1C6 with fins at R1C3/4?
If one can eliminate a candidate of a bivalue cell, that would be more fruitful. Please and thank you!
Hello I am in the process of moving from one country to another. I do not have time to examine your question right now. Please give me a couple of weeks, and I will give you a full explanation and reply, as soon as I am able. Thank you.
@@SudokuSwami much obliged sir....thank you! Good luck with your move!
Hello, at 21:13 ve have candidates 7 on R 3 C79 aren't we suppose to eliminate those too because they SEE also the fins unless they are fins too ?
Yes they see the fins. But eliminations in ANY X-Wing can only occur in the Cover Sets, which in this case are Rows 1 and 6. And the only 7 that is in either Row 1 or Row 6, AND can see the fins, is the 7 in R1C9.
Thank you very much, it's very helpful.
In all X-Wings, Fins (if any) will lie in the Base Sets, and Candidate Eliminations (if any) will lie in the Cover Sets.
So. Should the X-wing exist within two blocks instead of four, it seems to me that it would allow for fins in BOTH base sets, as long as they are in the same block, and the result would be the same: either the wing is true or one of the fins is true. Right?
Fins Can ONLY be in ONE of the Blocks. Let's say your X-Wing lies in Blocks 1 & 3. If the Base Sets are in the Columns, there would only be room for ONE Fin, which would allow for 4 possible eliminations in that same Block. If the Base Sets are in the ROWS, then there would be room for 4 Fins, but only ONE possible elimination. REMEMBER: All eliminated Candidates MUST SEE ALL THE FINS.
And yes, you are right: Either the Wing is True or one of the Fins is True.
@@SudokuSwami Yep, so the possible one elimination then would take place in the cell in-between or beside the x-wing cells in that block. Thank you again, I feel I am getting wiser every day 🙂!
Hmmm hold it. Let us say I have my X-wing in Blocks 1 and 3, and base sets in the Rows. The Block 3 X-wing cells are, say, in R1C7 and R3C7, and Fins in say R1C8 and R3C8. Now, they are all in the same Block, no? Only one of them is true, but any other candidate in that Block would see them all, both the X-wing cells and the Fins.. it seems to me this would allow for max 3 eliminations (R2C7,C8,R9). Regardless of whether there are extra Fins in R1C9 or R3 C9 or not. Because everything happens in one block, the cover set plays no role. Am I missing something here?
What you are forgetting, is that a Candidate can only be eliminated, if it would be eliminated by the X-Wing, if the Fins were NOT there. In your case that could only be in Cell R2C7. A Candidate in any other Cell in that Block would NOT be eliminated by the X-Wing alone. The eliminated Candidate(s) must be False EITHER WAY. That is the reason the technique works.
Great! A question to clear this for me. The fins has to be in the same block, right? They can't be in adjoyning block.
Hope I'm clear. Thanks!
Fins can only occur in ONE Block. If there are Fins in more than one of the Blocks, the technique will not work. Eliminations can only be made in the Block containing the Fins. This is explained multiple times in the Video.
@@SudokuSwami got it. Totally missed this. Your videos are great school and very much appreciated. Wishing you the best!
Thank you. Good luck!
I know now how sashimi works, but I’m not sure if I understand the logic.
So If one of the intersections of the incomplete X-wing is allready filled in with another digit, than I can conclude that in the row or collum where the other digit is standing, that in that row or collum should have been a conjugate pair, and that the conjugate pair of that collum or row can be solved? That’s the logic? Is it that simple?
And if there is an incomplete X-wing with one of the intersections missing I can’t conclude anything unless there is a fin in the block where the missing digit is situated. Than it works the same as a finned X-wing. Correct?
I should have said: “if the canditate of the “X-wing” is missing in one of the intersections of the incomplete X-wing” and not “with one of the intersections missing”
Can you still follow me? 😅
Hello Remy. All your questions are answered in the Video. Please watch it again, and listen carefully to what I am saying, always read the text that I write on each side of the puzzle, watch my demonstrations, and study the Examples. There are 6 Examples of each Type: Finned and Sashimi. Video #11-A has even MORE Examples. Also, if you have a Candidate missing in one of the Base Sets of an X-Wing, and there is no Fin, then you will end up with TWO Naked Singles. Good luck.
Dear friend,
As always, thanks for your quick responce!
You are the the nicest person of all! You have invested a lot of work in this. The only reason you are doing this, is to help others unconditionally. And I can tell you that you are doing a great job!!
You said in your introduction video that solving sudo puzzles reduces the chanches for demention and Alzeimer.
Well, I can tell you that is helps for more conditions.
I am suffering from an Anxiety Disorder, and I found out that solving sudoku puzzles helps me to consentrate and focus. It helps me to cope with my problem. But to a certain point I was suffering with the advanced techniques. it's amazing what you do by making me feel better.
I couldn’t find any logic explontions on the internet untill I found your channel. The way you explain all the techniques is crystal clear!
I am eternally grateful for your efforts!
I posted my question before I sow your examples in the video and before I checked your video #11-A. Next time I will post questions AFTER I have watched all examples and alfter I have seen the additional explained videos.
As always, I have made notes of your lesson.
Below, you will find a copy of my notes. Those are without the screenshots I made.
***
Finned and sashimi X wings
A) FINNED X-WINGS
Take notice that eliminations can only be made in the block where the fin is situated!
The fin is always situated in the collums or rows of the BASE SETS
The BLEU cell is the FIN
1. If the fin is FALSE, then you have a X-wing and the RED CELLS can be eliminated.
2. If the fin is TRUE, then all other candidates in the block can be eliminated, including the RED CELLS.
VERRY IMPORTAND NOTICE!!:
This technique works ONLY if there are 1 or 2 fins in ONE BLOCK on the X-wing!
Now when we look for a verity for the fins , there are TWO posibilities for them to occur:
1. ONE of them is thrue
2. BOTH of them are false
There is no third posibility, becouse they can’t both be true.
1. So when both of them are false, then you have a X-wing and the red cells can be eliminated
2. When one of them is thrue, all other candidates in that block can be eliminated, including the red cells.
B) SASHIMI X WINGS (or finned shamimi)
A SASHIMI is an X-wing with one of the candidates missing in one of the intersections or if one of the intersections is taken by another digit and if there is a fin in the block where the missing or taken cell is situated.
TAKE NOTICE that if one of the cells is taken by another digit, and there is no fin, than you simply have a naked single!
Great! You understand it perfectly now. Good job. :-))
At Time Stamp 8:11, you have just talked about the fin in Blue having two candidates
c1r4,c2r4 in block 4.
Looks to me as if the Red Candidates in C3r5,c4r6 now could be the fin and the blue cells
could be eliminated.
That is what is keeping me from seeing the Fin Fish.
Can you explane why my logic is wrong .
Nobody ever talks about how to validate the correct fin if it's depicted as in Time Stamp 8:11.
Or, I've missed something.
So in block four, why couldn't the rolls be reversed Blue becomes Red and Red becomes blue.
Thanks
Any and all Fins must lie in the Base Sets. The Candidate 5's in the Red Cells DO NOT lie in the Base Sets. The two Base Sets in this diagram at 8:11 are Row 1 & Row 4.
The Red Cells cannot be Fins. The logic will not work.
@@SudokuSwami I agree! Now that I did what you said and took all the lessons starting at lession 1, my next lession is 12 Swordfish. I posted when I was without knowledge, sorry. Your lessons are awesome!!!
Sounds great. Good luck, and if you have any questions about anything, please do not hesitate to ask. :-))
@@SudokuSwami greetings sir! This is the particular point that I believe you do not explicitly and specifically hammer that point home. If one doesn't know how to identify the base set, then the subsequent identification of the fin is very difficult. And then perhaps showing an example as to why a certain candidate might look like a fin but it is not would truly results in understanding and excellent grasp of the topic. Thank you!
On the final example what about the x-wing you'd have if the bottom candidates were blocks 5 and 7 of row 8 with a fin twixt the two? Why pick the Sashimi x-wing over the Finned x-wing? You can't have an x-wing using rows 5 and seven cause you can only have one f'd candidate block, right? Does the Sashimi fin take on the value of the missing candidate and its opposite corner? This is like a naked pair without matching numbers. A naked uneven pair. A Sashimi pair. Just pick a number from the block next to it. A triple is a finned pair... How do you play checkers? I think it's past Stephens' bedtime. iosleepy says my iPhone...
Stephen, your question is so convoluted, vague and unclear, that it is very difficult for me to give you an answer. You need to be a little more precise in your description. But if you are asking about using Row 8 as a Base Set, with Row 2 as the other Base Set, yes, this forms a standard Finned X-Wing. However, it would be pointless, as there are no other Candidate 9's in R7C5 or R9C5 to eliminate. The only productive result, is what is shown in the example; A Sashimi X-Wing with Fins in R5C4 & R5C6, and eliminations in R4C5 & R6C5. :-))
Convoluted, vague and unclear. Love it. I WAS pretty tired. So. Are multiple x-wings something that ever happens or can you stop looking when you find one?
Yes, multiple X-Wings are possible. But let's define "multiple." Of course you could have several X-Wings in a puzzle, each using a different "Fish-Digit." And you could have multiple X-Wings (including Regular, Finned, and Sashimi) on the SAME Fish-Digit Candidate. BUT......and this is a BIG BUT....once you use 4 instances of that Candidate (or 3 with a Sashimi), to form an X-Wing, you will not find another X-Wing that contains those same 4 (or 3) instances of that Candidate. There can be other X-Wings using that Same-Digit Candidate, but they must be completely separate. If you think about it hard enough, you will realize that it would be impossible to use the same Candidate (or Candidates) for more than one X-Wing.
With Sudoku I've learned that if it Can happen it Will happen. 5 blocks each with the same 5 numbers in them, etc. Are you a teacher in real life too Swamiman? OK. Back to lesson 12.
I am a musician.
Support Swami
Hi Swami, I have a question about fins. They only work in the blocks they are located in. Now if one of the fins in the base cell is true then the candidates in the cover cells in the block can be eliminated, I totally agree with that. But if the fins are false then the eliminations are carried out in the block concerned by virtue of the X Wing. So my question is: why (if the X Wing is intact) the eliminations are only made in the cover cells within the block and not the other cover cells? I am sure it is true, but I seem to have missed the demonstration. Thanks!
It is because YOU DON'T KNOW yet, whether the Fins are True or False. So you can ONLY make eliminations that would be valid EITHER WAY. Therefore, you can only eliminate candidates that can SEE ALL THE FINS. You cannot make any deductions about any of the other candidates in the Cover Sets. You can only eliminate Candidates that lie in the same Block as the Fins.
That's the reason! Now that you've explained it seems obvious and one of the foundations of the whole course. Great! Thanks! I am going through the videos again to reinforce and maintain what I have learned! Outstanding course!
Hi i'm just wondering why you didn't eliminate the 5 in row 6 column 1. Thankyou (6.22)
If the Fin in R4C2 was definitely TRUE, THEN you could eliminate that 5 in R6C1. But if the Fin is FALSE, it does NOT tell you anything about the 5 in R6C1. You can only eliminate Candidates that would be False EITHER WAY. This applies ONLY to the two 5's in the Red-Colored Cells, R5C3 & R6C3, in this particular diagram.
Thankyou for the reply. I wasn't thinking hard enough, i understand it now.
Great! Good luck.
If the X wing or finn is true, then why cant all other same numbers that aren't Xwing or finn be eliminated? If the Xwing is true or finn is true?????
IN the box containing the finn.?
ok
Only same-digit Candidates that lie in the Cover Sets can be eliminated, because they would be False either way. You cannot make any deductions about OTHER same-digit Candidates that DO NOT lie in the Cover Sets, even though they may lie in the same Block (box) as the Fin or Fins.
The key word is "OR." Either the Fin is True or it is a valid X-Wing. It is one case, or the other. Not both. So you can only eliminate Candidates that would be False either way, as explained in my first response.
One thing you are apparently forgetting, is that if the Fin is False, resulting in a valid X-Wing, only TWO of the four X-Wing Candidates will be True. One diagonal pair will be True, and the other diagonal pair will be False. This is why you cannot make any other eliminations in the Block with the Fin(s), except for those that lie in one of the Cover Sets.
These are impossible to spot
The language and tone in this video is horrible.
That's bad grammar, my friend. It should be: "The language and tone in this video ARE horrible." Nevertheless, it's so nice of you to post such a friendly, thoughtful, and helpful comment. Thank you.