Random Tips & Tricks / Episode 3

[@raycicin1794]

OMG, I would never have figured out any of this on my own. Thank you so much !!

[@gerryandlizkeogh1817]

HI Swami, help please as I've either misunderstood or missed something, at 10 minutes 5 seconds you show the second Sashimi and the fin is at R9C2, and the elimination is in C1R7? The bit I don't understand is why this is not also a fin as both candidates fall between the X wing candidates? I must confess that even though I've watched your videos on Sashimis several times I still get this wrong. I do understand it as the empty rectangle and the skyscraper, but just struggle on the fins! Thank you in advance Gerry

[@SudokuSwami]

This is a peculiar configuration, because several things are going on at the same time. But AS ALWAYS, regardless of how you see it, or which order you apply the techniques, the end result is EXACTLY the same. In terms of a Sashimi X-Wing, there are actually FOUR going on simultaneously. The first thing to remember is that anything you want to call a Fin, must lie in one of the Base Sets. I showed the Base Sets as first being in Rows 5 & 9, with the eliminations as shown in the Video. But there are TWO MORE Sashimi X-Wings if you envision the Base Sets as Columns 1 & 9. In the first case, the Sashimi Cell is R9C1, and the Fin would be R7C1. This would eliminate the 9 in R9C2. In the second case the Sashimi Cell would be R7C9, and the Fin would be R7C7. This would eliminate the 9 in R7C8. There is actually yet another Empty Rectangle as well. See if you can find it! Ha ha. SS

[@gerryandlizkeogh1817]

@@SudokuSwami Thanks Swami, I'm still missing this, I must confess I often have trouble working out which are the fins! if you only see the Sashimi Xwing isn't C1R7 in the base set looking in the columns - vertically? [obviously this is an odd case as the X wing works both ways - vertically and horizontally] again thanks in advance Gerry

[@SudokuSwami]

At 10:05, I am talking about the Base Sets being in the Rows (Rows 5 & 9). If you instead, imagine the Base Sets are in the Columns (1 & 9), The four X-Wing Cells are R5C19 and R9C19. R9C1 is the Sashimi Cell, R7C1 is the Fin, and the 9 would be eliminated from Cell R9C2. Gerry, you should not try to understand Sashimi X-Wings until you fully understand a plain old Finned X-Wing. Please remember that any Fins must occur in the Base Sets. In a Sashimi X-Wing, ONE of the four Candidates in the four Cells of the X-Wing "rectangle" is missing, and you have another instance (or two) of the X-Wing Candidate in the same Block where the Candidate is missing, but any and all Fins must be in that Base Set. When this happens, you can make the same eliminations that you would have obtained from a normal X-Wing, but ONLY in the Block where the Fin or Fins are.

[@DillPicklePatrick]

@@gerryandlizkeogh1817 an entire year late, but to try and simplify this a bit: He found the X-wing on the ROWS 5 and 9, because there was only 2 instances of candidate 9 in both row 5 and row 9, except that in row 9 the second instance of candidate 9 is already taken up by a digit in the cell. If you ignore the digit and pretend candidate 9 is in it, we have an x wing. It is important to note that this X-wing was on ROWS. So rows are now our,” base set”. If you also see an extra candidate 9 in the base set, and only 1, (or 2 if they are in the same block), than you can remove any candidate 9 that lies within the COLUMNS of the X-wing as long as they also see the fin(s). The reason R7C9 is not considered a fin, is because it is not in the same ROW as the X-wing, thus it is not a base set, meaning it can never be a fin.

[@SudokuSwami]

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[@johnnason2203]

I just missed an x-wing and solved a puzzle with two empty rectangles (weird). One would think the x-wing would jump out but it didn't. I ended up using the more advanced technique which was apparent.

[@SudokuSwami]

Ha-ha, great! That happens to me all the time. Sometimes after I solve a puzzle, I will reset it, and solve it again. And many times the second time through, I will end up solving it in a completely different way. I always say, there are several ways to solve any particular puzzle. And it doesn't matter which path you follow, as long as you get the job done. :-)) That's why it is good to learn as many solving techniques as possible, so that that if you miss one thing, you will have a better chance of seeing another.

[@johnnason2203]

I find "difficult" (those that need more than locked candidates) puzzles still very difficult to solve. I'll stare at a puzzle for hours and find nothing. I hope this improves with practice. One time I stared and stared for a long time only find a hidden single was gumming up the works.

[@SudokuSwami]

Do you use candidate filters?

[@johnnason2203]

Yes, I use them and they help quite a bit. I am looking forward to your video on Method of Solving and Basic Strategy. For the way I think, I need process and methodology otherwise I am darting aimlessly around the puzzle.

[@SudokuSwami]

Well, a methodology can be a helpful guide, but at best it will be a generalization that cannot apply to each and every situation or puzzle. It will be a while before I get to making the Video you are referring to. In the meantime, here is a tip. Assess what you are looking at, and proceed accordingly. If there are a lot of Bi-Value Cells, look for XY-Wings, W-Wings, XY-Chains, and Remote Pairs, for instance. And if there are a lot of Conjugate Pairs, look for AIC's and X-Chains, etc. If you are really, really stuck, that's when you need to look for SDC's and Loops. I will cover all these things, in due Course. Producing these Videos is a tedious process, and requires me to mentally rest for a few days in between them. I'm going as fast as I can, my friend! Please be patient and stick with me. :-))

[@affable11]

Waiting eagerly for tutorial #19.

[@SudokuSwami]

Ha-ha. Does this mean you have already watched ALL of my other Videos, and have mastered ALL the principles described therein? :-)

[@mirekt1822]

not only affable11. Me too ;-)

[@SudokuSwami]

Okay, okay you guys! I appreciate your enthusiasm. It was a lot of work to get the Random Tips Series and the SPEED Course going. It was a whirlwind effort. So I needed a little break. But now I plan to get back to the Main Course. I will try to get the next three Tutorials done in the next two weeks. Stay tuned. And thanks for your support.

[@affable11]

Sudoku Swami God Bless You. Thank You.

[@gerryandlizkeogh1817]

@@affable11 ditto!