rjamil wrote:By looking "Y wing style example 1", is it also called XY-Wing Hybrid move?
No. It's an L3-Wing. SteveK's "Y-Wing Styles" simply include the various one-letter-wings (Y,W,H,M,S,L) that have three strong links in different configurations. (Apparently the XYZ-Wing is also included, though its membership is based on a bit wider interpretation.) I guess those other wings besides the Y-Wing (i.e. XY-Wing) didn't have specific names back then, or SteveK wasn't aware of them, so he invented his own (somewhat confusing) collective name based on the only named pattern in the group. I think we should consider that name ("Y-Wing Styles") obsolete, while at the same time recognize SteveK's brilliance in seeing how all of those patterns fit into the same family. (I bet he was one of the first, if not the first to make that observation.)
Here's the pattern in question presented as a chain (first using SteveK's chess coordinates, and then the rYcX used here):
(1)a1 = (1-3)i1 = (3-2)g3 = (2)a3 => a3 <> 1, a1 <> 2
(1)r9c1 = (1-3)r9c9 = (3-2)r7c7 = (2)r7c1 => -1 r7c1, -2 r9c1
Clearly an L3-Wing. The other patterns on that
same page are XYZ-Wing, Grouped M-Ring, and Grouped W-Wing.
However,
JSudoku site gives alias W-Wing alias Semi Remote Pair.
Like I said, W-Wing is
one example of SteveK's "Y-Wing Styles" patterns, not an alias for it. It just might be the most common one, or at least the easiest to spot. Looks like SteveK started calling it W-Wing himself
here. ("Semi Remote Pair" is actually a very descriptive name for W-Wing, but no one (at least here) uses it, so you shouldn't either.) Also, Y-Wing is an alias for XY-Wing, not for W-Wing!! Thus this is completely false:
JSudoku wrote:A Y-Wing is a simple pattern formed by a strong link and two cells with two same candidates.
Should obviously be W-Wing. Looks like the JSudoku author had completely misunderstood SteveK's "Y-Wing Styles" idea and thought it only meant W-Wings.
Am I interpreting right way in below mentioned exemplars form?
Doesn't look like it at all, I'm afraid. It's not totally your fault, though. SteveK has some truly brilliant stuff in his blog, but a lot of it is hard to understand because of the peculiar naming, notation, and coordinate systems. That's why even common patterns can be somewhat hard to recognize. Even I still have to rewrite a lot of his stuff into a language that is easier to read for me, and I'm quite fluent in almost every sudoku notation there is.
That's why I kind of doubt it's the right place for you to dig into at the moment, to be honest. I'm repeating myself, once again, but you'd be better off learning the fundamentals of chaining first (SteveK does have good stuff on chaining too, being a fan of AICs, but it's just notated a bit differently). To really understand SteveK's stuff one should learn to read
his matrices as well (that was the hardest part and the most recent acquisition for me, but well worth it). Otherwise you'll be likely to confuse yourself, like you just did.
PS. On the
Finding Y Wing Styles page you'll find the general descriptions of each type in terms of strong link configurations and numbers of digits, which correspond directly with the one-letter-wings:
- Code: Select all
1. 3 strong cells, 3 total digits : Y-Wing / XYZ-Wing : VVV / V[V]V
2. 2 strong cells, 1 strength in location (house), 2 total digits : W-Wing : VLV
3. 2 strong cells, 1 strength in location, 3 total digits : H3-Wing : VVL
4. 1 strong cell, 2 strengths in location, 2 total digits : M-Wing / S-Wing : VLL / LVL
5. 1 strong cell, 2 strengths in location, 3 total digits : H2-Wing : VLL
6. 3 strengths in location, 1 digit : X-Chain (L1-Wing) : LLL
7. 3 strengths in location, 2 digits : L2-Wing : LLL
8. 3 strengths in location, 3 digits : L3-Wing : LLL
(Note that I've replaced "candidates" with "digits" and added the corresponding wing-names and strong-link configurations.)
Last but not least, one bit of wisdom from the same source:
SteveK wrote:I hate to name techniques, as they are all really just forbidding chains [i.e. AICs].
I couldn't agree more. There's no real need to know patterns and their names, except for easier communication.