Local - Wing

Advanced methods and approaches for solving Sudoku puzzles

Local - Wing

Postby StrmCkr » Thu May 10, 2018 7:45 am

this techniques been around for a number of years on Dailysudoku

Code: Select all
{Local wing} L-WING x=(x-y)=(y-z)=z  z may be eliminated from the beginning cell and x can be eliminated from the ending cell.


i will note it has 100% overlap with hybrid wings:

however both names have been out for a number of years and I wont dispute either claims to first, this post is here mostly for posterity on the move set.

Code: Select all
H1-Wing:  (X)a = (X   -  Y)b = (Y-Z)c = (Z)d     "a" and "d" in same unit; a<>Z, d<>X


Code: Select all
 L- wing
.  /  . | .  /  . | .  .    .
. A-C . | . C-A . | .  .    .
.  /  . | .  /  . | .  .    .
------------------------------
.  /  . | .  /  . | .  .    .
/ AB+ / | / BC+ / | /  /    /
.  /  . | .  /  . | .  .    .
------------------------------
.  /  . | .  /  . | .  .    .
.  /  . | .  /  . | .  .    .
.  /  . | .  /  . | .  .    .


Code: Select all
L- wing
A  .  / | .  .  . | .  .    .
A  . C-A| .  .  . | .  .    .
A  .  / | .  .  . | .  .    .
------------------------------
/  .  / | .  .  . | .  .    .
AB+/ BC+| /  /  / | /  /    /
/  .  / | .  .  . | .  .    .
------------------------------
/  .  / | .  .  . | .  .    .
/  .  / | .  .  . | .  .    .
/  .  / | .  .  . | .  .    .
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Re: Local - Wing

Postby keith » Wed May 16, 2018 1:52 pm

Do you have an example?

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Re: Local - Wing

Postby StrmCkr » Wed May 16, 2018 4:39 pm

Code: Select all
    +-------------------+--------------------+----------------------+
     |  37    9    457   |  1     6      34   | d457-2 a28   24578   |
     |  2     46   467   |  8     9      5    |  1      3    47      |
     |  13    8    145   |  7     2      34   |  45     9    6       |
     +-------------------+--------------------+----------------------+
     |  568   46   2     |  34    348    9    | c567    1    57      |
     |  59    1    3     |  6     7      2    |  8      4    59      |
     |  689   7    468   |  5     148    18   |  3     b26   29      |
     +-------------------+--------------------+----------------------+
     |  4     23   168   |  39    5      18   |  269    7    128     |
     |  168   5    9     |  2     148    7    |  46     68   3       |
     |  178   23   178   |  349   1348   6    |  249    5    1248    |
     +-------------------+--------------------+----------------------+


L-wing (2)r1c8 = (2-6)r6c8 = (6-7)r4c7 = (7)r1c7 => -2 r1c7; lclste
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Re: Local - Wing

Postby keith » Wed May 16, 2018 10:40 pm

StrmCkr

This is just my opinion, take it for what it's worth.

I have seen these creatures many times, though I have never discovered one myself. How to look for them? They require stringing together 3 Single-Digit Strong Links for three different digits. The pencil marks really do not provide any clue as to how to recognize the pattern.

I suspect that every one that posts these patterns is using computer software to find them. That's not much use to armchair pencil and paper solvers like me. That said, I believe these are quite common.

Best wishes,

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Re: Local - Wing

Postby StrmCkr » Thu May 17, 2018 1:22 am

Yes, it's three strong links on 3 different digits with an over lap in one sector.

The easiest approach to finding them is

looking for the middle sector which is always a Bi-local. { digit filer}
next step is checking if another digit is strong linked at one of the bi-local points, {2nd digit filter}
repeat for the other point. {3rd digit filter}

For the above example it's the box 6 on digit 6. one end point has a 7, the other side has 2.

if end points of 2 & 7 are peers, perform eliminations.

pen/paper solving has several different ways to mark pm's here is one i used for a long time.

i used to mimic digit filters by individually mapping out each Digit on a clear erasable marker sheets {1 digit per page}
{all pm's represented clearly by overlapping the sheets.}

find a sector with 2 digits circle it then cycle the remaining 7 sheets to see which one also has a overlapping strong link. circle that sector.
then cycle the remaining 6 sheets to find another overlap on the opposite side circle it.

then compare sheet 2 and 3 for same sector peers. then erase eliminations off the applicable page.

with out the 9 sheets: i just write down the digits with strong links for pm's only.
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Re: Local - Wing

Postby SpAce » Wed Jun 20, 2018 12:26 am

Seems like a special case of Hodoku AIC Type 2. I guess it's the shortest of such chain to make it a "wing". Correct?

http://hodoku.sourceforge.net/en/tech_chains.php#nl4
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Re: Local - Wing

Postby StrmCkr » Wed Jun 20, 2018 2:49 pm

Yes, the idea when most of these came out was to have a. Collection of simple short chains with 3-4 links on 2-3 digits for easy usage for manual players and short programing functions on top of a generalized function.

Other wise: w, m, s, IW, l, l2, h wings wouldnt exsit on their own as they are all nice loops/AIC

Same thing can be said for xy, xyz, Wxyz,... As these are simplified als-xz rules.
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