## Local - Wing

Advanced methods and approaches for solving Sudoku puzzles

### Local - Wing

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. `

aka L3- wing

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+| /  /  / | /  /    / /  .  / | .  .  . | .  .    .------------------------------/  .  / | .  .  . | .  .    . /  .  / | .  .  . | .  .    . /  .  / | .  .  . | .  .    .`
Last edited by StrmCkr on Sat Mar 16, 2019 6:22 am, edited 1 time in total.
Some do, some teach, the rest look it up.

StrmCkr

Posts: 1283
Joined: 05 September 2006

### Re: Local - Wing

Do you have an example?

Keith
keith
2017 Supporter

Posts: 221
Joined: 03 April 2006

### Re: Local - Wing

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
Some do, some teach, the rest look it up.

StrmCkr

Posts: 1283
Joined: 05 September 2006

### Re: Local - Wing

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,

Keith
keith
2017 Supporter

Posts: 221
Joined: 03 April 2006

### Re: Local - Wing

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.
Some do, some teach, the rest look it up.

StrmCkr

Posts: 1283
Joined: 05 September 2006

### Re: Local - Wing

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
-SpAce-: Show
Code: Select all
`   *             |    |               |    |    *        *        |=()=|    /  _  \    |=()=|               *            *    |    |   |-=( )=-|   |    |      *     *                     \  ¯  /                   *    `

"If one is to understand the great mystery, one must study all its aspects, not just the dogmatic narrow view of the Jedi."

SpAce

Posts: 2671
Joined: 22 May 2017

### Re: Local - Wing

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.
Some do, some teach, the rest look it up.

StrmCkr

Posts: 1283
Joined: 05 September 2006