XYZ wing...a question

Advanced methods and approaches for solving Sudoku puzzles

XYZ wing...a question

Postby Luke » Tue Aug 15, 2006 4:25 am

First of all, I'm new at this crazy game. How'd I get roped into this, anyway??? Oh, yeah. I did it to myself, go figger.

What I know of this technique comes from Scanraid,
http://www.scanraid.com/AdvanStrategies.htm#XYZ

The Scanraid web page shows only the "hinge" square as containing all three of the possible candidates, or XYZ. The other squares contain only XZ and YZ.

Today I found a puzzle in which the "hinge" candidates were duplicated in one of the arms, all three. My question is, with this technique can you have more than two candidates in the "outer cells?" In this case, it allowed me to eliminate 2 candidates instead of just one.

Here's the germaine portion of the puzzle:

* | * | * || * | * | * ||12379| 5 | 139 ||
* | * | * || * | * | * || 46 | 27 | 46 ||
127 | 4 | 39 || 27 | 56 | 56 ||12379| 8 | 139 ||

The "pivot" square is R3C9 (139). The "outer" cells are R3C3 (39) and R1C9 (139 again). It seems to me that there exists no scenario in which R3C7 can contain 3 or 9, since all three cells can "see" the contents of R3C7.

In most XYZ wings the outer cells have only 2 candidates. In other words,
R1C9 would have only the candidates 13 or 19, not 139. I have never seen an example like I've shown here on any web page.

Am I missing something?

Luke in Ca
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Postby RW » Tue Aug 15, 2006 7:42 am

Luke451 wrote:
Code: Select all
*   | * | *  || *  | *  | *  ||12379| 5  | 139 ||
*   | * | *  || *  | *  | *  || 46  | 27 | 46  ||
127 | 4 | 39 || 27 | 56 | 56 ||12379| 8  | 139 ||


The "pivot" square is R3C9 (139). The "outer" cells are R3C3 (39) and R1C9 (139 again). It seems to me that there exists no scenario in which R3C7 can contain 3 or 9, since all three cells can "see" the contents of R3C7.


How about:
Code: Select all
.  .  .  |  .  .  .  |  27 5  9
.  .  .  |  .  .  .  |  46 27 46
27 4  9  |  27 56 56 |  3  8  1

or

.  .  .  |  .  .  .  |  27 5  3
.  .  .  |  .  .  .  |  46 27 46
27 4  3  |  27 56 56 |  9  8  1


RW
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Postby Luke » Wed Aug 16, 2006 2:16 am

Thanks for straightening me out. I went back and took another look.
I got fooled by the fact that luckily the result I got turned out to be right.

On a side note: how does one go abt placing "code" in a window in a post on this site? I see the code button but I don't know how to use it.

Thanks for helping me get up to speed.

Luke in Ca
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Location: Southern Northern California

Postby emm » Wed Aug 16, 2006 4:02 am

Hi Luke in Ca

Type in the text or grid in the reply box

Use the mouse to highlight the part you want in the code box and click the code button

You need to preview before you submit to make sure its aligned

Bold and quote buttons work in the same way
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