Well and truly stuck - Can anyone help please?

Advanced methods and approaches for solving Sudoku puzzles

Well and truly stuck - Can anyone help please?

Postby zebedee » Sat May 28, 2005 5:07 pm

I wonder whether any Sudoku fans who are brighter than me might be able to help me with a small clue as to the next step on the Very Hard shown below.

* 4 * * 3 7 2 6 *
1 2 * * * * * 7 3
* 3 7 2 * 8 9 * *
* * * * * 3 * * 6
2 6 * * * * 7 3 4
4 * 3 7 * * * * *
* * 2 5 * 1 3 * *
* 5 * * * * * * 2
* 1 * * 9 2 * 5 *

I've been puzzling over it for days without any joy and I suspect I'm missing something really obvious. Any help would be most gratefully received.

Regards to all.


Zeb
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Postby Animator » Sat May 28, 2005 5:45 pm

There is an X-wing in the number 4.

When you see that, and do all things this X-wing imply (as in, remove candidates from cells), then there will be only one place for the number 4 in box 5.
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Postby Animator » Sat May 28, 2005 5:51 pm

Note though that there is also an X-wing in the numer 6...
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Postby Guest » Sat May 28, 2005 7:00 pm

wat do you mean by an x wing
Guest
 

where is the x-wing?

Postby chipe » Sat May 28, 2005 10:23 pm

How about a hint: what are the 4 verticies of the x-wing?
Thanks
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Postby joolslee » Sat May 28, 2005 11:18 pm

The x-wing of 4's - R3C5/C8 and R7C5/C8
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thanks

Postby chipe » Sun May 29, 2005 12:45 am

thanks joolslee, I see it now, though the 4's x-wing didn't seem to accomplish much. Working with the 6's x-wing (row 3, columns 1 and 5; and row 7, columns 1 and 5) gave better results. Thanks again. ... ...... I finished it.
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Postby zebedee » Sun May 29, 2005 6:10 pm

Many thanks for the X-wings tips Animator. I have now managed to solve the puzzle. The X-wing in the 6s was the most useful hint.

Thanks again.

Zeb
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Posts: 26
Joined: 27 March 2005


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