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May 31 VH

 
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Earl



Joined: 30 May 2007
Posts: 677
Location: Victoria, KS
PostPosted: Sun May 31, 2009 1:44 am    Post subject: May 31 VH Reply with quote
It's high time we had a VH.

A TOWERING SOLUTION: a skyscraper <8> clears the path.

Early Earl
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storm_norm



Joined: 18 Oct 2007
Posts: 1741
PostPosted: Sun May 31, 2009 3:32 am    Post subject: Reply with quote
Quote:
It's high time we had a VH.

Earl,
May I remind you that Danny posts Very Hard puzzles in his forum everyday?

Last edited by storm_norm on Sun May 31, 2009 5:35 am; edited 1 time in total
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Marty R.



Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
PostPosted: Sun May 31, 2009 4:45 am    Post subject: Reply with quote
A W-Wing on 89 does it too. I'll echo Norm's suggestion to take a look at Danny's puzzles.
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crunched



Joined: 05 Feb 2008
Posts: 168
PostPosted: Sun May 31, 2009 7:18 am    Post subject: Reply with quote
An x-y wing does it.
Below (all?) is stripped to the basics.
Code:

+-------------+-----------------+---------------+
| 9   4  1    | 357  23567  236 | 236 278 2378  |
| 37  5  8    | 37   26     9   | 26  4   1     |
| 37  6  2    | 1    4      8   | 9   57  357   |
+-------------+-----------------+---------------+
| 1   7  59   | 6    89     4   | 25  3   258   |
| 6   89 359  | 2    389    7   | 1   58  4     |
| 48  2  34   | 38   1      5   | 7   9   6     |
+-------------+-----------------+---------------+
| 58  1  6    | 9    23578  23  | 4   257 2357  |
| 2   3  579  | 4    57     1   | 8   6   579   |
| 458 89 4579 | 3578 235678 236 | 235 1   23579 |
+-------------+-----------------+---------------+

Play this puzzle online at the Daily Sudoku site
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Clement



Joined: 24 Apr 2006
Posts: 1111
Location: Dar es Salaam Tanzania
PostPosted: Sun May 31, 2009 10:50 am    Post subject: Daily Sudoku: Sun 31-May-2009 VH Reply with quote
Finned X-Wing on 8 solves the puzzle.
There is a potential X-Wing on 8 in columns 1&4 i.e r69c14. The fin rule allows us to remove the 8 in r9c2 because, it shares the same unit (BOX) as the fin cell in r7c1.
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Earl



Joined: 30 May 2007
Posts: 677
Location: Victoria, KS
PostPosted: Sun May 31, 2009 3:39 pm    Post subject: May 31 VH Reply with quote
"It's high time we had a VH" is a pun on the solution technique, a skyscraper.

Am I too subtle or too dense?

Earl

Last edited by Earl on Mon Jun 01, 2009 4:41 pm; edited 1 time in total
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gindaani



Joined: 06 Mar 2009
Posts: 79
PostPosted: Mon Jun 01, 2009 1:06 am    Post subject: Reply with quote
The typical xy-wing is all it took for me. An 895 xy-wing for this one.

(I've taken to listing the pivot first in my xy-wing designations. So in this case 89 is the pivot. I think it makes them easier to spot.)
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keith



Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
PostPosted: Mon Jun 01, 2009 2:49 am    Post subject: Reply with quote
gindaani wrote:
The typical xy-wing is all it took for me. An 895 xy-wing for this one.

(I've taken to listing the pivot first in my xy-wing designations. So in this case 89 is the pivot. I think it makes them easier to spot.)


Or, you could say -589 where the - precedes the pincer candidate in any chain.

Keith
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Sue



Joined: 06 Jan 2008
Posts: 6
Location: Adelaide
PostPosted: Sun Jun 07, 2009 4:38 am    Post subject: anyone can help to clarify Reply with quote
Dear posters,

I have got my puzzle to the bare bones as shown above, and have read the discussion here, studied xy wings and skyscrapers, but am not sure how to go ahead with it. Has anyone got the time to point out how the next steps would work?

thanks, sue
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Marty R.



Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
PostPosted: Sun Jun 07, 2009 5:16 am    Post subject: Reply with quote
Sue,

If you've studied XY-Wings, then you know the basic rule. We start with a cell we call XY. That cell must see both an XZ and a YZ, then any cell that can see both XZ and YZ cannot contain Z. Our XY is the 89 in r5c2. The XZ is the 58 in r5c8 and the YZ is the 59 in r4c3. Thus, obviously, the Z is 5. Both r5c3 and r4c9 see both the XZ (58) and YZ (59), thus neither cell may contain Z (5).

Hope this helps.
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crunched



Joined: 05 Feb 2008
Posts: 168
PostPosted: Sun Jun 07, 2009 5:33 am    Post subject: Re: anyone can help to clarify Reply with quote
Sue wrote:
Dear posters,

I have got my puzzle to the bare bones as shown above, and have read the discussion here, studied xy wings and skyscrapers, but am not sure how to go ahead with it. Has anyone got the time to point out how the next steps would work?

thanks, sue


There is a star beside each of the xy pairs (89 59 58 ). The 89 is called the pivot. The 58 and the 59 are the "pincers" each containing a 5. They both "see" or touch the 5 in the cell with 25 and the cell with 258 in row 4 (marked with #). This removes those fives in the cells marked by #. One could also say that 58 and 59 are 2 wings stemming from the 89 cell, and that any number that is the same as the number that the wings have in common (5 in this case) can be brushed away.

Code:

+-------------+-----------------+---------------+
| 9   4  1    | 357  23567  236 | 236 278 2378  |
| 37  5  8    | 37   26     9   | 26  4   1     |
| 37  6  2    | 1    4      8   | 9   57  357   |
+-------------+-----------------+---------------+
| 1   7 *59   | 6    89     4   |#25  3  #258   |
| 6  *89 359  | 2    389    7   | 1  *58  4     |
| 48  2  34   | 38   1      5   | 7   9   6     |
+-------------+-----------------+---------------+
| 58  1  6    | 9    23578  23  | 4   257 2357  |
| 2   3  579  | 4    57     1   | 8   6   579   |
| 458 89 4579 | 3578 235678 236 | 235 1   23579 |
+-------------+-----------------+---------------+

Play this puzzle online at the Daily Sudoku site[/quote]
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Sue



Joined: 06 Jan 2008
Posts: 6
Location: Adelaide
PostPosted: Sun Jun 07, 2009 5:41 am    Post subject: Reply with quote
Got it!

thats brilliant, thank you both of you
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Sue



Joined: 06 Jan 2008
Posts: 6
Location: Adelaide
PostPosted: Sun Jun 07, 2009 5:48 am    Post subject: Reply with quote
I am looking at it again, and it seems that 58 can also be the pivot, and pince out the 9 in row5 column 3
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Sue



Joined: 06 Jan 2008
Posts: 6
Location: Adelaide
PostPosted: Sun Jun 07, 2009 5:50 am    Post subject: Reply with quote
Ha! I'm wrong. Duh
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