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		Clement
 
 
  Joined: 24 Apr 2006 Posts: 1113 Location: Dar es Salaam Tanzania
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				 Posted: Mon Aug 30, 2010 10:56 pm    Post subject: Aug 31 VH | 
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				Two steps(XY-Wings):-
 
1) XY-Wing 14 16 46 Pivoted in r9c1 removes 4 in r4c4 opens another
 
2) XY-Wing 67 47 46 with Pivot in r1c1 eliminating 6 in r7c6 solving the puzzle. | 
			 
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		Marty R.
 
 
  Joined: 12 Feb 2006 Posts: 5770 Location: Rochester, NY, USA
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				 Posted: Tue Aug 31, 2010 4:18 am    Post subject:  | 
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				I would probably not have used this DP had Nataraj not posted his very similar DP here just today:
 
 
http://www.dailysudoku.co.uk/sudoku/forums/viewtopic.php?t=5035
 
 
Here's my grid after basics:
 
 
 	  | Code: | 	 		  
 
+-------------+-------------+---------+
 
| 478  1  3   | 4678 48  46 | 2  9 5  |
 
| 89   6  2   | 5    19  3  | 18 4 7  |
 
| 4789 5  47  | 478  19  2  | 6  3 18 |
 
+-------------+-------------+---------+
 
| 14   9  145 | 48   458 7  | 3  2 6  |
 
| 2    8  46  | 3    46  1  | 7  5 9  |
 
| 3    7  56  | 2    56  9  | 48 1 48 |
 
+-------------+-------------+---------+
 
| 67   34 9   | 1    27  46 | 5  8 23 |
 
| 5    34 17  | 9    27  8  | 14 6 23 |
 
| 16   2  8   | 46   3   5  | 9  7 14 |
 
+-------------+-------------+---------+
 
 | 	  
 
Play this puzzle online at the Daily Sudoku site
 
 
There is a potential DP 45-46-56 in r456, c35. The DP can be broken up by the 8 in r4c5 or the 1 in r4c3. The 8 proves a 1 in r9c1 and this acts as a pincer with the 1 in r4c3, eliminating 1s in boxes 47, solving the puzzle. | 
			 
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		kuskey
 
 
  Joined: 10 Dec 2008 Posts: 141 Location: Pembroke, NH
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				 Posted: Tue Aug 31, 2010 4:34 am    Post subject: 31 Aug VH | 
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				| I agree with Clement but would add that the 467 xy-wing can be played two ways;with the pivot at r1c1 eliminating 6 in r7c6, or with the pivot at r7c1 eliminating 4 at r1c6 - somewhat unusual, I think. | 
			 
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		Clement
 
 
  Joined: 24 Apr 2006 Posts: 1113 Location: Dar es Salaam Tanzania
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				 Posted: Tue Aug 31, 2010 7:02 pm    Post subject: Aug 31 VH | 
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				Kuskey,
 
It is quite O.K. It occurs several times for the same configuration in an XY wing to have different pivots. I did not notice that one. | 
			 
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		storm_norm
 
 
  Joined: 18 Oct 2007 Posts: 1741
 
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				 Posted: Tue Aug 31, 2010 8:00 pm    Post subject:  | 
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				this is Marty's brilliant find.
 
 
 
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		Marty R.
 
 
  Joined: 12 Feb 2006 Posts: 5770 Location: Rochester, NY, USA
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				 Posted: Tue Aug 31, 2010 9:27 pm    Post subject:  | 
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				 	  | Quote: | 	 		  | this is Marty's brilliant find.  | 	  
 
Thanks very much, but most of the credit should probably go to Nataraj. | 
			 
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		Luke451
 
 
  Joined: 20 Apr 2008 Posts: 310 Location: Southern Northern California
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				 Posted: Wed Sep 01, 2010 1:53 pm    Post subject:  | 
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				It has been interesting to watch the emergence of BUG-Lite use lately. With Marty's find, along with Nataraj's and  Keith's last month,  we'll have to retire the "rare" label soon    .
 
 
Since this BUG-Lite provides the strong link (1)r4c3=(8)r4c5, I would express it as an AIC.
 
 	  | Code: | 	 		   *-----------------------------------------------------------*
 
 | 478   1     3     | 4678  48    46    | 2     9     5     |
 
 | 89    6     2     | 5     19    3     | 18    4     7     |
 
 | 4789  5     47    | 478   19    2     | 6     3     18    |
 
 |-------------------+-------------------+-------------------|
 
 | 14    9     145   | 48    458   7     | 3     2     6     |
 
 | 2     8     46    | 3     46    1     | 7     5     9     |
 
 | 3     7     56    | 2     56    9     | 48    1     48    |
 
 |-------------------+-------------------+-------------------|
 
 | 67    34    9     | 1     27    46    | 5     8     23    |
 
 | 5     34    17    | 9     27    8     | 14    6     23    |
 
 | 16    2     8     | 46    3     5     | 9     7     14    |
 
 *-----------------------------------------------------------*
 
 
(1)r4c3=(8)r4c5-(8=4)r4c4-(4=6)r9c4-(6=1)r9c1 =>r4c1<>1 | 	 
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		sheryl
 
 
  Joined: 24 Sep 2007 Posts: 64 Location: New York
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				 Posted: Wed Sep 01, 2010 2:39 pm    Post subject: where are the xy wings | 
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				clement,
 
can you please specify row and columns for the first 14, 16, 46 xy wing.  i have all those numbers but they don't form an xy wing for me. | 
			 
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		Marty R.
 
 
  Joined: 12 Feb 2006 Posts: 5770 Location: Rochester, NY, USA
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				 Posted: Wed Sep 01, 2010 3:57 pm    Post subject: Re: where are the xy wings | 
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				 	  | sheryl wrote: | 	 		  clement,
 
can you please specify row and columns for the first 14, 16, 46 xy wing.  i have all those numbers but they don't form an xy wing for me. | 	  
 
I'm not Clement, but check the grid immediately above your post. The pivot (16) is in r9c1 and the others (14,46) are in r4c1 and r9c4. | 
			 
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		sheryl
 
 
  Joined: 24 Sep 2007 Posts: 64 Location: New York
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				 Posted: Wed Sep 01, 2010 4:21 pm    Post subject: thank you | 
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				it was right in front of me   | 
			 
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