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		| George Woods 
 
 
 Joined: 28 Mar 2006
 Posts: 304
 Location: Dorset UK
 
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				|  Posted: Tue Aug 09, 2016 9:10 am    Post subject: Aug 9 V Hard |   |  
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				| It's not my role to be first with a solution but nevertheless here it is. Having done fundamentals to the critical point A W Wing 23 operating on 2s in row 7 so r8c3 becomes 3 |  | 
	
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		| hughwill 
 
 
 Joined: 05 Apr 2010
 Posts: 424
 Location: Birmingham UK
 
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				|  Posted: Tue Aug 09, 2016 9:25 am    Post subject: |   |  
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				|  	  | Code: |  	  | +-----------+------------+------------+
 | 58  6 9   | 7  18  158 | 3   2  4   |
 | 1   3 4   | 26 26  58  | 58  9  7   |
 | 258 7 28  | 3  4   9   | 158 6  158 |
 +-----------+------------+------------+
 | 6   9 7   | 5  3   4   | 28  1  28  |
 | 3   8 5   | 1  7   2   | 6   4  9   |
 | 4   2 1   | 8  9   6   | 57  37 35  |
 +-----------+------------+------------+
 | 28  4 6   | 9  5   38  | 127 37 123 |
 | 7   5 23  | 4  12  13  | 9   8  6   |
 | 9   1 238 | 26 268 7   | 4   5  23  |
 +-----------+------------+------------+
 
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 Play this puzzle online at the Daily Sudoku site
 
 
  	  | Quote: |  	  | It's not my role to be first with a solution but nevertheless here it is. Having done fundamentals to the critical point A W Wing 23 operating on 2s in row 7 so r8c3 becomes 3 | 
 
 (As always) nice solution George. But is it a W wing? Any way my conventional
 solution: 28-3 XY-wing is a bit anaemic in comparison!
 
 Hugh
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		| George Woods 
 
 
 Joined: 28 Mar 2006
 Posts: 304
 Location: Dorset UK
 
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				|  Posted: Tue Aug 09, 2016 9:45 am    Post subject: w wings |   |  
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				|  	  | Quote: |  	  | But is it a W wing? 
 A w wing has been described as .... strong link... The strong link is sufficient but not necessary. The full logic (in the context of this one) is the two 23s cannot both be 2 because if they were there would be no 2 in row 7 so at least one of the wings must be 3 ......
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		| Marty R. 
 
 
 Joined: 12 Feb 2006
 Posts: 5770
 Location: Rochester, NY, USA
 
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				|  Posted: Tue Aug 09, 2016 12:27 pm    Post subject: |   |  
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				| Yes, it's a W-Wing. Maybe the 2s in r7 don't look like a conventional strong link, but they form a grouped strong link. And George's logic, while correct, is not necessary since the direct elimination (-3r9c3) from the wing is all that's needed. 
 As is not unusual, I messed up the puzzle due to incorrect basics and used two X-wings before the XY-Wing appeared.
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