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		| arkietech 
 
 
 Joined: 31 Jul 2008
 Posts: 1834
 Location: Northwest Arkansas USA
 
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				|  Posted: Mon Feb 27, 2012 1:57 pm    Post subject: au 2/27/12 tough |   |  
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				|  	  | Code: |  	  | *-----------* |...|18.|...|
 |..4|...|7..|
 |2.8|...|.3.|
 |---+---+---|
 |7..|..4|..6|
 |..6|.3.|2..|
 |9..|5..|..3|
 |---+---+---|
 |.6.|...|4.8|
 |..1|...|5..|
 |...|.67|...|
 *-----------*
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		| tlanglet 
 
 
 Joined: 17 Oct 2007
 Posts: 2468
 Location: Northern California Foothills
 
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				|  Posted: Mon Feb 27, 2012 3:53 pm    Post subject: |   |  
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				|  	  | Code: |  	  | *-----------------------------------------------------------* | 6     357   357   | 1     8     235   | 9     245   245   |
 | 15    1359  4     | 6     259   2359  | 7     8     125   |
 | 2     159   8     | 47    47    59    | 6     3     15    |
 |-------------------+-------------------+-------------------|
 | 7     1358  35    | 289   129   4     | 18    59    6     |
 | 1458  1458  6     | 789   3     189   | 2     4579  4579  |
 | 9     148   2     | 5     17    6     | 18    47    3     |
 |-------------------+-------------------+-------------------|
 | 3     6     79    | 29    15    15    | 4     279   8     |
 | 48    2478  1     | 3     249   289   | 5     6     279   |
 | 458   2458  59    | 2489  6     7     | 3     1     29    |
 *-----------------------------------------------------------*
 
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 Two steps:
 
 First, a SdC (24589)b7r9; r9c4<>29, r8c2<>48
 
 which opens up a
 
 xy-wing(79-2)r7c34+r8c2; r8c56<>2
 
 to complete the puzzle.
 
 Ted
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		| tlanglet 
 
 
 Joined: 17 Oct 2007
 Posts: 2468
 Location: Northern California Foothills
 
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				|  Posted: Mon Feb 27, 2012 4:35 pm    Post subject: |   |  
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				| Another perspective of my two step solution is that of a one step  "almost xy-wing". 
 xy-wing(79-2)r7c34+r8c2=LS(48)r8c21-(48=5)r9c1-(5=9=2)r9c39-r7c8=r7c4; r8c56<>2
 
 Ted
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		| arkietech 
 
 
 Joined: 31 Jul 2008
 Posts: 1834
 Location: Northwest Arkansas USA
 
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				|  Posted: Mon Feb 27, 2012 5:14 pm    Post subject: |   |  
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				| Here is a one stepper -- I think 
  	  | Code: |  	  | *-----------------------------------------------------------* | 6     357   357   | 1     8     235   | 9     245   245   |
 | 15    1359  4     | 6     259   2359  | 7     8     125   |
 | 2     159   8     | 47    47    59    | 6     3     15    |
 |-------------------+-------------------+-------------------|
 | 7     1358  35    | 289   129   4     | 18    59    6     |
 | 1458  1458  6     | 789   3     189   | 2     4579  4579  |
 | 9     148   2     | 5     17    6     | 18    47    3     |
 |-------------------+-------------------+-------------------|
 | 3     6    a79    |e2-9   15    15    | 4    d279   8     |
 | 48    2478  1     | 3     249   289   | 5     6     279   |
 | 458   2458 b59    | 2489  6     7     | 3     1    c29    |
 *-----------------------------------------------------------*
 s-wing
 (9)r7c3=(9)r9c3-(9=2)r9c9-(2)r7c8=(2)r7c4 => r7c4<>9
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		| ronk 
 
 
 Joined: 07 May 2006
 Posts: 398
 
 
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				|  Posted: Mon Feb 27, 2012 6:10 pm    Post subject: |   |  
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				| Or keith's favorite, the w-wing: (2=9)r7c4 - (9)r7c3 = (9)r9c3 - (9=2)r9c9 ==> r7c8<>2, ste |  | 
	
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		| SudoQ 
 
 
 Joined: 02 Aug 2011
 Posts: 127
 
 
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				|  Posted: Mon Feb 27, 2012 7:55 pm    Post subject: |   |  
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				| There is also a "crash & burn" solution: 
 r7c4=9 -> r7c3=7 -> .. -> r8c9=79
 
 /SudoQ
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		| Marty R. 
 
 
 Joined: 12 Feb 2006
 Posts: 5770
 Location: Rochester, NY, USA
 
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				|  Posted: Tue Feb 28, 2012 4:36 pm    Post subject: |   |  
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				| I used the 29 W-Wing after staring at the grid forever before seeing it. |  | 
	
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