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		| ZeroAssoluto 
 
 
 Joined: 05 Feb 2017
 Posts: 1019
 Location: Rimini, Italy
 
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				|  Posted: Tue Aug 22, 2017 10:21 pm    Post subject: Aug 23 VH |   |  
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				| Hi everyone, 
 
  	  | Code: |  	  | +-----------+------------+--------------+
 | 146 12  5 | 67 9   167 | 3  8    1246 |
 | 146 8   7 | 5  3   2   | 16 146  9    |
 | 169 129 3 | 4  168 168 | 7  5    126  |
 +-----------+------------+--------------+
 | 3   5   2 | 9  4   16  | 8  16   7    |
 | 7   4   9 | 8  16  3   | 16 2    5    |
 | 8   6   1 | 2  7   5   | 9  34   34   |
 +-----------+------------+--------------+
 | 5   17  6 | 3  2   9   | 4  17   8    |
 | 2   79  4 | 1  68  678 | 5  3679 36   |
 | 19  3   8 | 67 5   4   | 2  1679 16   |
 +-----------+------------+--------------+
 
 | 
 Play this puzzle online at the Daily Sudoku site
 
 
  	  | Quote: |  	  | Sashimi X-Wing with number 1 in r29c19 + r1c9 and -1 in r2c7 | 
 
 Ciao Gianni
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		| Marty R. 
 
 
 Joined: 12 Feb 2006
 Posts: 5770
 Location: Rochester, NY, USA
 
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				|  Posted: Wed Aug 23, 2017 5:11 am    Post subject: Re: Aug 23 VH |   |  
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				|  	  | ZeroAssoluto wrote: |  	  | Hi everyone, 
 
  	  | Code: |  	  | +-----------+------------+--------------+
 | 146 12  5 | 67 9   167 | 3  8    1246 |
 | 146 8   7 | 5  3   2   | 16 146  9    |
 | 169 129 3 | 4  168 168 | 7  5    126  |
 +-----------+------------+--------------+
 | 3   5   2 | 9  4   16  | 8  16   7    |
 | 7   4   9 | 8  16  3   | 16 2    5    |
 | 8   6   1 | 2  7   5   | 9  34   34   |
 +-----------+------------+--------------+
 | 5   17  6 | 3  2   9   | 4  17   8    |
 | 2   79  4 | 1  68  678 | 5  3679 36   |
 | 19  3   8 | 67 5   4   | 2  1679 16   |
 +-----------+------------+--------------+
 
 | 
 Play this puzzle online at the Daily Sudoku site
 
 
  	  | Quote: |  	  | Sashimi X-Wing with number 1 in r29c19 + r1c9 and -1 in r2c7 | 
 
 Ciao Gianni
 | 
 
 Gianni,
 
 I'm very confused, which is nothing new. In r2 I see 1s in c178; in r9 I see 1s in c189. Am I misinterpreting what you wrote?
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		| JC Van Hay 
 
 
 Joined: 13 Jun 2010
 Posts: 494
 Location: Charleroi, Belgium
 
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				|  Posted: Wed Aug 23, 2017 5:51 am    Post subject: |   |  
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				| Only 1r7c2 [1r3c9] belongs [doesn't belong] to all the solutions of the 1s; stte 
 Interpretation :
 Grouped Kite {1R2, 1C9} -> -1r9c1; r7c2=1 and stte
 [Skyscraper {1C57} -> -1r3c9]
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		| ZeroAssoluto 
 
 
 Joined: 05 Feb 2017
 Posts: 1019
 Location: Rimini, Italy
 
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				|  Posted: Wed Aug 23, 2017 6:52 am    Post subject: |   |  
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				| Hi Marty, 
 I make confusion
 In the situation of the scheme I used an XY-Wing 1,6,7 in r7c8, r9c49 and -7 in r9c8;
 which brings me to this situation where I used the Sashimi X-Wing
 
 
  	  | Code: |  	  | +---------+---------+-----------+
 | 4  12 5 | 6 9  7  | 3  8   12 |
 | 16 8  7 | 5 3  2  | 16 4   9  |
 | 69 29 3 | 4 18 18 | 7  5   26 |
 +---------+---------+-----------+
 | 3  5  2 | 9 4  16 | 8  16  7  |
 | 7  4  9 | 8 16 3  | 16 2   5  |
 | 8  6  1 | 2 7  5  | 9  3   4  |
 +---------+---------+-----------+
 | 5  17 6 | 3 2  9  | 4  17  8  |
 | 2  79 4 | 1 68 68 | 5  79  3  |
 | 19 3  8 | 7 5  4  | 2  169 16 |
 +---------+---------+-----------+
 
 | 
 Play this puzzle online at the Daily Sudoku site
 
 excuse me
 Ciao Gianni
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		| Clement 
 
 
 Joined: 24 Apr 2006
 Posts: 1113
 Location: Dar es Salaam Tanzania
 
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				|  Posted: Wed Aug 23, 2017 7:43 am    Post subject: Aug 23 VH |   |  
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				|  	  | Code: |  	  | +-----------+-----------+--------------+
 | 146 12  5 | 67 9  167 | 3  8    1246 |
 | 146 8   7 | 5  3  2   | 16 146  9    |
 | 169 129 3 | 4  16 8   | 7  5    12   |
 +-----------+-----------+--------------+
 | 3   5   2 | 9  4  16  | 8  16   7    |
 | 7   4   9 | 8  16 3   | 16 2    5    |
 | 8   6   1 | 2  7  5   | 9  34   34   |
 +-----------+-----------+--------------+
 | 5   17  6 | 3  2  9   | 4  17   8    |
 | 2   79  4 | 1  8  67  | 5  3679 36   |
 | 19  3   8 | 67 5  4   | 2  169-7 16  |
 +-----------+-----------+--------------+
 
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 XY-Wing 16-7 pivoted in r9c9 solves it, 7 is strongly linked in r9
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		| JC Van Hay 
 
 
 Joined: 13 Jun 2010
 Posts: 494
 Location: Charleroi, Belgium
 
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				|  Posted: Wed Aug 23, 2017 8:30 am    Post subject: |   |  
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				| r3c8=r8c5=8  |  | 
	
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		| hughwill 
 
 
 Joined: 05 Apr 2010
 Posts: 424
 Location: Birmingham UK
 
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				|  Posted: Wed Aug 23, 2017 9:09 am    Post subject: Re: Aug 23 VH |   |  
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				|  	  | Clement wrote: |  	  |  	  | Code: |  	  | +-----------+-----------+--------------+
 | 146 12  5 | 67 9  167 | 3  8    1246 |
 | 146 8   7 | 5  3  2   | 16 146  9    |
 | 169 129 3 | 4  16 8   | 7  5    12   |
 +-----------+-----------+--------------+
 | 3   5   2 | 9  4  16  | 8  16   7    |
 | 7   4   9 | 8  16 3   | 16 2    5    |
 | 8   6   1 | 2  7  5   | 9  34   34   |
 +-----------+-----------+--------------+
 | 5   17  6 | 3  2  9   | 4  17   8    |
 | 2   79  4 | 1  8  67  | 5  3679 36   |
 | 19  3   8 | 67 5  4   | 2  169-7 16  |
 +-----------+-----------+--------------+
 
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 XY-Wing 16-7 pivoted in r9c9 solves it, 7 is strongly linked in r9
 | 
 
 
 I'm confused as to how r3c9 doesn't have a possible 6 in this diagram. My
 basics done diagram was the same as Gianni's first. I needed a second
 19-6 XY wing pivot 9c1 to set the puzzle (-6r3c9) (as in Gianni's 2nd
 diagram).
 
 Hugh
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		| Ajò Dimonios 
 
 
 Joined: 01 May 2017
 Posts: 339
 Location: Sassari Italy
 
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				|  Posted: Wed Aug 23, 2017 10:56 am    Post subject: |   |  
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				| Hi everyone 
 [(1)R7C8-(1)R2C8; (1)R7C8-(1)R4C8=(1)R5C7-(1)R2C6 and (1)R7C8-(1)R7C2=(1)R9C1-(1)R2C2]=>contradiction no candidate 1 in line 2=>-1R7C8=>solution stte.
 
 or -7R7C2 ; R7C2=7 is biunivoca with R7C8=1
 
 or -1R9C1; R9C1=1 is biunivoca with R7C8=1
 
 or -9R9C8; R9C8=9 is biunivoca con R7C8=1
 
 Ciao a Tutti
 Paolo
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		| the_lock_man 
 
 
 Joined: 18 Dec 2012
 Posts: 40
 Location: Portsmarfff, UK
 
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				|  Posted: Wed Aug 23, 2017 11:40 am    Post subject: Re: Aug 23 VH |   |  
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				|  	  | Clement wrote: |  	  |  	  | Code: |  	  | +-----------+-----------+--------------+
 | 146 12  5 | 67 9  167 | 3  8    1246 |
 | 146 8   7 | 5  3  2   | 16 146  9    |
 | 169 129 3 | 4  16 8   | 7  5    12   |
 +-----------+-----------+--------------+
 | 3   5   2 | 9  4  16  | 8  16   7    |
 | 7   4   9 | 8  16 3   | 16 2    5    |
 | 8   6   1 | 2  7  5   | 9  34   34   |
 +-----------+-----------+--------------+
 | 5   17  6 | 3  2  9   | 4  17   8    |
 | 2   79  4 | 1  8  67  | 5  3679 36   |
 | 19  3   8 | 67 5  4   | 2  169-7 16  |
 +-----------+-----------+--------------+
 
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 XY-Wing 16-7 pivoted in r9c9 solves it, 7 is strongly linked in r9
 | 
 
 I got that, then a few basic moves, but then needed a W-Wing on 16, boxes 1 & 9 (the basics had removed the 4 from R2C1) to make R9C1<>1.
 
 Not sure what I missed to make it a 1-stepper.
 
 Now, off to do a squiggly!
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		| Marty R. 
 
 
 Joined: 12 Feb 2006
 Posts: 5770
 Location: Rochester, NY, USA
 
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				|  Posted: Wed Aug 23, 2017 12:34 pm    Post subject: |   |  
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				|  	  | Quote: |  	  | I needed a second 19-6 XY wing pivot 9c1 to set the puzzle (-6r3c9) (as in Gianni's 2nd
 diagram).
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 Me too.
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		| Ajò Dimonios 
 
 
 Joined: 01 May 2017
 Posts: 339
 Location: Sassari Italy
 
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				|  Posted: Wed Aug 23, 2017 1:33 pm    Post subject: |   |  
				| 
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				| Hi everyone 
 
  	  | Code: |  	  | +-----------+------------+--------------+
 | 146 12  5 | 67 9   167 | 3  8    1246 |
 | 146 8   7 | 5  3   2   | 16 146  9    |
 | 169 129 3 | 4  168 168 | 7  5    126  |
 +-----------+------------+--------------+
 | 3   5   2 | 9  4   16  | 8  16   7    |
 | 7   4   9 | 8  16  3   | 16 2    5    |
 | 8   6   1 | 2  7   5   | 9  34   34   |
 +-----------+------------+--------------+
 | 5   17  6 | 3  2   9   | 4  17   8    |
 | 2   79  4 | 1  68  678 | 5  3679 36   |
 | 19  3   8 | 67 5   4   | 2  1679 16   |
 +-----------+------------+--------------+
 
 | 
 Play this puzzle online at the Daily Sudoku site
 
 
 
 
 Another solution with one step after basics.
 
 [(1)R2C7-(1)(R2C8,R3C9,R1C9) and (1)R2C7-(1)R5C7=(1)R4C8-(1)R79C8=(1)R9C9-(1=9)R9C1-(9)R3C1=(9-2)R3C2=(2)R3C9-(2)R1C9=NP(46)(R1C9,R2C8)-(6)R3C9]=>contradiction R3C9=Ø=>-(1)R2C7=>stte.
 
 Ciao a Tutti
 Paolo
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		| Earl 
 
 
 Joined: 30 May 2007
 Posts: 677
 Location: Victoria, KS
 
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				|  Posted: Wed Aug 23, 2017 1:45 pm    Post subject: Aug 23 VH |   |  
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				| I needed two steps: 
 167 xywing @r9c9, -7r9c8
 skyscraper of 1 (r1,7), -1r9c9
 
 Early Earl
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		| dongrave 
 
 
 Joined: 06 Mar 2014
 Posts: 572
 
 
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				|  Posted: Wed Aug 23, 2017 10:02 pm    Post subject: |   |  
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				| I had to use 2 'standard' moves.  My first move (which Clement said solves it!) was the 16-7 XY Wing with pivot at r9c9 and then a 19-6 XY Wing with pivot at r9c1 which solved it!  I have to go back and see if the first XY Wing solves it like Clement said.  (what did i miss?  ugh.) 
 Update: I see that Hugh and I had the same solution.  I think it requires the XY Wing if you only use standard moves.
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		| Ajò Dimonios 
 
 
 Joined: 01 May 2017
 Posts: 339
 Location: Sassari Italy
 
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				|  Posted: Thu Aug 24, 2017 9:26 am    Post subject: |   |  
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				| Hi everyone 
 In the R9C8 cell, only -9R9C8 produces a one-step solution. As I said in a previous post, 9 in R9C8 is biunivoca with 1 in R7C8 (another solution in one step). Virtually when 9 in R9C8 is true even 1 in R7C8 is true and when 1 in R7C8 is true even 9 in R9C8 is true. The consequence of this is that if you prove that 1 in R7C8 is fake (as I wrote in my previous post) even 9 in R9C8 is false.
 
 Ciao a Tutti
 
 Paolo
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		| Clement 
 
 
 Joined: 24 Apr 2006
 Posts: 1113
 Location: Dar es Salaam Tanzania
 
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				|  Posted: Thu Aug 24, 2017 3:42 pm    Post subject: |   |  
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				| You didn't miss anything, I accidentally omitted the 6 in r3c9 which led me to a single stepper solution, it needed one more step as you have done and all others. I apologize for the inconvenience it may have caused. 	  | dongrave wrote: |  	  | I had to use 2 'standard' moves.  My first move (which Clement said solves it!) was the 16-7 XY Wing with pivot at r9c9 and then a 19-6 XY Wing with pivot at r9c1 which solved it!  I have to go back and see if the first XY Wing solves it like Clement said.  (what did i miss?  ugh.) 
 Update: I see that Hugh and I had the same solution.  I think it requires the XY Wing if you only use standard moves.
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		| the_lock_man 
 
 
 Joined: 18 Dec 2012
 Posts: 40
 Location: Portsmarfff, UK
 
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				|  Posted: Fri Aug 25, 2017 11:20 am    Post subject: |   |  
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				|  	  | Clement wrote: |  	  | You didn't miss anything, I accidentally omitted the 6 in r3c9 which led me to a single stepper solution, it needed one more step as you have done and all others. I apologize for the inconvenience it may have caused. 	  | dongrave wrote: |  	  | I had to use 2 'standard' moves.  My first move (which Clement said solves it!) was the 16-7 XY Wing with pivot at r9c9 and then a 19-6 XY Wing with pivot at r9c1 which solved it!  I have to go back and see if the first XY Wing solves it like Clement said.  (what did i miss?  ugh.) 
 Update: I see that Hugh and I had the same solution.  I think it requires the XY Wing if you only use standard moves.
 | 
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 We'll forgive you.
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