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		| ZeroAssoluto 
 
 
 Joined: 05 Feb 2017
 Posts: 1019
 Location: Rimini, Italy
 
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				|  Posted: Thu Apr 30, 2020 7:38 am    Post subject: Apr 30 VH |   |  
				| 
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				| Hi everyone, 
 
  	  | Code: |  	  | +-----------+-------------+-----------+
 | 9  37  68 | 167 38  4   | 16  2  5  |
 | 2  1   4  | 679 5   379 | 8   37 69 |
 | 37 5   68 | 169 89  2   | 169 37 4  |
 +-----------+-------------+-----------+
 | 1  2   5  | 4   7   6   | 3   9  8  |
 | 4  8   9  | 3   2   5   | 67  1  67 |
 | 36 36  7  | 8   19  19  | 5   4  2  |
 +-----------+-------------+-----------+
 | 8  679 1  | 2   369 379 | 4   5  79 |
 | 5  79  3  | 79  4   8   | 2   6  1  |
 | 67 4   2  | 5   169 179 | 79  8  3  |
 +-----------+-------------+-----------+
 
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 Play this puzzle online at the Daily Sudoku site
 
 UR 1,9 in r69c56 and -9 in r9c56
 
 
  	  | Code: |  	  | +----------+-----------+---------+
 | 9  37 68 | 17 38  4  | 16 2  5 |
 | 2  1  4  | 6  5   37 | 8  37 9 |
 | 37 5  68 | 19 89  2  | 16 37 4 |
 +----------+-----------+---------+
 | 1  2  5  | 4  7   6  | 3  9  8 |
 | 4  8  9  | 3  2   5  | 7  1  6 |
 | 36 36 7  | 8  19  19 | 5  4  2 |
 +----------+-----------+---------+
 | 8  69 1  | 2  369 39 | 4  5  7 |
 | 5  79 3  | 79 4   8  | 2  6  1 |
 | 67 4  2  | 5  16  17 | 9  8  3 |
 +----------+-----------+---------+
 
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 Play this puzzle online at the Daily Sudoku site
 
 XY-Wing 3,7,9 in r27c6,r8c4 and -7 in r1c4,r9c6
 
 or with only one step
 AIC in r1c2
 if ric2=7 -7 in r3c1,r78c2
 if ric2=3 r7c5=3 r7c2=6 r9c1=7 and -7 in r3c1,r78c2
 
 Ciao Gianni
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		| the_lock_man 
 
 
 Joined: 18 Dec 2012
 Posts: 40
 Location: Portsmarfff, UK
 
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				|  Posted: Thu Apr 30, 2020 11:53 am    Post subject: |   |  
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				| Sorry, Gianni, I don't get your logic there at all. I don't understand where the 9 in r2c6 disappears to in between your two steps. 
 The way I solved it is
 
 
  	  | Code: |  	  | +-----------+-------------+-----------+
 | 9  37  68 | 167 38  4   | 16  2  5  |
 | 2  1   4  | 679 5   379 | 8   37 69 |
 | 37 5   68 | 169 89  2   | 169 37 4  |
 +-----------+-------------+-----------+
 | 1  2   5  | 4   7   6   | 3   9  8  |
 | 4  8   9  | 3   2   5   | 67  1  67 |
 | 36 36  7  | 8   19  19  | 5   4  2  |
 +-----------+-------------+-----------+
 | 8  679 1  | 2   369 37  | 4   5  79 |
 | 5  79  3  | 79  4   8   | 2   6  1  |
 | 67 4   2  | 5   169 179 | 79  8  3  |
 +-----------+-------------+-----------+
 
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 Play this puzzle online at the Daily Sudoku site
 
 X wing on 7s in rows 1 & 8, cols 2 & 4 removes 7 in R7C2 (& R2C4). This then reveals an XY wing 679, pivot R7C2, -9 in R7C9, then STTE.
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		| ZeroAssoluto 
 
 
 Joined: 05 Feb 2017
 Posts: 1019
 Location: Rimini, Italy
 
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				|  Posted: Thu Apr 30, 2020 12:36 pm    Post subject: |   |  
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				| Hi the_lock_man, 
 the reasoning is as follows:
 in R9c56 you cannot have the number 1 and 9 at the same time, but the number 1 in sector 8 can only be in one of the two cells, so even if you do not know in which cell it is located you can be sure that not there will also be the number 9 and at this point it remains only in r9c7.
 I hope I have been clear even though I don't speak english very well.
 
 Ciao Gianni
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		| ZeroAssoluto 
 
 
 Joined: 05 Feb 2017
 Posts: 1019
 Location: Rimini, Italy
 
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				|  Posted: Thu Apr 30, 2020 1:01 pm    Post subject: |   |  
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				| Another reasoning can be followed: in r9c56 there will certainly be either the number 6 or the number 7; one of these combined with r9c1 leaves only the number 9 as a possibility for r9c7. 
 Ciao Gianni
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		| dongrave 
 
 
 Joined: 06 Mar 2014
 Posts: 572
 
 
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				|  Posted: Thu Apr 30, 2020 2:02 pm    Post subject: |   |  
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				|  	  | the_lock_man wrote: |  	  | Sorry, Gianni, I don't get your logic there at all. I don't understand where the 9 in r2c6 disappears to in between your two steps. 
 The way I solved it is
 
 
  	  | Code: |  	  | +-----------+-------------+-----------+
 | 9  37  68 | 167 38  4   | 16  2  5  |
 | 2  1   4  | 679 5   379 | 8   37 69 |
 | 37 5   68 | 169 89  2   | 169 37 4  |
 +-----------+-------------+-----------+
 | 1  2   5  | 4   7   6   | 3   9  8  |
 | 4  8   9  | 3   2   5   | 67  1  67 |
 | 36 36  7  | 8   19  19  | 5   4  2  |
 +-----------+-------------+-----------+
 | 8  679 1  | 2   369 37  | 4   5  79 |
 | 5  79  3  | 79  4   8   | 2   6  1  |
 | 67 4   2  | 5   169 179 | 79  8  3  |
 +-----------+-------------+-----------+
 
 | 
 Play this puzzle online at the Daily Sudoku site
 
 X wing on 7s in rows 1 & 8, cols 2 & 4 removes 7 in R7C2 (& R2C4). This then reveals an XY wing 679, pivot R7C2, -9 in R7C9, then STTE.
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 I also used the 7 X-wing that lock_man used and then the 679 XY-wing that he mentioned (except that the 69-7 XY with pivot at r7c2 gives -7 in r9c7 or alternatively the 67-9 XY with pivot at r9c1 gives -9 in r7c9) but then I also needed a 39-7 XY with pivot at r7c6 giving -7 in r1c4 and r9c6 to solve it!  I don't think the X wing followed by the first XY wing solved it.  Don.
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		| ZeroAssoluto 
 
 
 Joined: 05 Feb 2017
 Posts: 1019
 Location: Rimini, Italy
 
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				|  Posted: Thu Apr 30, 2020 7:17 pm    Post subject: |   |  
				| 
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				|  	  | the_lock_man wrote: |  	  | Sorry, Gianni, I don't get your logic there at all. I don't understand where the 9 in r2c6 disappears to in between your two steps. 
 
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 Sorry, I left a part
 when r9c7 = 9 in column 9 the only 9 is in r2c9 and -9 in r2c6
 
 Ciao Gianni
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