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		Mogulmeister
 
 
  Joined: 03 May 2007 Posts: 1151
 
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				 Posted: Fri Dec 03, 2021 9:05 am    Post subject: VH 3rd December | 
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				 	  | Code: | 	 		  
 
+-------+-------+-------+
 
| . 3 5 | . 9 . | . 2 . |
 
| . . . | . . 1 | 3 5 . |
 
| 2 . . | . . 6 | 4 . 7 |
 
+-------+-------+-------+
 
| . . . | . . . | . 3 9 |
 
| . . 6 | . 4 . | 2 . . |
 
| 3 5 . | . . . | . . . |
 
+-------+-------+-------+
 
| 7 . 3 | 1 . . | . . 2 |
 
| . 6 1 | 2 . . | . . . |
 
| . 9 . | . 6 . | 7 8 . |
 
+-------+-------+-------+
 
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Play this puzzle online at the Daily Sudoku site | 
			 
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		Mogulmeister
 
 
  Joined: 03 May 2007 Posts: 1151
 
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				 Posted: Fri Dec 03, 2021 9:08 am    Post subject:  | 
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				After basics
 
 	  | Code: | 	 		  +--------------+-----------------+--------------+
 
| 46  3   5    | 478  9    478   | 1   2   68   |
 
| 469 47  479  | 48   2    1     | 3   5   68   |
 
| 2   1   8    | 5    3    6     | 4   9   7    |
 
+--------------+-----------------+--------------+
 
| 148 2   47   | 678  1578 578   | 68  3   9    |
 
| 189 78  6    | 3789 4    378   | 2   17  5    |
 
| 3   5   79   | 6789 178  2     | 68  17  4    |
 
+--------------+-----------------+--------------+
 
| 7   48  3    | 1    58   4589  | 59  6   2    |
 
| 58  6   1    | 2    578  5789  | 59  4   3    |
 
| 45  9   2    | 34   6    345   | 7   8   1    |
 
+--------------+-----------------+--------------+ | 	 
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		ZeroAssoluto
 
 
  Joined: 05 Feb 2017 Posts: 1020 Location: Rimini, Italy
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				 Posted: Fri Dec 03, 2021 10:16 am    Post subject:  | 
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				Hi everyone, 
 
 
first step W-Wing 5,8 in r7c5,r8c1 SL with number 5 in r9c16 and -8 in r7c2,r8c56 
 
 
and XY-Wing 1,7,9 in r5c18,r6c3 and -7 in r6c8 
 
 
Ciao Gianni | 
			 
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		Earl
 
 
  Joined: 30 May 2007 Posts: 677 Location: Victoria, KS
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				 Posted: Fri Dec 03, 2021 12:43 pm    Post subject: Dec 03 VH | 
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				(Correction)
 
My first step before the 179 xywing was: 
 
458xywing@R7C2, -5R9C6
 
 
Early Earl
  Last edited by Earl on Fri Dec 03, 2021 4:10 pm; edited 2 times in total | 
			 
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		Mogulmeister
 
 
  Joined: 03 May 2007 Posts: 1151
 
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				 Posted: Fri Dec 03, 2021 12:49 pm    Post subject:  | 
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				| Hi Earl - good spot. | 
			 
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		Mogulmeister
 
 
  Joined: 03 May 2007 Posts: 1151
 
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				 Posted: Fri Dec 03, 2021 4:35 pm    Post subject:  | 
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				Another way to look at this is to see that we have an almost XY wing - the killer <179> as used above.
 
 
 
However, at the start that is spoiled by the extra 8 in r5c1. 
 
 
 	  | Code: | 	 		  Either the 8 at r5c1 is true or the <179> XY Wing is true.
 
 
Let's look at making that 8.
 
 
r5c1 = 8 then r8c1 = 5 r9c1 = 4 and r7c2 = 8
 
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                           r9c4=3 and r9c6 = 5 and r7c5 = 8 
 
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Two 8's in row 7 - contradiction so we know that r5c1 can NOT be 8
 
 
The XY Wing <179> is true and puzzle solved. | 
			 
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