| View previous topic :: View next topic | 
	
	
		| Author | Message | 
	
		| Mogulmeister 
 
 
 Joined: 03 May 2007
 Posts: 1151
 
 
 | 
			
				|  Posted: Fri Dec 03, 2021 9:05 am    Post subject: VH 3rd December |   |  
				| 
 |  
				|  	  | 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 . |
 +-------+-------+-------+
 
 | 
 Play this puzzle online at the Daily Sudoku site
 |  | 
	
		| Back to top |  | 
	
		|  | 
	
		| Mogulmeister 
 
 
 Joined: 03 May 2007
 Posts: 1151
 
 
 | 
			
				|  Posted: Fri Dec 03, 2021 9:08 am    Post subject: |   |  
				| 
 |  
				| 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    |
 +--------------+-----------------+--------------+
 | 
 |  | 
	
		| Back to top |  | 
	
		|  | 
	
		| ZeroAssoluto 
 
 
 Joined: 05 Feb 2017
 Posts: 1019
 Location: Rimini, Italy
 
 | 
			
				|  Posted: Fri Dec 03, 2021 10:16 am    Post subject: |   |  
				| 
 |  
				| 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
 |  | 
	
		| Back to top |  | 
	
		|  | 
	
		| Earl 
 
 
 Joined: 30 May 2007
 Posts: 677
 Location: Victoria, KS
 
 | 
			
				|  Posted: Fri Dec 03, 2021 12:43 pm    Post subject: Dec 03 VH |   |  
				| 
 |  
				| (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
 |  | 
	
		| Back to top |  | 
	
		|  | 
	
		| Mogulmeister 
 
 
 Joined: 03 May 2007
 Posts: 1151
 
 
 | 
			
				|  Posted: Fri Dec 03, 2021 12:49 pm    Post subject: |   |  
				| 
 |  
				| Hi Earl - good spot. |  | 
	
		| Back to top |  | 
	
		|  | 
	
		| Mogulmeister 
 
 
 Joined: 03 May 2007
 Posts: 1151
 
 
 | 
			
				|  Posted: Fri Dec 03, 2021 4:35 pm    Post subject: |   |  
				| 
 |  
				| 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
 |  |
 |  |
 \    /
 \  /
 \/
 r9c4=3 and r9c6 = 5 and r7c5 = 8
 
 | 
 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.
 |  | 
	
		| Back to top |  | 
	
		|  | 
	
		|  |