| View previous topic :: View next topic | 
	
	
		| Author | Message | 
	
		| Clement 
 
 
 Joined: 24 Apr 2006
 Posts: 1113
 Location: Dar es Salaam Tanzania
 
 | 
			
				|  Posted: Sat Jun 23, 2012 10:16 pm    Post subject: Jun 24 VH |   |  
				| 
 |  
				| XY-Wing 57 78 58 pivoted in r3c8 solves it by setting r7c2<>5. |  | 
	
		| Back to top |  | 
	
		|  | 
	
		| dongrave 
 
 
 Joined: 06 Mar 2014
 Posts: 572
 
 
 | 
			
				|  Posted: Thu Mar 06, 2014 2:43 pm    Post subject: Jun 24 2012 VH |   |  
				| 
 |  
				| I'm going back through the archive now to try to solve the VH ones.  How did you eliminate the candidate 5 from r3c8?  I had the candidates 578 instead of just 78 in r3c8 so I missed the XY wing.  Thanks. |  | 
	
		| Back to top |  | 
	
		|  | 
	
		| Marty R. 
 
 
 Joined: 12 Feb 2006
 Posts: 5770
 Location: Rochester, NY, USA
 
 | 
			
				|  Posted: Thu Mar 06, 2014 5:49 pm    Post subject: |   |  
				| 
 |  
				|  	  | Code: |  	  | +--------------+--------+-------------+
 | 16   8  56   | 7 15 9 | 4   3   2   |
 | 17   3  2    | 4 6  8 | 159 579 579 |
 | 4    57 9    | 3 15 2 | 158 578 6   |
 +--------------+--------+-------------+
 | 578  9  4    | 1 2  3 | 58  6   578 |
 | 57   2  1    | 8 79 6 | 3   579 4   |
 | 3678 67 3678 | 5 79 4 | 2   1   789 |
 +--------------+--------+-------------+
 | 9    56 568  | 2 4  1 | 7   58  3   |
 | 37   4  37   | 9 8  5 | 6   2   1   |
 | 2    1  58   | 6 3  7 | 589 4   589 |
 +--------------+--------+-------------+
 
 | 
 Play this puzzle online at the Daily Sudoku site
 
 I don't know if I'm done with basics yet. But look at row 2. The 5s are restricted to row 2 in box 3, thus no other rows in that box can contain 5.
 |  | 
	
		| Back to top |  | 
	
		|  | 
	
		| dongrave 
 
 
 Joined: 06 Mar 2014
 Posts: 572
 
 
 | 
			
				|  Posted: Thu Mar 06, 2014 6:21 pm    Post subject: |   |  
				| 
 |  
				| Oh!  How obvious!  How did I miss that?  I actually still had a 5 in r1c1 and r2c1 even though I knew that r4c1 or r5c1 had to be a 5.  Thanks! |  | 
	
		| Back to top |  | 
	
		|  | 
	
		| Marty R. 
 
 
 Joined: 12 Feb 2006
 Posts: 5770
 Location: Rochester, NY, USA
 
 | 
			
				|  Posted: Thu Mar 06, 2014 9:00 pm    Post subject: |   |  
				| 
 |  
				| That situation in row 2 is called either Locked Candidates or Box-Line Interactions and are extremely easy to miss. Many people miss them, including myself. |  | 
	
		| Back to top |  | 
	
		|  | 
	
		|  |