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		| Clement 
 
 
 Joined: 24 Apr 2006
 Posts: 1113
 Location: Dar es Salaam Tanzania
 
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				|  Posted: Sat Jan 12, 2013 11:22 pm    Post subject: Jan 13 VH |   |  
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				| Basics Only. |  | 
	
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		| kuskey 
 
 
 Joined: 10 Dec 2008
 Posts: 141
 Location: Pembroke, NH
 
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				|  Posted: Sun Jan 13, 2013 7:16 am    Post subject: Jan 13 VH |   |  
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				| Yup-worked twice for me too. |  | 
	
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		| Pat 
 
 
 Joined: 23 Feb 2010
 Posts: 207
 
 
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				|  Posted: Sun Jan 13, 2013 10:13 am    Post subject: |   |  
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				| 
the only slightly-interesting thing herejust one move,
 a "naked" duo
 is the red herrings —
 the puzzle has 3 duos
 most of which are useless
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		| hughwill 
 
 
 Joined: 05 Apr 2010
 Posts: 424
 Location: Birmingham UK
 
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				|  Posted: Sun Jan 13, 2013 11:00 am    Post subject: Jan 13 VH |   |  
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				| After most basics: 
  	  | Code: |  	  | +----------------+------------+-------------+
 | 123  9    8    | 127  5 237 | 127 6    4  |
 | 1234 3456 1256 | 1267 8 237 | 127 1237 9  |
 | 7    346  126  | 126  4 9   | 5   123  8  |
 +----------------+------------+-------------+
 | 28   1    7    | 4    9 28  | 3   5    6  |
 | 49   46   69   | 3    7 5   | 8   12   12 |
 | 5    28   3    | 28   1 6   | 9   4    7  |
 +----------------+------------+-------------+
 | 128  28   4    | 9    3 78  | 6   127  5  |
 | 6    35   15   | 78   2 4   | 17  9    13 |
 | 239  7    29   | 5    6 1   | 4   8    23 |
 +----------------+------------+-------------+
 
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 Play this puzzle online at the Daily Sudoku site
 
 This still grades as VH at this point but when the sole candidate 8 on
 r8 is put in grading changes to easy. A quirk of the (Samgj's?) original
 algorithm no doubt- but can anyone work out why?
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		| blindleader 
 
 
 Joined: 11 Jan 2013
 Posts: 7
 
 
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				|  Posted: Mon Jan 14, 2013 8:21 pm    Post subject: Re: Jan 13 VH |   |  
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				| I'm new to this site. I find this scenario (hidden single in a grid with a many candidates) very hard unless I slow down and work very methodically. This one stymied me several times yesterday, but today it took about as long as a medium takes. The same thing happens occasionally on sudoko dot org dot uk on puzzles rated below the most difficult and it always gives me fits there, too. 	  | hughwill wrote: |  	  | A quirk of the (Samgj's?) original algorithm no doubt- but can anyone work out why?
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 Maybe the original programmers were in the same boat?
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		| blindleader 
 
 
 Joined: 11 Jan 2013
 Posts: 7
 
 
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				|  Posted: Mon Jan 14, 2013 8:29 pm    Post subject: Re: Jan 13 VH |   |  
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				| I guess in the local dialect, that means locked candidate.  |  | 
	
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		| Marty R. 
 
 
 Joined: 12 Feb 2006
 Posts: 5770
 Location: Rochester, NY, USA
 
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				|  Posted: Mon Jan 14, 2013 9:16 pm    Post subject: Re: Jan 13 VH |   |  
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				|  	  | blindleader wrote: |  	  | I guess in the local dialect, that means locked candidate.  | 
 
 No, not quite. A hidden single is when there is just one occurrence of a number in a row, column or box. It's considered "hidden" because there's at least one other number in the cell. An example is in the grid above in which an 8 is a hidden single in row 8.
 
 Personally, I don't ever see the hidden singles, rather I see the complementary subsets. In that row is a triple 135 which will get to the single after the eliminations.
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		| RobertRattley 
 
 
 Joined: 24 Jun 2007
 Posts: 118
 Location: Australia
 
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				|  Posted: Tue Jan 15, 2013 3:15 pm    Post subject: |   |  
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				| I missed all the above.  Sigh. 
 What I found after hughwill's "most basics", before finishing all the pencil marks, was an x-wing on 8.  So I was quite contented to solve it as a "very hard"!  If it had been published as a hard, I'm confident I'd have finished the pencil marking and found the not-very-hard solution.
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