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		Marty R.
 
 
  Joined: 12 Feb 2006 Posts: 5770 Location: Rochester, NY, USA
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				 Posted: Wed Feb 22, 2012 4:22 pm    Post subject: Vanhegan extreme | 
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				Puzzle 6-633429, rated 1.3.0.1.1
 
 
Played one Finned X-Wing but hit the brick wall.
 
 
 	  | Code: | 	 		  
 
+----------------+---------------+---------------+
 
| 3    57   159  | 589  589  6   | 179  4     2  |
 
| 4    6    1259 | 2359 7    135 | 139  1359  8  |
 
| 125  257  8    | 4    259  135 | 6    13579 35 |
 
+----------------+---------------+---------------+
 
| 7    248  24   | 38   1    348 | 5    6     9  |
 
| 59   1    6    | 7    59   2   | 34   8     34 |
 
| 589  458  3    | 589  6    458 | 27   27    1  |
 
+----------------+---------------+---------------+
 
| 125  3    7    | 6    245  9   | 8    125   45 |
 
| 1258 2458 1245 | 25   3    7   | 1249 1259  6  |
 
| 6    9    245  | 1    2458 58  | 234  235   7  |
 
+----------------+---------------+---------------+
 
 | 	  
 
Play this puzzle online at the Daily Sudoku site | 
			 
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		JC Van Hay
 
 
  Joined: 13 Jun 2010 Posts: 494 Location: Charleroi, Belgium
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				 Posted: Wed Feb 22, 2012 6:28 pm    Post subject:  | 
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				From a B/B-Plot POV, the first weakest points in the brick wall to look at are the cells r2c4, r1c7 and r3c8.
 
 
"Fortunately", they enter into an AIC (involving only bilocals) as follows :
 
 
 	  | Code: | 	 		  +--------------------+----------------------+--------------------+
 
| 3     57    5(19)  | 589      589     6   | 9(17)  4        2  |
 
| 4     6     15(29) | 35-9(2)  7       135 | 139    1359     8  |
 
| 125   257   8      | 4        5-2(9)  135 | 6      135(79)  35 |
 
+--------------------+----------------------+--------------------+
 
| 7     248   24     | 38       1       348 | 5      6        9  |
 
| 59    1     6      | 7        59      2   | 34     8        34 |
 
| 589   458   3      | 589      6       458 | 27     27       1  |
 
+--------------------+----------------------+--------------------+
 
| 125   3     7      | 6        245     9   | 8      125      45 |
 
| 1258  2458  1245   | 25       3       7   | 1249   1259     6  |
 
| 6     9     245    | 1        2458    58  | 234    235      7  |
 
+--------------------+----------------------+--------------------+
 
 
5-SIS AIC : 2r2c4=(2-9)r2c3=(9-1)r1c3=(1-7)r1c7=(7-9)r3c8=9r3c5 => -9r2c4, -2r3c5; stte | 	 
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		arkietech
 
 
  Joined: 31 Jul 2008 Posts: 1834 Location: Northwest Arkansas USA
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				 Posted: Wed Feb 22, 2012 8:17 pm    Post subject:  | 
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				 	  | JC Van Hay wrote: | 	 		  
 
 
 	  | Code: | 	 		  +--------------------+----------------------+--------------------+
 
| 3     57    5(19)  | 589      589     6   | 9(17)  4        2  |
 
| 4     6     15(29) | 35-9(2)  7       135 | 139    1359     8  |
 
| 125   257   8      | 4        5-2(9)  135 | 6      135(79)  35 |
 
+--------------------+----------------------+--------------------+
 
| 7     248   24     | 38       1       348 | 5      6        9  |
 
| 59    1     6      | 7        59      2   | 34     8        34 |
 
| 589   458   3      | 589      6       458 | 27     27       1  |
 
+--------------------+----------------------+--------------------+
 
| 125   3     7      | 6        245     9   | 8      125      45 |
 
| 1258  2458  1245   | 25       3       7   | 1249   1259     6  |
 
| 6     9     245    | 1        2458    58  | 234    235      7  |
 
+--------------------+----------------------+--------------------+
 
 
5-SIS AIC : 2r2c4=(2-9)r2c3=(9-1)r1c3=(1-7)r1c7=(7-9)r3c8=9r3c5 => -9r2c4, -2r3c5; stte | 	 
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My favorite pattern is there also: there is a strong link in 2 from r2c4 to both r2c3 and r3c5 which are connected as you show. The result is r2c4 has to be a 2.
 
 
2r2c4=(2-9)r2c3=(9-1)r1c3=(1-7)r1c7=(7-9)r3c8=(9-2)r3c5=2r2c4 => r2c4=2 | 
			 
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		Marty R.
 
 
  Joined: 12 Feb 2006 Posts: 5770 Location: Rochester, NY, USA
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				 Posted: Wed Feb 22, 2012 10:34 pm    Post subject:  | 
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				Thanks JC and Dan for the responses, which I unfortunately don't understand.
 
 
I don't know what "B/B-plot" and "bilocals" mean and can't follow the AIC chain.
 
 
Dan, can you spot that pattern and know what cell must=2 or do you have to do some testing after you spot it? Does the pattern have a name?
 
 
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		arkietech
 
 
  Joined: 31 Jul 2008 Posts: 1834 Location: Northwest Arkansas USA
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				 Posted: Wed Feb 22, 2012 11:20 pm    Post subject:  | 
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				 	  | Marty R. wrote: | 	 		  | Dan, can you spot that pattern and know what cell must=2 or do you have to do some testing after you spot it? Does the pattern have a name? | 	  
 
 
I look for a cell with a candidate with two strong links. Then I try to connect the linked cells with a chain. If I can the cell with two strong links can be set to the candidate.
 
 
if the start of the chain = 2 and the end of the chain = 2 and both are the same cell then it must = 2.  
 
 
I have to admit I missed this one. I spotted it in JC's solution.
 
 
It is called a Discontinuous loop or a turbot fish if the chain contains 5 cells.
 
 
hope this helps
 
 
dan | 
			 
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		daj95376
 
 
  Joined: 23 Aug 2008 Posts: 3854
 
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				 Posted: Wed Feb 22, 2012 11:43 pm    Post subject:  | 
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				 	  | Code: | 	 		  (2)r2c4=(2-9)r2c3=(9-1)r1c3=(1-7)r1c7=(7-9)r3c8=(9-2)r3c5=(2)r2c4 => r2c4=2
 
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Dan's chain as a sequence of overlapping strong links:
 
 
 	  | Code: | 	 		  r2c4<>2 -> r2c3=3
 
           r2c3<>9 -> r1c3=9
 
                      r1c3<>1 -> r1c7=1
 
                                 r1c7<>7 -> r3c8=7
 
                                            r3c8<>9 -> r3c5=9
 
                                                       r3c5<>2 -> r2c4=2
 
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		JC Van Hay
 
 
  Joined: 13 Jun 2010 Posts: 494 Location: Charleroi, Belgium
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				 Posted: Fri Feb 24, 2012 7:57 am    Post subject:  | 
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				 	  | Marty R. wrote: | 	 		  | I don't know what "B/B-plot" and "bilocals" mean and can't follow the AIC chain. | 	  
 
Marty, Sudopedia is now accessible again. Look for the definitions and eventually for more informations from here.
 
 
Best regards, JC. | 
			 
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