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		Ajò Dimonios
 
 
  Joined: 01 May 2017 Posts: 339 Location: Sassari Italy
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				 Posted: Thu Jul 27, 2017 11:30 am    Post subject: sett.sudoku21072017 | 
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				Hi everyone
 
 
 	  | Code: | 	 		  
 
+-------+-------+-------+
 
| 1 2 . | . . 6 | . . . |
 
| 8 . 6 | 4 . 2 | . . . |
 
| . 4 . | . 1 . | . . . |
 
+-------+-------+-------+
 
| . 8 . | 2 . . | . 7 5 |
 
| . . 2 | . . . | 9 . . |
 
| 6 7 . | . . 8 | . 4 . |
 
+-------+-------+-------+
 
| . . . | . 5 . | . 8 . |
 
| . . . | 8 . 7 | 3 . 2 |
 
| . . . | 9 . . | . 6 4 |
 
+-------+-------+-------+
 
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Play this puzzle online at the Daily Sudoku site
 
 
Ciao a Tutti
 
Paolo | 
			 
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		JC Van Hay
 
 
  Joined: 13 Jun 2010 Posts: 494 Location: Charleroi, Belgium
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				 Posted: Thu Jul 27, 2017 3:36 pm    Post subject:  | 
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				11 singles; r5c45=67
 
1C4 -> 1 unique solution :
 
 	  | Code: | 	 		  +-----------------------+---------------------+------------------+
 
| 1      2       3579   | 357     8    6      | 4    359    379  |
 
| 8      359     6      | 4       379  2      | 157  1359   1379 |
 
| 3579   4       3579   | 357     1    359    | 8    2      6    |
 
+-----------------------+---------------------+------------------+
 
| (349)  8       1349   | 2       349  1349   | 6    7      5    |
 
| (345)  (135)   2      | 67      67   134(5) | 9    3(1)   8    |
 
| 6      7       1359   | 3-1(5)  39   8      | 2    4      3(1) |
 
+-----------------------+---------------------+------------------+
 
| 2      1369    13479  | 136     5    134    | 17   8      179  |
 
| (459)  569(1)  459(1) | 8       46   7      | 3    59(1)  2    |
 
| 357    (135)   8      | 9       2    13     | 157  6      4    |
 
+-----------------------+---------------------+------------------+
 
1r6c9 1r5c8
 
5r6c4       5r5c6
 
      1r5c2 5r5c2 3r5c2
 
            5r5c1 3r5c1 4r5c1
 
                  3r4c1 4r4c1 9r4c1
 
                        4r8c1 9r8c1 5r8c1
 
                  3r9c2             5r9c2 1r9c2
 
      1r8c8                               1r8c23 -> [1r6c9==5r6c4]-1r6c4; stte | 	 
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		Ajò Dimonios
 
 
  Joined: 01 May 2017 Posts: 339 Location: Sassari Italy
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				 Posted: Sat Jul 29, 2017 4:44 pm    Post subject:  | 
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				Hi everyone
 
 
 	  | Code: | 	 		  
 
+-----------------+--------------+---------------+
 
| 1    2    3579  | 357 8   6    | 4   359  379  |
 
| 8    359  6     | 4   379 2    | 157 1359 1379 |
 
| 3579 4    3579  | 357 1   359  | 8   2    6    |
 
+-----------------+--------------+---------------+
 
| 349  8    1349  | 2   349 1349 | 6   7    5    |
 
| 345  135  2     | 67  67  1345 | 9   13   8    |
 
| 6    7    1359  | 135 39  8    | 2   4    13   |
 
+-----------------+--------------+---------------+
 
| 2    1369 13479 | 136 5   134  | 17  8    179  |
 
| 459  1569 1459  | 8   46  7    | 3   159  2    |
 
| 357  135  8     | 9   2   13   | 157 6    4    |
 
+-----------------+--------------+---------------+
 
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Play this puzzle online at the Daily Sudoku site
 
 
Solution with one step after basics.
 
 
[(1-5)R6C4=(5-4)R5C6=(4)R5C1-(4)R8C1;
 
[(1)R6C4-(1)R4C6=(1)R4C3-(1)R78C3 and (1)R6C4-(1)R6C9=(1)R5C8-(1)R8C8=(1)R8C2-(1)R9C2]
 
[(1-5)R6C4=(5)R6C3-(5)R5C2; (1)R6C4-(1)R4C6=(1)R4C3-(1=3)R5C2-(3)R9C2]
 
[(1-5)R6C4=(5-4)R5C6=(4)R5C1-(4)R4C1; (1-5)R6C4=(5)R6C3-(5)R5C2; (1)R6C4-(1)R4C6=(1)R4C3-(1=3)R5C2-(3=9)R4C1-(9)R8C1]]=>contradiction two singles 5 in box 7 (R8C1,R9C2)=>-1R6C4=>solution stte.
 
 
Ciao a Tutti 
 
Paolo | 
			 
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		JC Van Hay
 
 
  Joined: 13 Jun 2010 Posts: 494 Location: Charleroi, Belgium
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				 Posted: Sat Jul 29, 2017 5:45 pm    Post subject:  | 
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				Hi Paolo,
 
 
The constraints 1R4 and 5R6 are not necessary.
 
By comparison with my solution, here is your simplified step written in a more condensed and readable way :
 
 	  | Code: | 	 		  1r6c9 1r5c8 
 
5r6c4       5r5c6 
 
      1r5c2 5r5c2 3r5c2 
 
            4r5c6       4r5c1 
 
                  3r4c1 4r4c1 9r4c1 
 
                        4r8c1 9r8c1 5r8c1 
 
                  3r9c2             5r9c2 1r9c2 
 
      1r8c8                               1r8c23 -> [1r6c9==5r6c4]-1r6c4; stte
 
 | 	  As you can see, you used the simpler constraint 4R5 instead of R5C1!
 
 
JC | 
			 
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		Ajò Dimonios
 
 
  Joined: 01 May 2017 Posts: 339 Location: Sassari Italy
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				 Posted: Sun Jul 30, 2017 1:56 pm    Post subject:  | 
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				Hi JC
 
 
Thanks for the synthesis and explanation of the solution.
 
 
Ciao a Tutti
 
Paolo | 
			 
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