How do you call this tecnique?

Advanced methods and approaches for solving Sudoku puzzles

How do you call this tecnique?

Postby claudiarabia » Sun Oct 12, 2008 12:57 pm

Code: Select all
 6 . 7 . 8 . 5 . 3
. 9 . . . . . 8 .
4 . . . . . . . 6
. . . 4 . . . . .
5 . . 2 . 1 . . .
9 . . . . 3 . . 8
3 . . . . . . . 7
. . . . . . . 6 .
7 . 5 . 1 . 8 . 9

 *-----------*
 |6.7|.8.|5.3|
 |.93|...|.8.|
 |458|.3.|..6|
 |---+---+---|
 |.3.|4.8|6.5|
 |586|2.1|.34|
 |974|..3|..8|
 |---+---+---|
 |3..|8..|.57|
 |8..|...|36.|
 |7.5|31.|8.9|
 *-----------*

 
 *-----------------------------------------------------------*
 | 6    *12    7     | 19    8     249   | 5     49    3     |
 |*12    9     3     | 567   456   456   | 47    8    *12    |
 | 4     5     8     | 179   3     279   | 1279  1279  6     |
 |-------------------+-------------------+-------------------|
 | 12    3     12    | 4     79    8     | 6     79    5     |
 | 5     8     6     | 2     79    1     | 79    3     4     |
 | 9     7     4     | 56    56    3     | 12    12    8     |
 |-------------------+-------------------+-------------------|
 | 3     1246  129   | 8     2469  2469  | 124   5     7     |
 | 8   #4-12   129   | 579   245   4579  | 3     6    *12    |
 | 7     246   5     | 3     1     46    | 8     24    9     |
 *-----------------------------------------------------------*


r1c2, r2c19, r8c29 with the values 12 form a kind of loop with an odd number of cells. If you would eliminate 4 from r8c2 and leave 12 in r8c2 there would be an impossible turbot-fish-constellation. r8c2 would stay empty if you apply the string-kite on 1 and 2 in r8c2. Furthermore there can't be five pairs of the same two values in a ring.

How is this strategy called here? I can remember carcul had described once something like this but I don't find it now.

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Postby daj95376 » Sun Oct 12, 2008 1:43 pm

Your asterisk (*) cells form a 4-cell Remote Pair. For either candidate value, coloring these cells will produce [r8c2]<>1 and [r8c2]<>2, respectively.

For more information, check out ...

http://www.dailysudoku.com/sudoku/forums/viewtopic.php?p=8277&sid=1d601fda1f8caa3447bd4590ea547dfc#8277
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