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Free Press October 23, 2009

 
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keith



Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA

PostPosted: Sat Oct 24, 2009 2:09 am    Post subject: Free Press October 23, 2009 Reply with quote

I found an unusual one-step solution:
Code:
Puzzle: FP102309
+-------+-------+-------+
| . . . | 1 . . | . . . |
| . . . | 6 . 9 | 5 . . |
| 3 . 2 | . . . | . . 4 |
+-------+-------+-------+
| . . 1 | . 8 . | 7 . . |
| 6 . . | . . . | . . 2 |
| . . 8 | . 3 . | 9 . . |
+-------+-------+-------+
| 5 . . | . . . | 6 . 1 |
| . . 6 | 3 . . | 2 . . |
| 8 . . | . . 7 | 4 . . |
+-------+-------+-------+

(It's the kind of thing re'born would do.)

Keith
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Marty R.



Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA

PostPosted: Sat Oct 24, 2009 4:21 am    Post subject: Reply with quote

Quote:
(It's the kind of thing re'born would do.)


But not the type of thing Marty would do. My one-stepper would not be described by very many as unusual.

Quote:
W-Wing on 37
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arkietech



Joined: 31 Jul 2008
Posts: 1834
Location: Northwest Arkansas USA

PostPosted: Sat Oct 24, 2009 6:56 am    Post subject: Reply with quote

I like yours better Marty but here is another:
Code:
 *--------------------------------------------------------------------*
 | 79-4   5679-4 579-4  | 1     *24     3      | 8     a269    79     |
 | 1      8     *47     | 6      2-4    9      | 5     b23     37     |
 | 3      69     2      | 578    57     58     | 1      69     4      |
 |----------------------+----------------------+----------------------|
 | 29     3      1      | 59     8      26     | 7      4      56     |
 | 6      4579   4579   | 4579   157    145    | 3      8      2      |
 | 247    457    8      | 457    3      26     | 9      1      56     |
 |----------------------+----------------------+----------------------|
 | 5      2     d37     | 48     9      48     | 6     c37     1      |
 | 479    479    6      | 3      15     15     | 2      79     8      |
 | 8      1      39     | 2      6      7      | 4      5      39     |
 *--------------------------------------------------------------------*
(4=2)r1c5-(2)r1c8=(2-3)r2c8=(3-7)r7c8=(7)r7c3-(7=4)r2c3
 => r1c123,r2c5<>4;
singles
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keith



Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA

PostPosted: Sun Oct 25, 2009 1:49 am    Post subject: Reply with quote

Here is mine:
Code:
 *--------------------------------------------------------------------*
 | 794    56794  5794   | 1      24     3      | 8      269   c79     |
 | 1      8     d47     | 6      24     9      | 5      23     37     |
 | 3      69     2      | 578    57     58     | 1      69     4      |
 |----------------------+----------------------+----------------------|
 | 29     3      1      | 59     8      26     | 7      4      56     |
 | 6      4579   4579   | 4579   157    145    | 3      8      2      |
 | 247    457    8      | 457    3      26     | 9      1      56     |
 |----------------------+----------------------+----------------------|
 | 5      2      3-7    | 48     9      48     | 6     a37     1      |
 | 479    479    6      | 3      15     15     | 2      79     8      |
 | 8      1      39     | 2      6      7      | 4      5     b39     |
 *--------------------------------------------------------------------*

abc is a useless XY-wing with pincers 7. However, grouped coloring in R1 and B1 extends c to d, eliminating 7 in R7C3.

Keith
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Earl



Joined: 30 May 2007
Posts: 677
Location: Victoria, KS

PostPosted: Sun Oct 25, 2009 2:30 am    Post subject: Free Press Reply with quote

xy-chains may be a brute force technique, but they often do the job.
R2C8 - R9C9 are pincers (3) which solve the puzzle.

Earl
of the chain gang
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daj95376



Joined: 23 Aug 2008
Posts: 3854

PostPosted: Sun Oct 25, 2009 3:10 am    Post subject: Reply with quote

This is what I thought Keith was expecting from re'born.

Code:
 There is a useless Skyscraper (*) in <7>
 There is a strong link        (#) in <3>

 (3)r2c8 = (3-7)r7c8 = r7c3 - r3c3 = (7)r2c9 => r2c9<>3
 *--------------------------------------------------------------------*
 | 794    56794  5794   | 1      24     3      | 8      269    79     |
 | 1      8      47*    | 6      24     9      | 5     #23     37*    |
 | 3      69     2      | 578    57     58     | 1      69     4      |
 |----------------------+----------------------+----------------------|
 | 29     3      1      | 59     8      26     | 7      4      56     |
 | 6      4579   4579   | 4579   157    145    | 3      8      2      |
 | 247    457    8      | 457    3      26     | 9      1      56     |
 |----------------------+----------------------+----------------------|
 | 5      2      37*    | 48     9      48     | 6     #37*    1      |
 | 479    479    6      | 3      15     15     | 2      79     8      |
 | 8      1      39     | 2      6      7      | 4      5      39     |
 *--------------------------------------------------------------------*

There's also a strong link in <3> for [c9] => r7c8<>3.
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tlanglet



Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills

PostPosted: Sun Oct 25, 2009 1:59 pm    Post subject: Reply with quote

I just got around to working on this puzzle and spotted an xy-wing 24-7 with vertex 24 in r2c5, pincer 47 in r2c3 and pincer 27 is a pseudocell in col8 to delete 7 in r7c3.

This is very similar to the solution by Keith; it does make the same elimination.

Ted
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