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A peaceful puzzle

 
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Victor



Joined: 29 Sep 2005
Posts: 207
Location: NI

PostPosted: Tue Apr 08, 2008 10:10 pm    Post subject: A peaceful puzzle Reply with quote

M5368492 (15)
Code:

+-------+-------+-------+
| . 4 . | . 3 . | . 2 . |
| 5 . 1 | . . 6 | 3 . 4 |
| 2 . . | 5 . . | . . 7 |
+-------+-------+-------+
| . . 9 | . . . | . . 2 |
| . . . | 8 . 7 | . . . |
| 6 . . | . . . | 8 . . |
+-------+-------+-------+
| 1 . . | 3 . . | . . 9 |
| 9 . 7 | . . 4 | 6 . 8 |
| . 2 . | . 7 . | . 1 . |
+-------+-------+-------+

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Earl



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

PostPosted: Wed Apr 09, 2008 1:15 am    Post subject: peaceful Reply with quote

A w-wing (35) puts it to rest.

Earl
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nataraj



Joined: 03 Aug 2007
Posts: 1048
Location: near Vienna, Austria

PostPosted: Wed Apr 09, 2008 5:56 am    Post subject: Reply with quote

Very quickly reached this stage:
Code:

+--------------------------+--------------------------+--------------------------+
| 7       4       68       | 9       3       18       | 15      2       156      |
| 5       89      1        | 7       2       6        | 3       89      4        |
| 2       389     368      | 5       4       18       | 19      689     7        |
+--------------------------+--------------------------+--------------------------+
| 48#     158     9        | 14      56      3        | 7       456     2        |
| 34#     135     2        | 8       569     7        | 159     34569   1356     |
| 6       7       35#      | 14      59      2        | 8       3459    13-5     |
+--------------------------+--------------------------+--------------------------+
| 1       6       4        | 3       8       5        | 2       7       9        |
| 9       35      7        | 2       1       4        | 6       35      8        |
| 38#     2       3-58     | 6       7       9        | 4       1       35#      |
+--------------------------+--------------------------+--------------------------+


Maybe I would have looked a long time for xy-wings, but somehow I must have rememered Earl's hint about the 35s, so that's what I found (the long chain marked # between r9c9 and r6c3).
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Johan



Joined: 25 Jun 2007
Posts: 206
Location: Bornem Belgium

PostPosted: Wed Apr 09, 2008 6:59 am    Post subject: Reply with quote

There is a flightless *{358} xyz-wing which places digit <5> in R8C2, collapsing the puzzle, either one of these three cells must contain a <3>

R9C13=3 => R8C2=5
R6C3=3 => R3C2=3 => R8C2=5
Code:
+-------------------------+-------------------------+-------------------------+
| 7         4        68   | 9         3         18  | 15       2        156   |
| 5         89       1    | 7         2         6   | 3        89       4     |
| 2         389      368  | 5         4         18  | 19       689      7     |
+-------------------------+-------------------------+-------------------------+
| 48        158      9    | 14        56        3   | 7        456      2     |
| 34        135      2    | 8         569       7   | 159      34569    1356  |
| 6         7      * 35   | 14        59        2   | 8        3459     135   |
+-------------------------+-------------------------+-------------------------+
| 1         6        4    | 3         8         5   | 2        7        9     |
| 9       -[3]5      7    | 2         1         4   | 6        35       8     |
|*38        2      * 358  | 6         7         9   | 4        1        35    |
+-------------------------+-------------------------+-------------------------+
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Earl



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

PostPosted: Wed Apr 09, 2008 4:36 pm    Post subject: peaceful Reply with quote

I am not familiar with a "flightless" xyz-wing.
Also, I do not see the necessary link of boxes 3 & 7 to make R8C2 a 5. I would appreciate more details. Guess I am having a "senior" day.

Earl
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Marty R.



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

PostPosted: Wed Apr 09, 2008 5:06 pm    Post subject: Reply with quote

I interpret "flightless" wings to be wings that make no direct eliminations.
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Asellus



Joined: 05 Jun 2007
Posts: 865
Location: Sonoma County, CA, USA

PostPosted: Wed Apr 09, 2008 6:15 pm    Post subject: Reply with quote

Box 9 doesn't need to be involved in explaining that flightless XYZ Wing elimination. The grouped <3>s in r79c3 can be transported to r3c2 due to the strong link in r3. Then, r9c1 and r3c2 serve as pincers to eliminate the <3> in r8c2.

Think of it this way: At least one of the three XYZ Wing cells must be <3>. If r9c1 is <3>, r8c2 cannot be <3>. If r9c1 is not <3>, then one of r79c3 is <3>, so r3c3 is not <3>, so r3c2 is <3> and, again, r8c2 is not <3>. Either way, there is no <3> in r8c2.
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