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March 22 DB

 
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Earl



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

PostPosted: Sat Mar 22, 2008 1:00 pm    Post subject: March 22 DB Reply with quote

The March 22 DB offers an x-wing (2) then a naked pair (39), then an x-y wing (168) as a solution.


Earl


Code:

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

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Marty R.



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

PostPosted: Sat Mar 22, 2008 5:06 pm    Post subject: Reply with quote

I had three ERs, a W-Wing, deadly pattern, an X-Wing and an XY-Wing with pincer coloring, but never spotted any puzzle-busting XY-Wings, so I turned to my Medusa crutch to finish it off.
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storm_norm



Joined: 18 Oct 2007
Posts: 1741

PostPosted: Sat Mar 22, 2008 6:53 pm    Post subject: Reply with quote

x-wing on 2
then looking for xy-wings I found an xy-chain starting in r3c4 36-69-39-39-39 removes 3 from r3c9
then xy-wing {1,6,8} which proved to be very powerful.
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nataraj



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

PostPosted: Sun Mar 23, 2008 9:59 am    Post subject: Reply with quote

After x-wing (2) and short cleanup, this is the position with the powerful xy-wing (pivot r4c1):
Code:

+--------------------------+--------------------------+--------------------------+
| 7       136     136      | 236     69      29       | 4       5       8        |
| 5       2       36       | 7       4       8        | 1       9       36       |
| 4       9       8        | 36      5       1        | 367     2       367      |
+--------------------------+--------------------------+--------------------------+
| 18      7       5        | 26      18      3        | 69      4       269      |
| 3689    368     2369     | 5       68      4        | 67      1       267      |
| 126     16      4        | 9       126     7        | 8       3       5        |
+--------------------------+--------------------------+--------------------------+
| 139     135     139      | 8       7       59       | 2       6       4        |
| 29      4       7        | 1       239     6        | 5       8       39       |
| 68      568     26       | 4       39      25       | 39      7       1        |
+--------------------------+--------------------------+--------------------------+
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Victor



Joined: 29 Sep 2005
Posts: 207
Location: NI

PostPosted: Sun Mar 23, 2008 10:55 am    Post subject: Reply with quote

Luckily (?) didn't see Nataraj's XY-wing (which I've just noticed that Earl pointed out himself). Instead, there's a flightless one pivoted on r5c1, with r9c5 extended by colouring to r8c9. That kills the 3 in r3c9, leaving a UR of the kind that caused much comment recently, two or three VHs ago.
Thanks Earl - enjoyed this one.
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dejsmith



Joined: 23 Oct 2005
Posts: 42

PostPosted: Mon Mar 24, 2008 9:37 pm    Post subject: Reply with quote

I am trying to attempt more varied techniques such as Victor's flightless XY Wing with coloring as I work puzzles (rather than just jump straight to X/XY/XYZ Wings). I believe it is making me better; & certainly more observant/open to alternatives. Thanks also, Victor, for explaining my error on that W Wing with coloring a few VHs back. Similar logic, I think.

Dave
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