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Earl
Joined: 30 May 2007 Posts: 677 Location: Victoria, KS
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Posted: Sat Mar 22, 2008 1:00 pm Post subject: March 22 DB |
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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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Play this puzzle online at the Daily Sudoku site |
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Marty R.
Joined: 12 Feb 2006 Posts: 5770 Location: Rochester, NY, USA
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Posted: Sat Mar 22, 2008 5:06 pm Post subject: |
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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
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Posted: Sat Mar 22, 2008 6:53 pm Post subject: |
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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
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Posted: Sun Mar 23, 2008 9:59 am Post subject: |
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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
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Posted: Sun Mar 23, 2008 10:55 am Post subject: |
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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
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Posted: Mon Mar 24, 2008 9:37 pm Post subject: |
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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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