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Earl
Joined: 30 May 2007
Posts: 677
Location: Victoria, KS
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 Posted: Thu Jun 25, 2009 1:50 am Post subject: June 25 VH |
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The June 25 VH offers many paths: coloring, xy- wings, etc.
Here is a one-stepper.
Solution: 789 xyz wing
Early Earl |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Thu Jun 25, 2009 4:40 am Post subject: |
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| That's the one I used. |
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George Woods
Joined: 28 Mar 2006
Posts: 304
Location: Dorset UK
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| Posted: Thu Jun 25, 2009 9:28 am Post subject: w wing solution |
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| I Couldn't find the XY type solution but founf an "unlikely" W-Wing! |
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cgordon
Joined: 04 May 2007
Posts: 769
Location: ontario, canada
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| Posted: Thu Jun 25, 2009 8:37 pm Post subject: |
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| Just didn't see the aforementioned xy wing. Found xy wings on 679 and 367 plus skyscrapers and ERs. But couldn't do it in less than 4 steps. I guess you have to start off on the right wing. |
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Roger S
Joined: 20 Jun 2009
Posts: 6
Location: UK
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| Posted: Thu Jun 25, 2009 9:03 pm Post subject: |
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Hi
Just joined the forum and am trying to understand Wings
This is as far as I could get, could you help to point out the xyz Wing
+--------------+--------------+-----------------+
| 2 457 1 | 348 567 67 | 6789 45679 3789 |
| 456 3 67 | 48 9 2 | 78 457 1 |
| 8 457 9 | 34 567 1 | 2 4567 37 |
+--------------+--------------+-----------------+
| 3 2789 78 | 6 1 4 | 5 279 789 |
| 79 6 4 | 2 8 5 | 3 1 79 |
| 1 28 5 | 7 3 9 | 68 26 4 |
+--------------+--------------+-----------------+
| 46 478 2 | 9 67 3678 | 1 37 5 |
| 56 579 367 | 1 4 367 | 79 8 2 |
| 79 1 378 | 5 2 378 | 4 379 6 |
+--------------+--------------+-----------------+
Thanks
Roger |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Thu Jun 25, 2009 9:13 pm Post subject: |
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Hi Roger, welcome to the forum. I suggest you Google xyz-wing to get an understanding of this technique better than I could provide.
| Code: |
+--------------+--------------+-----------------+
| 2 457 1 | 348 567 67 | 6789 45679 3789 |
| 456 3 67 | 48 9 2 | 78 457 1 |
| 8 457 9 | 34 567 1 | 2 4567 37 |
+--------------+--------------+-----------------+
| 3 2789 78 | 6 1 4 | 5 279 789 |
| 79 6 4 | 2 8 5 | 3 1 79 |
| 1 28 5 | 7 3 9 | 68 26 4 |
+--------------+--------------+-----------------+
| 46 478 2 | 9 67 3678 | 1 37 5 |
| 56 579 367 | 1 4 367 | 79 8 2 |
| 79 1 378 | 5 2 378 | 4 379 6 |
+--------------+--------------+-----------------+
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Play this puzzle online at the Daily Sudoku site
In this case, the XYZ, XZ and YZ are in cells r4c9, r5c9 and r4c3, eliminating the 7 from r4c8. |
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Roger S
Joined: 20 Jun 2009
Posts: 6
Location: UK
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| Posted: Thu Jun 25, 2009 9:23 pm Post subject: |
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Hi Marty,
Thanks for the prompt reply, I had looked at Brainbashers and understand the concept but could not see it in this particular puzzle
More practice is needed I will work through some more VHs
Roger |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Fri Jun 26, 2009 12:10 am Post subject: |
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| Quote: | | More practice is needed I will work through some more VHs |
Roger, this site publishes a VH only once in four days, on average. If you're looking for more puzzles, try the Puzzles by daj sub-forum here. |
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crunched
Joined: 05 Feb 2008
Posts: 168
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| Posted: Fri Jun 26, 2009 3:10 am Post subject: |
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Not trying to knock daj's sub-forum, but dailysudoku.com has archives going back a long time.
So just go into the archives and pick out vh puzzles.
Then you can also see the discussion on the puzzle for that day here in this discussion forum.
| Marty R. wrote: | | Quote: | | More practice is needed I will work through some more VHs |
Roger, this site publishes a VH only once in four days, on average. If you're looking for more puzzles, try the Puzzles by daj sub-forum here. |
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storm_norm
Joined: 18 Oct 2007
Posts: 1741
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| Posted: Fri Jun 26, 2009 7:21 am Post subject: |
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| Quote: | | Not trying to knock daj's sub-forum, but dailysudoku.com has archives going back a long time. |
I never noticed before that for the first four months of 2005 there wasn't a VH. it wasn't until may 8th, 2005 that the first VH graced the site.
--------
another way to view the elimination that the xyz-wing makes (r4c8 <> 7)...
notice in Marty's grid below how the remote naked pair marked * would be true if the 3 in r9c8 is false. if the 3 in r9c8 is true then the 7 in r4c8 is false.
if the remote naked pair is true, the 7 is false again in r4c8.
| Code: | +--------------+--------------+-----------------+
| 2 457 1 | 348 567 67 | 6789 45679 3789 |
| 456 3 67 | 48 9 2 | 78 457 1 |
| 8 457 9 | 34 567 1 | 2 4567 37 |
+--------------+--------------+-----------------+
| 3 2789 78 | 6 1 4 | 5 2-79 789 |
|*79 6 4 | 2 8 5 | 3 1 *79 |
| 1 28 5 | 7 3 9 | 68 26 4 |
+--------------+--------------+-----------------+
| 46 478 2 | 9 67 3678 | 1 #37 5 |
| 56 579 367 | 1 4 367 | 79 8 2 |
|*79 1 378 | 5 2 378 | 4 *379 6 |
+--------------+--------------+-----------------+ |
(remote naked pair 79) = (3)r9c8 - (3=7)r7c8; r4c8 <> 7
or
written out entirely
{remote naked pair[(7=9)r5c9 - (9=7)r5c1 - (7=9)r9c1 - (9=7)r9c8]} = (3)r9c8 - (3=7)r7c8; r4c8 <> 7 |
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Ema Nymton
Joined: 17 Apr 2009
Posts: 89
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| Posted: Fri Jun 26, 2009 9:03 am Post subject: |
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| Marty R. wrote: | Hi Roger, welcome to the forum. I suggest you Google xyz-wing to get an understanding of this technique better than I could provide.
| Code: |
+--------------+--------------+-----------------+
| 2 457 1 | 348 567 67 | 6789 45679 3789 |
| 456 3 67 | 48 9 2 | 78 457 1 |
| 8 457 9 | 34 567 1 | 2 4567 37 |
+--------------+--------------+-----------------+
| 3 2789 78 | 6 1 4 | 5 279 789 |
| 79 6 4 | 2 8 5 | 3 1 79 |
| 1 28 5 | 7 3 9 | 68 26 4 |
+--------------+--------------+-----------------+
| 46 478 2 | 9 67 3678 | 1 37 5 |
| 56 579 367 | 1 4 367 | 79 8 2 |
| 79 1 378 | 5 2 378 | 4 379 6 |
+--------------+--------------+-----------------+
|
Play this puzzle online at the Daily Sudoku site
In this case, the XYZ, XZ and YZ are in cells r4c9, r5c9 and r4c3, eliminating the 7 from r4c8. |
I can see using the above grid that the XYZ eliminates the 7 in row 4 column 8. Does the XYZ in row 9 column 8 (r7c8 =37)/(r9c1 = 79)(r9c8 = 379) eliminate the 7 from row 8 column 7? Does the same XYZ eliminate the other 7's in row 9?
~@:o?
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sdq_pete
Joined: 30 Apr 2007
Posts: 119
Location: Rotterdam, NL
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| Posted: Fri Jun 26, 2009 12:42 pm Post subject: |
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No. This XYZ is unproductive. Any eliminations from an XYZ are always in the same block as the tri-value AND the same row containing the tri-value and the external bi-value. If you follow me. i.e. any cells in which potential eliminations occur must "see" all 3 cells of the XYZ
Peter |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Fri Jun 26, 2009 3:41 pm Post subject: |
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| Quote: | | I never noticed before that for the first four months of 2005 there wasn't a VH. it wasn't until may 8th, 2005 that the first VH graced the site. |
Just for the record, at the time I joined in February 2006, any VH could be solved with X-Wings. It wasn't until sometime later, probably still in 2006, that XY- and XYZ-Wings were added. |
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