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Nov 11 VH

 
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keith



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

PostPosted: Sun Nov 11, 2007 3:44 am    Post subject: Nov 11 VH Reply with quote

Interesting, in that I could identify the wings long before they were useful.

Marty, if you want to get the puzzle ahead of the time zone, sign up for e-mail!

Keith

Puzzle, with candidates:

Code:
+----------------------+----------------------+----------------------+
| 5      2      78     | 478    479    1      | 3      478    6      |
| 9      137    4      | 578    6      358    | 12578  1578   278    |
| 67     1367   13678  | 2      34579  3589   | 145789 14578  78     |
+----------------------+----------------------+----------------------+
| 2467   8      267    | 1456   12345  2356   | 147    13467  9      |
| 1      46     26     | 9      234    7      | 48     3468   5      |
| 3      45679  679    | 14568  145    568    | 1478   2      78     |
+----------------------+----------------------+----------------------+
| 267    13679  123679 | 1567   12579  4      | 2578   3578   2378   |
| 247    3479   2379   | 57     8      259    | 6      357    1      |
| 8      167    5      | 3      127    26     | 27     9      4      |
+----------------------+----------------------+----------------------+
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Marty R.



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

PostPosted: Sun Nov 11, 2007 6:14 am    Post subject: Reply with quote

Quote:
Marty, if you want to get the puzzle ahead of the time zone, sign up for e-mail!

I figure as soon as I do that, he'll start time-zoning the e-mails!

In the meantime, I'm working on it while watching Hawaii-Fresno St. and not concentrating very well on either. Sure enough, as I'm heading toward completion, I notice the two 5s in column 6, so I erase the whole thing and will start over in the morning. Mad
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andras



Joined: 31 Oct 2007
Posts: 56
Location: Mid Wales

PostPosted: Sun Nov 11, 2007 10:09 am    Post subject: Reply with quote

Nothing to it, really - just a single x-wing to break it wide open.

John
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Asellus



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

PostPosted: Sun Nov 11, 2007 12:07 pm    Post subject: Reply with quote

A single W-Wing does the trick, too.
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cgordon



Joined: 04 May 2007
Posts: 769
Location: ontario, canada

PostPosted: Sun Nov 11, 2007 12:59 pm    Post subject: Reply with quote

Not as simple as an x-wing but there were two similar ERs using R8 and Box 3 that knocked off the <5> and <7> in R2C4. There was also a UR on <14> in C58 that was no use at all - but it was still clever to spot it.
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Marty R.



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

PostPosted: Sun Nov 11, 2007 5:12 pm    Post subject: Reply with quote

Asellus wrote:
A single W-Wing does the trick, too.


Asellus, what W-Wing solved it for you? I used the 57 W-Wing to knock out the 5 from r2c4, but I needed the X-Wing on 7 to solve that same cell and then the puzzle. I'm not sure if my Draw/Play grid is identical to the pencil-and-paper grid I used.

Code:

+--------------+----------------+------------+
| 5  2    8    | 47   9     1   | 3   47   6 |
| 9  137  4    | 78   6     358 | 57  157  2 |
| 67 1367 1367 | 2    3457  35  | 9   1457 8 |
+--------------+----------------+------------+
| 24 8    7    | 145  12345 235 | 14  6    9 |
| 1  46   26   | 9    24    7   | 8   3    5 |
| 3  5    9    | 1468 14    68  | 14  2    7 |
+--------------+----------------+------------+
| 67 9    167  | 1567 1257  4   | 257 8    3 |
| 24 34   23   | 57   8     9   | 6   57   1 |
| 8  167  5    | 3    127   26  | 27  9    4 |
+--------------+----------------+------------+

Play this puzzle online at the Daily Sudoku site
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cgordon



Joined: 04 May 2007
Posts: 769
Location: ontario, canada

PostPosted: Sun Nov 11, 2007 6:01 pm    Post subject: Reply with quote

Quote:
Nothing to it, really - just a single x-wing to break it wide open.


Just out of curiosity - where is the x-wing?
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Johan



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

PostPosted: Sun Nov 11, 2007 7:03 pm    Post subject: Reply with quote

Quote:
Just out of curiosity - where is the x-wing?


X-wing <7> in R18C48

The grid after basic steps :

Code:


+-------------+----------------+------------+
| 5  2    8   | 47   9     1   | 3   47   6 |
| 9  137  4   | 578  6     358 | 57  157  2 |
| 67 1367 136 | 2    3457  35  | 9   1457 8 |
+-------------+----------------+------------+
| 24 8    7   | 145  12345 235 | 14  6    9 |
| 1  46   26  | 9    24    7   | 8   3    5 |
| 3  5    9   | 68   14    68  | 14  2    7 |
+-------------+----------------+------------+
| 67 9    16  | 1567 1257  4   | 257 8    3 |
| 24 34   23  | 57   8     9   | 6   57   1 |
| 8  167  5   | 3    127   26  | 27  9    4 |
+-------------+----------------+------------+
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andras



Joined: 31 Oct 2007
Posts: 56
Location: Mid Wales

PostPosted: Sun Nov 11, 2007 8:05 pm    Post subject: Reply with quote

Oddly enough my wife solved it without using any advanced techniques. She's lucky that way sometimes Smile

John
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Asellus



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

PostPosted: Sun Nov 11, 2007 8:27 pm    Post subject: Reply with quote

Marty wrote:
Asellus, what W-Wing solved it for you?

Hmmm... going back over it, I believe I must have been emmulating John's wife!

Apparently, I thought I saw a resulting locked set that isn't there now. Embarassed
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keith



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

PostPosted: Sun Nov 11, 2007 8:52 pm    Post subject: Reply with quote

The <24> cells R8C1 and R5C5 are W-wings on both <2> and <4>, but I can't find anything useful to do with them!

<57> in R8C4 and R2C7 are a W-wing which takes out <5> in R2C4.

Keith
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re'born



Joined: 28 Oct 2007
Posts: 80

PostPosted: Sun Nov 11, 2007 11:15 pm    Post subject: Reply with quote

keith wrote:

<57> in R8C4 and R2C7 are a W-wing which takes out <5> in R2C4.

If you're careful, you'll notice that this W-wing takes out both the 5 and the 7 from r2c4, which solves the puzzle. Think grouped conjugate links!
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Asellus



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

PostPosted: Mon Nov 12, 2007 3:10 am    Post subject: Reply with quote

re'born wrote:
If you're careful, you'll notice that this W-wing takes out both the 5 and the 7 from r2c4, which solves the puzzle.

Oh! Maybe that's how I did it! Wink
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eddieg



Joined: 12 Jan 2006
Posts: 47
Location: San Diego, CA USA

PostPosted: Mon Nov 12, 2007 4:35 pm    Post subject: A few days late, question! Reply with quote

Code:

+--------------+---------------+-----------+
| 5   2    8   | 47   9    1   | 3   47  6 |
| 9   137  4   | 58   6    358 | 57  15  2 |
| 67  1367 136 | 2    457  35  | 9   145 8 |
+--------------+---------------+-----------+
| 24  8    7   | 145  3    25  | 14  6   9 |
| 1   46   26  | 9    24   7   | 8   3   5 |
| 3   5    9   | 1468 14   68  | 14  2   7 |
+--------------+---------------+-----------+
| 267 9    126 | 156  1257 4   | 257 8   3 |
| 247 347  23  | 57   8    9   | 6   57  1 |
| 8   167  5   | 3    127  26  | 27  9   4 |
+--------------+---------------+-----------+

[url=http://www.dailysudoku.com/sudoku/play.shtml?
p=5:2:8:47:9:1:3:47:6:9:137:4:58:6:358:57:15:2:67:1367:136:2:457:35:9:145:8:24:8:7:145:3:25:14:6:9:1:46:26:9:24:7:8:3:5:3:5:9:1468:14:68:14:2:7:267:9:126:156:1257:4:257:8:3:247:347:23:57:8:9:6:57:1:8:167:5:3:127:26:27:9:4:]Play this puzzle online[/url] at the Daily Sudoku site

This is where I was. I noticed what I thought was a relationship between squares R2C7, the squares in the middle column of Box 3 (R1C8, R2C8, and R3C8), R8C8, and R8C4. I figured that R2C7 was either a 5 or a 7, thus the center column of Box 3 would contain a 5 or a 7, and in this case I could pair up the combinations of 5's and 7's and thus eliminate the 8 from R2C3, and then the puzzle was solved easily.

Was this a correct move?
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cgordon



Joined: 04 May 2007
Posts: 769
Location: ontario, canada

PostPosted: Mon Nov 12, 2007 5:32 pm    Post subject: Reply with quote

Quote:
Was this a correct move?

Hey !!! That's MY ER mentioned above !

See how the 5's in Box 3 form an + shaped hinge (with bits missing). The term Empty Rectangle actually refers to the blank cells in Box 3 that do not contain a 5 and form a rectangle. A misnoma I think - given that it's the bigger rectangle (box 2389) that one looks for. Sorry - just rambling.

Code:
            
+-------+-------+-------+   
| . . . | . . . | . + . |   
| . . . | 5 . . | 5 5 + |   
| . . . | . . . | . 5 . |   
+-------+-------+-------+   
| . . . | . . . | . . . |   
| . . . | . . . | . . . |   
| . . . | . . . | . . . |   
+-------+-------+-------+   
| . . . | . . . | . . . |   
| . . . | 5 . . | . 5 . |   
| . . . | . . . | . . . |
+-------+-------+-------+
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George Woods



Joined: 28 Mar 2006
Posts: 304
Location: Dorset UK

PostPosted: Mon Nov 12, 2007 10:01 pm    Post subject: Reply with quote

cgordon wrote:
Quote:
Was this a correct move?

Hey !!! That's MY ER mentioned above !

See how the 5's in Box 3 form an + shaped hinge (with bits missing). The term Empty Rectangle actually refers to the blank cells in Box 3 that do not contain a 5 and form a rectangle. A misnoma I think - given that it's the bigger rectangle (box 2389) that one looks for. Sorry - just rambling.

Code:
            
+-------+-------+-------+   
| . . . | . . . | . + . |   
| . . . | 5 . . | 5 5 + |   
| . . . | . . . | . 5 . |   
+-------+-------+-------+   
| . . . | . . . | . . . |   
| . . . | . . . | . . . |   
| . . . | . . . | . . . |   
+-------+-------+-------+   
| . . . | . . . | . . . |   
| . . . | 5 . . | . 5 . |   
| . . . | . . . | . . . |
+-------+-------+-------+


Am I correct in thinking that for the example of ER to work one of the
pairs of 5 in a line must be a pair- In the puzzle (as far as I remember) from which the example derives it was row 8 that had just two 5s. and whichever one is 5 it either kills the 5 in r2c4 directly , or via box 3! ?
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Steve R



Joined: 24 Oct 2005
Posts: 289
Location: Birmingham, England

PostPosted: Tue Nov 13, 2007 3:22 pm    Post subject: Reply with quote

Yes.

As far as I know the structure was first described on on 25 December 2005 by Rod Hagglund. He called it a “hinge.”

It was subsequently described again by Havard, who rechristened it "empty rectangle."

Steve
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