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keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
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 Posted: Sun Nov 11, 2007 3:44 am Post subject: Nov 11 VH |
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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
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| Posted: Sun Nov 11, 2007 6:14 am Post subject: |
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| 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.  |
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andras
Joined: 31 Oct 2007
Posts: 56
Location: Mid Wales
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| Posted: Sun Nov 11, 2007 10:09 am Post subject: |
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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
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| Posted: Sun Nov 11, 2007 12:07 pm Post subject: |
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| A single W-Wing does the trick, too. |
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cgordon
Joined: 04 May 2007
Posts: 769
Location: ontario, canada
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| Posted: Sun Nov 11, 2007 12:59 pm Post subject: |
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| 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
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| Posted: Sun Nov 11, 2007 5:12 pm Post subject: |
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| 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 |
+--------------+----------------+------------+
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Play this puzzle online at the Daily Sudoku site |
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cgordon
Joined: 04 May 2007
Posts: 769
Location: ontario, canada
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| Posted: Sun Nov 11, 2007 6:01 pm Post subject: |
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| Quote: | Nothing to it, really - just a single x-wing to break it wide open.
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Just out of curiosity - where is the x-wing? |
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Johan
Joined: 25 Jun 2007
Posts: 206
Location: Bornem Belgium
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| Posted: Sun Nov 11, 2007 7:03 pm Post subject: |
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| 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
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| Posted: Sun Nov 11, 2007 8:05 pm Post subject: |
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Oddly enough my wife solved it without using any advanced techniques. She's lucky that way sometimes 
John |
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Asellus
Joined: 05 Jun 2007
Posts: 865
Location: Sonoma County, CA, USA
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| Posted: Sun Nov 11, 2007 8:27 pm Post subject: |
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| 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.  |
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keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
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| Posted: Sun Nov 11, 2007 8:52 pm Post subject: |
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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
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| Posted: Sun Nov 11, 2007 11:15 pm Post subject: |
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| keith wrote: |
<57> in R8C4 and R2C7 are a W-wing which takes out <5> in R2C4.
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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
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| Posted: Mon Nov 12, 2007 3:10 am Post subject: |
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| 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!  |
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eddieg
Joined: 12 Jan 2006
Posts: 47
Location: San Diego, CA USA
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| Posted: Mon Nov 12, 2007 4:35 pm Post subject: A few days late, question! |
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| 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 |
+--------------+---------------+-----------+
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[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
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| Posted: Mon Nov 12, 2007 5:32 pm Post subject: |
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| 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
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| Posted: Mon Nov 12, 2007 10:01 pm Post subject: |
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| 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 . |
| . . . | . . . | . . . |
+-------+-------+-------+
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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
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| Posted: Tue Nov 13, 2007 3:22 pm Post subject: |
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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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