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Puzzle 10/02/07 gM-Wing

 
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daj95376



Joined: 23 Aug 2008
Posts: 3854

PostPosted: Sun Feb 07, 2010 6:07 pm    Post subject: Puzzle 10/02/07 gM-Wing Reply with quote

In case you find some spare time. (Rated XY.)

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

Play this puzzle online at the Daily Sudoku site
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tlanglet



Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills

PostPosted: Sun Feb 07, 2010 11:37 pm    Post subject: Reply with quote

I used three steps for this puzzle.

Quote:
xy-wing 2-37 with vertex 27 in r2c6.
Kraken x-wing 7 in r29c67 with fin in r9c2: (9)r9c2 - r9c6 = r78c4 - r4c4 = r6c5; r6c7<>7,
flightless xy-wing 35-7 with vertex 35 in r6c7, pincer 57 in r6c8 and pincer 37 a pseudocell in r23c7 with pincer transport: (7)r2c7 - r2c6 = r1c5; r6c5<>7.


Ted
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Marty R.



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

PostPosted: Tue Feb 09, 2010 12:15 am    Post subject: Reply with quote

I used perhaps seven steps, depending on what counts as a step. The puzzle is labeled gM-Wing, although I didn't use one. However, an M-Wing with pincer transport was critical in setting up my ending moves of looking at the implications of a 79 UR.
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daj95376



Joined: 23 Aug 2008
Posts: 3854

PostPosted: Wed Feb 10, 2010 5:08 pm    Post subject: Reply with quote

Two steps: XY-Wing and gM-Wing.

Code:
 r16\c59 finned  X-Wing                  <> 7    r4c9        extraneous
 r2c5    2-String Kite                   <> 7    r6c7        extraneous

   c67   X-Wing                          <> 7    r9c248      extraneous

 <37+2>  XY-Wing  r1c5/r2c6+r5c5         <> 2    r3c5,r5c6
 <27+3>  XY-Wing  r2c6/r1c5+r5c6         <> 3    r5c5        extraneous

 gM-Wing: (3=4)r3c5 - r6c5 = (4-3)r6c9 = (3)r1c9  =>  r1c5,r3c7<>3
 +-----------------------------------------------------+
 |  2    4    9    |  8    37   5    |  1    6    37   |
 |  6    5    3    |  9    1    27   |  27   4    8    |
 |  7    1    8    |  24   34   6    |  23   9    5    |
 |-----------------+-----------------+-----------------|
 |  9    3    5    |  47   8    1    |  6    27   24   |
 |  4    6    7    |  5    2    3    |  9    8    1    |
 |  1    8    2    |  6    47   9    |  35   57   347  |
 |-----------------+-----------------+-----------------|
 |  5    279  16   |  127  69   4    |  8    3    279  |
 |  3    279  16   |  127  569  8    |  4    257  279  |
 |  8    29   4    |  3    59   27   |  57   1    6    |
 +-----------------------------------------------------+
 # 38 eliminations remain
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Marty R.



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

PostPosted: Wed Feb 10, 2010 5:41 pm    Post subject: Reply with quote

Couple of questions.

1. I know these terms are not definitive, but would you say that gM-Wings occur often, seldom, rarely or something else?

2. Is there some way of looking for them that is more efficient than looking at dozens of cells?
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daj95376



Joined: 23 Aug 2008
Posts: 3854

PostPosted: Wed Feb 10, 2010 6:27 pm    Post subject: Reply with quote

Marty R. wrote:
Couple of questions.

1. I know these terms are not definitive, but would you say that gM-Wings occur often, seldom, rarely or something else?

2. Is there some way of looking for them that is more efficient than looking at dozens of cells?

This is only my opinion based on very limited experience with gM-Wings. I hope others will add their opinion as well.

1) I think gM-Wings occur often ... but are seldom found. Often, when a gM-Wing is present, an easier-to-find W-Wing is also present. When you have a case like this puzzle where there is only one productive gM-Wing present, it makes the puzzle extremely difficult to solve. Hence, the reason I added the gM-Wing warning to the title.

2) I don't know of any reasonable way to spot them; but, then again, I probably couldn't find an XYZ-Wing if my life depended upon it. Hence, the reason I add an alert to the body of puzzles with an XYZ-Wing.

Bottom Line: I previously announced that I was going to stop posting puzzles with gM-Wings. Arkietech/Dan mentioned something about wanting the puzzles to continue so he could practice looking for gM-Wings. Since (to me recollection) no one has supplied a gM-Wing solution to puzzles since Dan's comment, I'm going back to my original position.

This is the last puzzle of mine that needs a gM-Wing. If you'd like another gM-Wing to solve, send me a private message. They also appear to be a great source of puzzles that can be solved by any number of chains; i.e., a chain-rich environment.

Regards, Danny
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Marty R.



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

PostPosted: Wed Feb 10, 2010 8:29 pm    Post subject: Reply with quote

Thanks for the response. Like Dan, I wouldn't mind getting in some practice in looking for them, especially if they occur fairly often.
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arkietech



Joined: 31 Jul 2008
Posts: 1834
Location: Northwest Arkansas USA

PostPosted: Wed Feb 10, 2010 10:29 pm    Post subject: Reply with quote

daj95376 wrote:
Arkietech/Dan mentioned something about wanting the puzzles to continue so he could practice looking for gM-Wings. Since (to me recollection) no one has supplied a gM-Wing solution to puzzles since Dan's comment,

I am still looking! My problem is I find something to solve the puzzle before I get to your wing. Sad I like your puzzles -- keep them coming.
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