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One from Keith

 
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keith



Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
PostPosted: Sun Dec 16, 2007 7:11 pm    Post subject: One from Keith Reply with quote
Marty will understand why I must post this one:

Code:
Puzzle: M5121370sh(12)
+-------+-------+-------+
| . 7 5 | . 2 . | 1 3 . |
| . 3 6 | . . . | 4 5 . |
| . . . | . . 8 | . . . |
+-------+-------+-------+
| . 4 8 | . 3 . | . . . |
| . 6 . | 4 . 7 | . 8 . |
| . . . | . 8 . | 5 4 . |
+-------+-------+-------+
| . . . | 9 . . | . . . |
| . 9 3 | . . . | 8 6 . |
| . 5 7 | . 6 . | 3 9 . |
+-------+-------+-------+



Best wishes,

Keith
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ravel



Joined: 21 Apr 2006
Posts: 536
PostPosted: Sun Dec 16, 2007 8:38 pm    Post subject: Reply with quote
Nice puzzle. I saw a combination of kite and w-wing here (but probably you mean something else), then x-, xy-wing.
Code:
 *-----------------------------------------------------------*
 | 89    7     5     | 6     2     4     | 1     3     89    |
 | 28    3     6     | 17    179   19    | 4     5     28    |
 | 1249  12    124   | 3     5     8     | 2679  27    269   |
 |-------------------+-------------------+-------------------|
 | 7     4     8     | 25    3     259   | 269   12    1269  |
 | 5     6     12    | 4     19    7     | 29    8     3     |
 | 3     12    9     | 12    8     6     | 5     4     7     |
 |-------------------+-------------------+-------------------|
 | 6     8     124   | 9     14    3     | 27    127   5     |
 | 124   9     3     | 1257  147   125   | 8     6     124   |
 | 124   5     7     | 8     6     12    | 3     9     124   |
 *-----------------------------------------------------------*
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keith



Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
PostPosted: Sun Dec 16, 2007 9:45 pm    Post subject: Reply with quote
Ravel,

We must have made similar eliminations, because my ending seems to be similar to yours

Warning: Detailed solution below!

Here is my grid. I think it is exactly the same as yours.
Code:
+----------------+----------------+----------------+
| 89   7    5    | 6    2    4    | 1    3    89   |
| 28   3    6    | 17   179  19   | 4    5    28   |
| 1249 12a  124  | 3    5    8    |-2679 -27  269  |
+----------------+----------------+----------------+
| 7    4    8    | 25   3    259  | 269  12   1269 |
| 5    6    12   | 4    19b  7    | 29c  8    3    |
| 3    12A  9    | 12a  8    6    | 5    4    7    |
+----------------+----------------+----------------+
| 6    8    124  | 9    14   3    |-27   127  5    |
| 124  9    3    | 1257 147  125  | 8    6    124  |
| 124  5    7    | 8    6    12   | 3    9    124  |
+----------------+----------------+----------------+

R37C78 is a Type 6 UR (Unique X-wing) on <27>. To avoid the deadly pattern, R3C8 and R7C7 must be <7> (neither can be <2>).

There are two other unique UR's on <25> and on <17>, but those eliminations seem not to help.

Following yesterday's discussion, I was looking for extended wings.

abc is a flightless XY-wing, it makes no eliminations. But, a R6C4 can be extended to R3C2 a-A-a, and <2> is eliminated in R3C7.

From there you get to an X-wing on <1> which makes eliminations in C35, and then an XY-wing that solves R6C4 as <2> finishes it off.

I agree, "nice puzzle". Probably, others will find other ways to solve it.

Ravel, I'd be interested in the details of what you did.

Keith
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Marty R.



Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
PostPosted: Mon Dec 17, 2007 1:12 am    Post subject: Reply with quote
Quote:
Marty will understand why I must post this one:

Because of the URs?

I played an unhelpful XY-Wing on 19-29-12. There seemed to be many potential W-Wings, but I couldn't find a connection. Relatively late in the game I noticed the Type 6, which was more helpful than most that I come across. After that there was a Type 2 on 14 followed by a Type 1 on 69. It's been quite awhile since I solved a puzzle with only URs.
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keith



Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
PostPosted: Mon Dec 17, 2007 1:41 am    Post subject: Reply with quote
Yes, Marty

I am not sure of your path through this puzzle, but I found it to be one of those rarely helpful Type 6 UR's.

Plus, the extended XY-wing.

Keith
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storm_norm



Joined: 18 Oct 2007
Posts: 1741
PostPosted: Mon Dec 17, 2007 3:19 am    Post subject: Reply with quote
finding the xy-wing was the key because it opened the UR on {2,7}

then that led to the UR on {6,9}

Norm
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Asellus



Joined: 05 Jun 2007
Posts: 865
Location: Sonoma County, CA, USA
PostPosted: Mon Dec 17, 2007 4:53 am    Post subject: Reply with quote
I, too, started with that Type 6 {27} UR. But next, I noticed a potential 6-cell DP in the bottom floor, marked @ below:
Code:
+-------------+---------------+--------------+
| 89   7  5   | 6    2    4   | 1   3   89   |
| 28   3  6   | 17   179  19  | 4   5   28   |
| 1249 12 124 | 3    5    8   | 269 7   269  |
+-------------+---------------+--------------+
| 7    4  8   | 25   3    259 | 269 12  1269 |
| 5    6  12  | 4    19   7   | 29  8   3    |
| 3    12 9   | 12   8    6   | 5   4   7    |
+-------------+---------------+--------------+
| 6    8  124 | 9    14   3   | 7   12  5    |
|@124  9  3   | 1257 147 @125 | 8   6  @124  |
|@124  5  7   | 8    6   @12  | 3   9  @124  |
+-------------+---------------+--------------+

The only way to prevent the DP is if r8c6 is <5>.

There is also a Kite, pivoting in box 6, that eliminates <2> from r7c3 (probably the one ravel saw).

After that, a Type 1 {69} UR in r34c79 finishes things off.
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ravel



Joined: 21 Apr 2006
Posts: 536
PostPosted: Mon Dec 17, 2007 9:39 am    Post subject: Reply with quote
Nice find, Asellus.
keith wrote:
Ravel, I'd be interested in the details of what you did.
Code:
*-----------------------------------------------------------*
 | 89    7     5     | 6     2     4     | 1     3     89    |
 | 28    3     6     | 17    179   19    | 4     5     28    |
 | 1249 @12    124   | 3     5     8     | 2679 #27    269   |
 |-------------------+-------------------+-------------------|
 | 7     4     8     | 25    3     259   | 269   12    1269  |
 | 5     6    @12    | 4     19    7     |@29    8     3     |
 | 3    @12    9     | 12    8     6     | 5     4     7     |
 |-------------------+-------------------+-------------------|
 | 6     8     124   | 9     14    3     |#27    127   5     |
 | 124   9     3     | 1257  147   125   | 8     6     124   |
 | 124   5     7     | 8     6     12    | 3     9     124   |
 *-----------------------------------------------------------*
I saw the kite marked @, that takes out 2 from r3c7 (either r3c2 or r5c7 is 2). At the same time it says that one of the 27's has to be 7 (which gives the same as the UR elimination)
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