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Puzzle 11/03/15: ~ Extreme

 
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daj95376



Joined: 23 Aug 2008
Posts: 3854
PostPosted: Tue Mar 15, 2011 7:02 pm    Post subject: Puzzle 11/03/15: ~ Extreme Reply with quote
Code:
 +-----------------------+
 | . 3 . | . 9 . | . . . |
 | 8 . 1 | 3 6 . | 2 . . |
 | . 9 6 | 2 4 . | . . . |
 |-------+-------+-------|
 | . 6 7 | 9 . . | . . 2 |
 | 3 1 2 | . 7 . | 9 . 6 |
 | . . . | . . . | 7 3 . |
 |-------+-------+-------|
 | . 7 . | . 5 9 | 6 . 3 |
 | . . . | . . 7 | . . . |
 | . . . | 4 3 . | 8 . . |
 +-----------------------+

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peterj



Joined: 26 Mar 2010
Posts: 974
Location: London, UK
PostPosted: Wed Mar 16, 2011 8:28 am    Post subject: Reply with quote
Interesting almost-move which oddly was discussed recently elsewhere on this forum. The cell r4c7 is the pincer for two almost xy-wings. The first is xy-wing(18-5) pivot r4c5 and pincers r4c7, r5c4 and the second is xy-wing(14-5) pivot r1c7 and pincers r3c8, r4c7. They both eliminate (5)r5c8.
I'd be tempted to notate it like this for maximum impact!
Code:
xy-wing(18-5)[(5=8)r5c4-(8=1)r4c5-(1=5)r4c7]=xy-wing(14-5)[(5=4)r4c7-(4=1)r1c7-(1=5)r3c8] ; r5c8<>5

Of course you could write one of the two conventional almost xy-wings or indeed treat r4c7 as a Kraken cell.
After that...
Code:
kite(5) r6, c7 ; r8c2<>5
xy-wing(12-8) r8c5 ; r7c3<>8, r8c4<>8
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daj95376



Joined: 23 Aug 2008
Posts: 3854
PostPosted: Wed Mar 16, 2011 2:29 pm    Post subject: Reply with quote
Peter,

While reviewing you almost XY-Wing pair, I realized that it also contains an XY-Chain with fin( r4c7=5 ) that results in your elimination, r5c8<>5.

Code:
 XY-Chain: (5=1)r3c8 =4r1c7 =1r4c7 =8r4c5 =5r5c4  =>  r5c8<>5
 fin:      (5)r4c7                                =>  r5c8<>5
 +--------------------------------------------------------------+
 |  2     3     5     |  7     9     18    | b14    6     148   |
 |  8     4     1     |  3     6     5     |  2     79    79    |
 |  7     9     6     |  2     4     18    |  3    a15    158   |
 |--------------------+--------------------+--------------------|
 |  45    6     7     |  9    d18    3     | c14+5  1458  2     |
 |  3     1     2     | e58    7     4     |  9     8-5   6     |
 |  9     58    48    |  156   12    26    |  7     3     145   |
 |--------------------+--------------------+--------------------|
 |  14    7     48    |  18    5     9     |  6     2     3     |
 |  156   258   3     |  168   128   7     |  145   1459  1459  |
 |  156   25    9     |  4     3     26    |  8     157   157   |
 +--------------------------------------------------------------+
 # 54 eliminations remain
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Marty R.



Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
PostPosted: Wed Mar 16, 2011 4:43 pm    Post subject: Reply with quote
I used:

Xy-Wing (158), flightless
Type 4 UR (18)
AIC
W-Wing (45)
BUG+1
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