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Puzzle 10/04/13 ___ BBDB

 
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daj95376



Joined: 23 Aug 2008
Posts: 3854
PostPosted: Tue Apr 13, 2010 8:40 pm    Post subject: Puzzle 10/04/13 ___ BBDB Reply with quote
Code:
 +-----------------------+
 | . . . | . . . | 2 . . |
 | . 1 . | 7 . 6 | . . . |
 | . . 9 | . 2 . | 3 7 . |
 |-------+-------+-------|
 | . 9 . | . . . | 5 . . |
 | . . 1 | . 5 . | . 3 . |
 | . 3 . | . . 9 | . . 7 |
 |-------+-------+-------|
 | 1 . 2 | 6 . . | 8 . 3 |
 | . . 5 | . 3 . | . 1 2 |
 | . . . | . . 2 | 6 9 . |
 +-----------------------+

Play this puzzle online at the Daily Sudoku site
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Mogulmeister



Joined: 03 May 2007
Posts: 1151
PostPosted: Wed Apr 14, 2010 7:46 am    Post subject: Reply with quote
Quote:
Two steps for this toughie:

1)A powerful UR at r58c46 which starts the damage by showing that r5c6 must be 7.

2)Another x chain/colouring idea on 4s which shows up a contradiction.

(8=4)r3c2-r3c6=r12c5-r6c5=r6c3-r9c3=r9c2-(4)r3c2 so r3c2 <>4

If you prefer to see this diagrammatically there is a tinypic url below.

Let green = "is 4" and orange = "not 4" this puts two 4s in column 2 so therefore r3c2 <> 4. Puzzle implodes.

http://i44.tinypic.com/34qwfoz.png


Last edited by Mogulmeister on Wed Apr 14, 2010 8:58 am; edited 1 time in total
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peterj



Joined: 26 Mar 2010
Posts: 974
Location: London, UK
PostPosted: Wed Apr 14, 2010 8:08 am    Post subject: Reply with quote
Took me a bunch of moves! Lots of variety..

Quote:
Type 1 UR(48); r5c6=7
Kite(8); r6c5<>8
x-wing(6); r14c19<>6
xy-wing(468); r4c56<>4
Multi-colour wrap(4); r3c2<>4, r9c3<>4
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tlanglet



Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
PostPosted: Wed Apr 14, 2010 4:00 pm    Post subject: Reply with quote
type 1 UR48 in r58c46 forces r5c6=7,

Looking at the 4s in column 6 we see that r3c6=4 or r48c6=4
(4)r48c6 = (4)r3c6
||
(4)r4c6 - r6c5 = r6c3 - r9c3 = (4)r9c2; r3c2<>4
||
(4)r8c6 - r8c4 = r5c4 - r6c5 = r6c3 - r9c3 = (4)r9c2; r3c2<>4
Thus r3c2<>4 to complete the puzzle.

Ted
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Mogulmeister



Joined: 03 May 2007
Posts: 1151
PostPosted: Wed Apr 14, 2010 4:03 pm    Post subject: Reply with quote
Yep same as mine.
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tlanglet



Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
PostPosted: Wed Apr 14, 2010 4:04 pm    Post subject: Reply with quote
Mogulmeister wrote:
Quote:
Two steps for this toughie:

1)A powerful UR at r58c46 which starts the damage by showing that r5c6 must be 7.

2)Another x chain/colouring idea on 4s which shows up a contradiction.

(8=4)r3c2-r3c6=r12c5-r6c5=r6c3-r9c3=r9c2-(4)r3c2 so r3c2 <>4

If you prefer to see this diagrammatically there is a tinypic url below.

Let green = "is 4" and orange = "not 4" this puts two 4s in column 2 so therefore r3c2 <> 4. Puzzle implodes.

http://i44.tinypic.com/34qwfoz.png


I did not read your post until after I posted my own solution. We had the same path essentially, but yours is definitely cleaner; good solution

Ted
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Mogulmeister



Joined: 03 May 2007
Posts: 1151
PostPosted: Wed Apr 14, 2010 5:05 pm    Post subject: Reply with quote
Hi Ted
I didn't mean it that way....I was trying to say that obviously a lot of the good stuff you and Norm are doing is rubbing off if we're converging on the similar solutions !
Smile

Last edited by Mogulmeister on Wed Apr 14, 2010 7:53 pm; edited 1 time in total
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Luke451



Joined: 20 Apr 2008
Posts: 310
Location: Southern Northern California
PostPosted: Wed Apr 14, 2010 6:08 pm    Post subject: Reply with quote
There is a subtle difference, not that important to me, but a big issue to some.

Ted's net requires the interaction of three assumptions:
-if r3c6 is (4) then r3c2 cannot be (4)
-if r4c6 is (4) then r3c2 cannot be (4)
-if r8c6 is (4) then r3c2 cannot be (4)

The AIC used by the Master of the Moguls is a series of statements, and it makes no assumptions.

Some players feel if they have a choice, it's better to not make any assumptions.
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Mogulmeister



Joined: 03 May 2007
Posts: 1151
PostPosted: Wed Apr 14, 2010 7:52 pm    Post subject: Reply with quote
Luke, the a priori argument if I'm not mistaken ?
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tlanglet



Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
PostPosted: Thu Apr 15, 2010 2:14 am    Post subject: Reply with quote
I agree Luke. That is why I indicated a preference for MMs solution.

Ted
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Marty R.



Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
PostPosted: Thu Apr 15, 2010 8:20 pm    Post subject: Reply with quote
I did my typical twice as many moves, using eight of them, including various types of wings, URs and ending with multi-coloring.
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