Challenger Sudoku #3 or 4 I ask about

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Challenger Sudoku #3 or 4 I ask about

Postby JeJ » Sun Jan 16, 2011 11:12 pm

Hi again

I have this game that starts as:
Code: Select all
. . 9|. . 4|. . .
. . .|. 3 .|9 5 .
. . 4|. . .|. 8 7
-----------------
. 6 .|8 . .|. 3 5
. . .|7 . 3|. . .
4 7 .|. . 9|. 2 .
-----------------
5 1 .|. . .|6 . .
. 9 6|. 1 .|. . .
. . .|3 . .|1 . .


Which I have been able to get to (including a cell with 6 pencilmarks, something that hadn't happened to me before):
Code: Select all
12678  2358   9     |1256   25678  4     |23     16     16
12678  28     1278  |126    3      12678 |9      5      4
126    235    4     |12569  2569   1256  |23     8      7
--------------------------------------------------------------
9      6      12    |8      4      12    |7      3      5
128    28     5     |7      26     3     |4      16     9
4      7      3     |156    56     9     |8      2      16
--------------------------------------------------------------
5      1      278   |249    2789   278   |6      479    3
3      9      6     |24     1      278   |5      47     28
278    4      278   |3      256789 25678 |1      79     28


I have tried to force some chains whithout any luck. So could someone give me a hint on how should I procede?
Thanks.
JeJ
 
Posts: 76
Joined: 06 January 2011

Re: Challenger Sudoku #3 or 4 I ask about

Postby DonM » Mon Jan 17, 2011 12:02 am

To get you started: There's a naked pair (16) or locked 1s and 6s in r1c89 ( depending on how you want to look at it) so you can remove all 1s and 6s in the rest of row 1. Likewise there's a naked pair (28) in r25c2 so you can remove all other 2s and 8s in column 2. Of interest is the fact that there is a naked quintuple in box 1 (12678) which accomplishes the same thing as the naked pair (28) last mentioned.

There's a naked quintuple (12569) in box 2 so you can remove the 1256s that occur in that box outside of the quintuple.
DonM
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Re: Challenger Sudoku #3 or 4 I ask about

Postby JeJ » Mon Jan 17, 2011 1:29 am

Thanks I don't know how that pair eluded me.
JeJ
 
Posts: 76
Joined: 06 January 2011

re: "Challenger" puzzle

Postby Pat » Tue Jan 18, 2011 8:22 am

JeJ wrote:
Code: Select all

 . . 9 | . . 4 | . . .
 . . . | . 3 . | 9 5 .
 . . 4 | . . . | . 8 7
-------+-------+------
 . 6 . | 8 . . | . 3 5
 . . . | 7 . 3 | . . .
 4 7 . | . . 9 | . 2 .
-------+-------+------
 5 1 . | . . . | 6 . .
 . 9 6 | . 1 . | . . .
 . . . | 3 . . | 1 . .



nice puzzle

    ( where do these "Challenger" puzzles come from ? )

my path --
    in r9, "hidden" duo {5,6}
    now in c5, "hidden" duo {7,8}
    this solves the 9s for c5 and for b8
total = 2 moves
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Pat
 
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Re: re: "Challenger" puzzle

Postby JeJ » Tue Jan 18, 2011 5:09 pm

Pat wrote:
JeJ wrote:[size=130]

nice puzzle[list]

( where do these "Challenger" puzzles come from ? )

They are from a magazine called "World Sudoku" edited by penny press www.pennypress.com and this specific one is from the Spring 2007 issue.
JeJ
 
Posts: 76
Joined: 06 January 2011


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