Post the puzzle or solving technique that's causing you trouble and someone will help

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     1612678  28     1278  |126    3      12678 |9      5      4126    235    4     |12569  2569   1256  |23     8      7--------------------------------------------------------------9      6      12    |8      4      12    |7      3      5128    28     5     |7      26     3     |4      16     94      7      3     |156    56     9     |8      2      16--------------------------------------------------------------5      1      278   |249    2789   278   |6      479    33      9      6     |24     1      278   |5      47     28278    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

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
2013 Supporter

Posts: 475
Joined: 13 January 2008

Thanks I don't know how that pair eluded me.
JeJ

Posts: 76
Joined: 06 January 2011

### re: "Challenger" puzzle

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

Pat

Posts: 3690
Joined: 18 July 2005

### Re: re: "Challenger" puzzle

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