Need help with puzzle #239 from Su Doku for Dummies

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Need help with puzzle #239 from Su Doku for Dummies

Postby ATL30 » Mon Dec 31, 2007 4:41 am

I am stuck on this puzzle is from the diabolical section. I can not figure out the next move. Can it be solved without a computer program?

Code: Select all
68 | 4    | 7    | 5    | 39 | 1     | 3689  | 368 | 2
5  | 1    | 368  | 3689 | 2  | 36789 | 4     | 368 | 36789
9  | 268  | 2368 | 368  | 4  | 3678  | 36789 | 1   | 5
7  | 3    | 689  | 69   | 5  | 2     | 1     | 4   | 68
1  | 2689 | 2689 | 7    | 39 | 4     | 2368  | 5   | 368
4  | 256  | 256  | 1    | 8  | 36    | 2367  | 9   | 367
2  | 7    | 589  | 4    | 6  | 3589  | 389   | 38  | 1
68 | 5689 | 1    | 389  | 7  | 3589  | 3689  | 2   | 4
3  | 689  | 4    | 2    | 1  | 89    | 5     | 7   | 689



Thanks in advance for any help.
ATL30
 
Posts: 2
Joined: 30 December 2007

Postby daj95376 » Mon Dec 31, 2007 9:21 am

Code: Select all
+-----------------------------------------------------------------------------+
|  68      4       7      |  5       39      1      |  3689    368     2      |
|  5       1       368    |  3689    2       36789  |  4       368     36789  |
|  9       268     2368   |  368     4       3678   |  36789   1       5      |
|-------------------------+-------------------------+-------------------------|
|  7       3       689    |  69      5       2      |  1       4       68     |
|  1       2689    2689   |  7       39      4      |  2368    5       368    |
|  4       256     256    |  1       8       36     |  2367    9       367    |
|-------------------------+-------------------------+-------------------------|
|  2       7       589    |  4       6       3589   |  389     38      1      |
|  68      5689    1      |  389     7       3589   |  3689    2       4      |
|  3       689     4      |  2       1       89     |  5       7       689    |
+-----------------------------------------------------------------------------+

Although there's a Locked Candidate (2) in [c8b3] for <6>, it doesn't help. Other than that, a contradiction chain is the best I have to offer. It took my solver to find it.

Code: Select all
[r5c5]=3 =>[r1c5]=9 => [r2c9]=9 => [r459c9]={68} contradiction! => [r5c5]=9

Singles then complete the puzzle.

You might wish to look at these links for further discussions on this puzzle.

http://forum.enjoysudoku.com/viewtopic.php?p=39630#p39630
http://forum.enjoysudoku.com/viewtopic.php?p=41461#p41461
daj95376
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Posts: 2624
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Postby ATL30 » Mon Dec 31, 2007 7:10 pm

Thanks daj95376!

Will followup on those links to see what else I've missed.
ATL30
 
Posts: 2
Joined: 30 December 2007


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