Another difficult on (for me)

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Another difficult on (for me)

Postby Jackie78 » Fri Nov 14, 2008 10:59 pm

Hi,

I am still learning, trying to solve some "hard" sudokus, this is how far I've gone, but I have no clue how to continue. Any help is appreciated:)

Code: Select all
289   7      29   | 1     3      59    | 4     58     6
3     69     5    | 4789  46     679   | 2     78     1
68    4      1    | 578   2      567   | 57    3      9
------------------+--------------------+-------------------
24    235    234  | 25_7_ 8      1     | 6     9      47
2469  2569   2469 | 257   57     3     | 8     1      47
7     1      8    | 49    46     69    | 3     2      5
------------------+--------------------+-------------------
469   69     4679 | 3     19     28    | 157   57     28
1     8      23   | 57    57     4     | 9     6      23
5     239    2379 | 6     19     28    | 17    4      238


Source: http://www.denksport.de/braingymnastik/sudoku/default.asp?l=4&a=3

Thanks alot.
Last edited by Jackie78 on Sat Nov 15, 2008 6:54 pm, edited 3 times in total.
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Postby re'born » Fri Nov 14, 2008 11:26 pm

Try to determine where 7 can go in row 4. After that, look for a naked pair in column 2.

For those with more background, note the UR1 that places a 2 in r5c4, immediately reducing the puzzle to singles.
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Postby Jackie78 » Sat Nov 15, 2008 10:37 pm

Hello reborn,

sorry there was a typo in my pencilmarks in r4c4, I have a 7 instead of a 6 here, do you have another hint how to solve it?
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Postby tarek » Sun Nov 16, 2008 12:29 am

all the 5s & 7s in Column 6 are also confined to box 2 ...

This means that the 5s & 7s are locked in that intersection (column 6 & box 2)...

Therefore you can safely eliminate 5 & 7 (box 2 but outside the above intersection) from r3c4 leaving a naked single there.

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