The New Sudoku Players' Forum

[wmarshall]

I am consistently able to solve the 5-star puzzles that appear on Sunday in my newspaper. However, this one is the exception. All I'm looking for is the next play and how it is located. Any help would be appreciated.

Code: Select all

                 
                            6   8   3
     6        5            4   9   2
         9          4      5   7   1

     4        1            3
                  4
         8          3           5

  5           2            9
  1                 8           3
     9  6

[JasonLion]

It is very difficult to tell exactly what the original puzzle you are trying to post might be. You should use '.' to represent empty cells instead of spaces. Otherwise the spaces between cells run together with the spaces in empty cells and it is difficult to tell what is what.

The closest I can come is perhaps:

Code: Select all

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

[wmarshall]

You have it correct, except there is a 4 in the extreme right column in the sixth block from the bottom. In addition to that 4, the only plays I have made are in the top right box (3,4,9,5,7). All other numbers were given with the puzzle.

Basically, what I am hoping you can help with is the next play and the reasoning behind it.

Thanks,

Bill Marshall

[JasonLion]

There is a naked pair in row 8, and then singles to the end.

Code: Select all

247    1257   12457  | 79     1279   1279   | 6      8      3     
378    6      137    | 5      1378   17     | 4      9      2     
238    238    9      | 368    2368   4      | 5      7      1     
---------------------+----------------------+---------------------
2679   4      257    | 1      256789 25679  | 3      26     6789 
23679  12357  12357  | 6789   4      25679  | 1278   126    6789 
2679   127    8      | 679    2679   3      | 127    5      4     
---------------------+----------------------+---------------------
5      378    347    | 2      1367   167    | 9      146    678   
1      27     247    | 4679   5679   8      | 27     3      567   
23478  9      6      | 347    1357   157    | 1278   124    578 

R8C2 and R8C7 can both only contain 2 or 7, that means that together they must contain 2 and 7 (though we don't know which goes in which cell). That allows us to eliminate 2 and 7 from all cells which see both of those. That immediately results in placing a 4 in R8C3.

[wmarshall]

Thanks, very much. I understand naked pairs, but just didn't work R8C2 down to the 2 and 7. I do appreciate your help.