The New Sudoku Players' Forum

[sudophil]

I'm to my limit with this one. I can't tell from topics if it as been addressed before. I suggest the sticky should advise everyone to give puzzle's first 5 numbers in the topic.

I filled in as far as I could go. The original puzzle first 5 numbers are as I indicated.

Original is from Journal World 6/23/06

Code: Select all

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


[underquark]

Fill in the candidates (possibilities for each cell). You will see many pairs and triples scattered throughout this paricular puzzle.

Consider Box1:

Code: Select all

2349     1        29
7        8        269
3469     69       5

2, 6 and 9 can only exist in a certain 3 cells and can thus be excluded from other cells in that box:

Code: Select all

34       1        29
7        8        269
34       69       5

Now note that there has to be a 2 somewhere in Box1 and it has to be in the 3rd column. This excludes 2s from anywhere else further down in that column.

[TKiel]

Sudophil,

Singles, locked candidates and naked triples/hidden pairs gets you to this point:

Code: Select all

 
 *-----------------------------------------------------------*
 | 4     1     9     | 3     7     5     | 8     6     2     |
 | 7     8     2     | 46    9     46    | 5     1     3     |
 | 3     6     5     | 8     2     1     | 7     9     4     |
 |-------------------+-------------------+-------------------|
 | 1     4     67    | 9     8     2     | 3     5     67    |
 | 9     57    8     | 167   356   367   | 4     2     167   |
 | 56    2     3     | 1467  56    467   | 16    8     9     |
 |-------------------+-------------------+-------------------|
 | 56    57    4     | 67    1     9     | 2     3     8     |
 | 8     9     167   | 2     36    367   | 16    4     5     |
 | 2     3     16    | 5     4     8     | 9     7     16    |
 *-----------------------------------------------------------*


Multi-colouring on digit 6 makes an exclusion that turns everything else into singles.

Tracy

[re'born]

Sudophil,

Singles, locked candidates and naked triples/hidden pairs gets you to this point:

Code: Select all

 
 *-----------------------------------------------------------*
 | 4     1     9     | 3     7     5     | 8     6     2     |
 | 7     8     2     | 46    9     46    | 5     1     3     |
 | 3     6     5     | 8     2     1     | 7     9     4     |
 |-------------------+-------------------+-------------------|
 | 1     4     67    | 9     8     2     | 3     5     67    |
 | 9     57    8     | 167   356   367   | 4     2     167   |
 | 56    2     3     | 1467  56    467   | 16    8     9     |
 |-------------------+-------------------+-------------------|
 | 56    57    4     | 67    1     9     | 2     3     8     |
 | 8     9     167   | 2     36    367   | 16    4     5     |
 | 2     3     16    | 5     4     8     | 9     7     16    |
 *-----------------------------------------------------------*


Multi-colouring on digit 6 makes an exclusion that turns everything else into singles.

Tracy

Tracy,

Of course the multi-colouring is a tad bit of overkill since there is a naked pair in r6c15 that will also turn everything into singles.

[underquark]

Of course the multi-colouring is a tad bit of overkill since there is a naked pair in r6c15 that will also turn everything into singles.

Agree. Often there is no "best way" to solve every puzzle, just keep your eyes open to the many possibilities.

[sudophil]

Fill in the candidates (possibilities for each cell). You will see many pairs and triples scattered throughout this paricular puzzle.

Consider Box1:

Code: Select all

2349     1        29
7        8        269
3469     69       5

2, 6 and 9 can only exist in a certain 3 cells and can thus be excluded from other cells in that box:

Code: Select all

34       1        29
7        8        269
34       69       5

Now note that there has to be a 2 somewhere in Box1 and it has to be in the 3rd column. This excludes 2s from anywhere else further down in that column.

I had found the 34's since the 2 and 3rd cols are taken. I don't fill in all candidates just pairs and if I get stumped, then I fill in the triples. I already know about the 2's

But if the other posters say it is there are other pairs then I will have to continue on.

I'm pretty sure the next clue is not a pair so I will look harder at triples.

[sudophil]

triples it is.

I think you all should quit filling in all the candidates, just for a challenge.
Fill in only pairs and then triples as last resort.

C1 has a triple that fixes 9 in R5 which should break it for me.

I see one in R9 removing 6 in c1 and 4 also.

Thanks for letting me know it was something simple like a pair or triple that is missed. I've yet to see one in the paper labled 'hard' that couldn't be solved with pairs and rarely triples. But I haven't been playing that long so I'm sure they'll have some tougher ones. This is the first 'hard' one in several weeks that needed a triple.

[TKiel]

Of course the multi-colouring is a tad bit of overkill since there is a naked pair in r6c15 that will also turn everything into singles.

Too busy looking for something complex too see something as simple as a naked pair. Of course nothing is as simple to spot as something that's been pointed out by someone else. I guess I'd better open my eyes wider next time. Thanks.

Tracy