The New Sudoku Players' Forum

[alkon]

Hi,
I am a relative novice here, as I've only done about 10 puzzles so far from our local newspaper. I was told that this is a hard puzzle.

I have solved all but one puzzle so far (this one).
Anyway, the attached puzzle has me stumped. I was under the impression that these puzzles were all logical, and maybe I'm missing something obvious here, but I've only been able to fill in 2 squares (3 and 5 in 4th row right) in the example below.
Everything else was given to me initially.

There are multiple choices everywhere. I tried some guesses, but there is always one bad choice that I made someplace. I'm sure that there are logical steps that I could use, but I don't know them.
With so many choices here, I can be working on this for a month!
I've read the basic instructions at this web site and have used them, but they are no help here.
Is there some other tricks that I can use to eliminate any other squares?
I don't need the puzzle solved, but I need to somehow get started again.
Thanks for your help.
Al

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

[simes]

Hi Alkon,

You need some locked candidates, followed by a hidden pair, then a couple more locked candidates. After that, it's plain sailing.

Simon

[QBasicMac]

Below is more detail, if you want it.

Mac








Locked candidate 2 in box 2
Translation: Look in box 2 and see all the two's there are in one column, hence there can be no other 2's in that column in the other boxes. Erase candidates.

Locked candidate 6 in box 5
Locked candidate 8 in box 5
Locked candidate 1 in box 6

Hidden pair 19 in row 8
Translation: In row 8 all 1's and 9's are in two cells. Each has 19. So erase all other candidates in those two cells.

Locked candidate 3 in box 8
Locked candidate 8 in row 8

....

[TKiel]

Al,

With how many techniques are you familiar There are locked candidates and a hidden pair, as mentioned above, plus there's a naked triple in both column 2 & 3, an x-wing in 5's, and a swordfish in 7's (or another x-wing if you prefer).

Check out some of the sites tso listed in his reply to your other post, they contain a lot of good information. Heck, in a week you'll be answering other people's questions.

Tracy

[QBasicMac]

there's a naked triple in both column 2 & 3, an x-wing in 5's, and a swordfish in 7's (or another x-wing if you prefer).

Heh - Only if you do things the hard way. After the moves I provided, there is nothing but singles.

Mac

[Cec]

".. but I've only been able to fill in 2 squares (3 and 5 in 4th row right)..."

Hi alkon and welcome to the forum.
When sending posts it's a good idea to follow the recommended terminology as explained by clicking HERE . Note that your reference to "squares" should be referred to as "cells". As the saying goes, the chorus sounds better when we're all using the same music sheet

Cec

[TKiel]

Mac:

Heh - Only if you do things the hard way. After the moves I provided, there is nothing but singles

Filling in singles isn't my idea of a fun puzzle, unless I'm just trying to solve it as fast as I can. I was trying to point out techniques to alkon with which he may not have been familiar. But it does illustrate the fact that there are many different paths through the jungle.

Tracy

[alkon]

Sorry it took me so long to check on this, but I've been real busy the past week or so.
Thanks to all that have helped me with this problem. Obviously, I have a lot to learn on techniques, although I had figured a few of the simpler ones out myself. Heck, I have a lot to learn on the terminology!
I have printed out a number of the techniques and terms for any future entries that I may submit.
Thanks again to all.

[Cec]

Sorry it took me so long to check on this, but I've been real busy the past week or so.
"Thanks to all that have helped me with this problem. ..."

And thanks to you Alkon - it's always nice to get feedback that the help offered was appreciated.

Cec