The New Sudoku Players' Forum

[Roy McCoy]

I don't see anything at this point on this one (no rating indicated):

Code: Select all

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

Can someone please tell me what I should look for here? Thanks.

[PIsaacson]

Roy,

If you're using a PM grid, look for a <459> naked triple in column 2. Applying that will reduce the puzzle to an STE (singles to/through end) condition.

If you are manually solving without pencil marks, then I have no idea how you would recognize a locked set just from the givens. You'll have to study the manual solving threads to learn what's possible.

Cheers,
Paul

[eleven]

When solving manually, its easier to spot the hidden pair 67 in r13c2.

Code: Select all

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

You can see, that both in box 1 and column 2 the cells marked X are the only possible ones for both 6 and 7.

[Roy McCoy]

Thanks, Paul & eleven. I neglected to check "Notify me when a reply is posted", so I didn't see yours till coming back after having found the naked triple via the Sudoku Solver at sudokuwiki.org, which looks like a great tutor in situations like this one - not the least because the "hint" is immediate. I'm so dumb I didn't understand or see the naked triple until I read the explanation at http://www.sudokuwiki.org/Naked_Candidates#NP.

I'm not so dumb that I can't understand or see the hidden pair 67, but where would I have gone from there?

[PIsaacson]

Roy,

If you're using SS, then reload your puzzle and turn off show candidates (ctrl W). Highlight 3s, look at column 2 and now that you "know" r13c2 is the hidden pair <67>, where else can you place a 3 except in r2c2? From there, the puzzle falls pretty easily even without showing candidates. It's fun to use the non-candidates showing mode to hone your manual skill for PM-less grid solving.

Cheers,
Paul

[Roy McCoy]

Thanks again. Neither ctrl W nor cmd W turn off Show Candidates on my Mac, and I'd think ctrl W would close your browser window in Windows. But it doesn't matter, I see the checkbox and can get the same result with a simple click. I can't, however, find a convenient Mac alternative to "Pressing 'Enter' on the keyboard after clicking on Take Step is a quick way to step through all strategies," since I don't have an Enter key (just Return) on my MacBook Pro laptop, and I'm not sure it would work if I did.

I downloaded a "Sudoku Explainer" Java program yesterday that claims to list all the applicable techniques that can be applied at any point in the solution, and I'll certainly be trying this out. I may likely wind up preferring SS's emphasis on the basic techniques, however, since I may not find it useful always to be seeing obscure methods that I wouldn't often use or need to use.

I mistyped the URL in my subject line, by the way. It should be "metronieuws" rather than "metroniews". I miss the U often on this keyboard, sorry.

[PIsaacson]

Roy,

Not that I want to "diss" SE, but if I were you, I would download Hobiwan's HoDoKu http://hodoku.sourceforge.net/en/index.php

It contains more current techniques than Sudoku Explainer, plus it can generate puzzles with various degrees of difficulty and with various mandatory techniques. If requested, it too has the ability to show you all the possible paths from any given position.

Another good one to have if you're into nrczt is SudoCue latest beta version 3.2.0 http://www.sudokuvault.com/SudoCueV320.msi

Cheers,
Paul

[Roy McCoy]

I've downloaded HoDoKu, thanks. The other link doesn't work and I could only find earlier versions at www.sudocue.net, but I don't know what nrczt is and it looks like SudoCue is Windows-only anyway. Thanks!

[Roy McCoy]

The other link (http://www.sudokuvault.com/SudoCueV320.msi) turned out to work after all, sorry. It downloaded the program directly to my disk, though it also left a cryptic browser window open that made it look like it didn't work. Can't use SudoCue on a Mac, though.

[Roy McCoy]

Not that I want to "diss" SE, but if I were you, I would download Hobiwan's HoDoKu http://hodoku.sourceforge.net/en/index.php

I can easily take your word for it that as a selfstanding program HoDoKu is preferable to Sudoku Explainer, but what about HoDoKu vs. Sudoku Solver at the sudokuwiki.org website? I can continue to try both and will, but am interested in what others think, thanks.

[Roy McCoy]

I'm still interested in HoDoKu vs. Sudoku Solver, particularly since I'm having real trouble getting the hodoku.jar file to launch on Mac OS X 10.6.7. I just now couldn't launch the copy I had, downloaded a new copy, and could open it but only once. When I closed it and tried to open it again, I got the same alert saying it couldn't be opened.

SS at sudokuwiki.org seems fine, but I'm wondering why it doesn't include Naked Pairs and Hidden Pairs in its examples popup menu. I know these are or should be easy to find, but i was still thinking of starting off with these in a series of practice exercises. Thanks.

[kifotv]

I think hodoku is a great program, and I've never had a mac but there are a couple things, You probably already searched, but you may want to try some things:

http://macosx.com/tech-support/how-to-e ... /9549.html

That thread covers pretty much the basic two, the first being to make sure that the java launcher is set as default to open .jar files. Another thing to try is launching it from the command line. He lists a few lines in a few places on his site, with a bunch of cache size options and such, but I've never had problems with just "java -jar hodoku.jar".

If worse comes to worse, you can try emailing the guy who wrote it, not sure how much he checks it, but he got back to me pretty quickly. Worth a shot...

[Roy McCoy]

The Mac "Jar Launcher" is set as the default, and hodoku won't launch for me from the command line. It is repeatedly launching, however, if I leave it on the desktop and launch it with command-o rather than a double click. This is idiosyncratic, but if I can use the program with these odd conditions I don't suppose I need to pursue the question further. Thanks!

[PIsaacson]

Roy,

I use SS, but not extensively. It has many techniques (APE and various forcing chains) that are also specific to SE, so I sometimes use it to cross-check SE solution paths. But, I prefer to have stand-alone programs that I can run without needing a connection to the Internet, so HoDoKu is one of my favorites. It contains "newer" techniques that are the basis of my manually solving efforts, and it can generate puzzles containing specific techniques for training.

I'm not a mac-head, so I can't help you there, but it seems strange since it runs fine on fedora linux... Have you "stepped up" (as they say in their ads) to the Apple Store Genius Bar???

Cheers,
Paul

[Roy McCoy]

Thanks, Paul. I'm pretty much always connected to the Internet, so SS is no disadvantage to me on that account. I've now had another look at SE, which also needs to be put on my desktop to run, it seems. I'll maybe ask the guys at an Apple store here about this sometime, but there's no rush.