Advanced methods and approaches for solving Sudoku puzzles

I'm very new to this and don't really know anyone else who is familiar with Sudoku. I'm trying to learn through experience and have been solving puzzles from the following site:

www.dailysudoku.co.uk

It is claimed that all puzzles at the above site are solvable through logic alone and do not require trial and error (I won't wade into that dispute). After solving several, I got stuck on one and asked for a hint (after using the drawer tool to enter my progress). Here's where I'm at:

*** 91* ***
3** *2* *1*
175 **8 629

*52 *** 496
6** 5*9 237
*** *6* 185

5*6 8** 94*
*8* *5* **2
*** *94 ***

The hint is that Row 5, Column 3 should be a 1. I know that a 1 needs to go in either Column 2 or 3 of Row 5, but I am missing the logic that compels Column 3. I'm sure there's an obvious answer staring me in the face and that I'll feel like a fool when I find out, but I'm at a total loss right now. Any explanation would be greatly appreciated. Thank you.
jakeinprogress

Posts: 2
Joined: 21 June 2005

1. row 8 has a subset of 4 and 9 in columns 1 and 3, so other candidates for these cells can be eliminated.

Then
2. theres a "disjoint subset" with 4, 8 and 9 in cells (1,3)(2,3)(8,3). This allows you to update the candidates for (5,3) and (6,3)

Then you can place the 1 in (5,3)

(My attempt at explaining these techniques can be found from the link below by following the "techniques" link in the header.)
Last edited by simes on Sun Dec 11, 2011 9:56 am, edited 1 time in total.
simes

Posts: 324
Joined: 11 March 2005
Location: UK

Thank you. Predictably, it now seems obvious. But I read - and more importantly, processed - much of the link you sent me. Hopefully, my eyes will spot things more and more quickly with further repetition. No reason to think otherwise, I guess. Thanks again.
jakeinprogress

Posts: 2
Joined: 21 June 2005