OT : Help with sudoku

Right, this is about as OT as OT gets.

For those of you who don't know Sudoku is a mental puzzle that works in the
following way ...

You have a 9x9 grid which is sub-divided into 9 3x3 grids. The whole grid
must be filled with the digits 1-9 in each square, with the proviso that
each number must be used one and only once per row, per column and per 3x3
box.

So, for example, the puzzle might start out as ...

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

Where "b" are the blank squares which must be filled and this resolves (with
a bit of working out) to ...

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

The problem, and my question, is that I have one I'm stuck with. I can get
to the answer, but I can't work out a way of getting from where I am to the
answer without using trial and error, which I'm loathe to do.

So, I've got ...

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

Where numbers in the form x\y\z are squares where I've narrowed down the
possible values to one of those listed.

I appreciate this is a sod to read, so I've uploaded it as a graphic ...

http://www.imagehosting.us/imagehosting/showimg.jpg/?id=296523

I'm not interested in knowing what the answer is, I'm interested in knowing
the next logical step to solving this problem.

I'm sure one of the ukrm big-brains can answer this for me ... Simian?
Ivan? Sir.Tony?

--
AndrewR, D.Bot (Celeritas)
Kawasaki ZX-6R J1, Fiat Coupe 20v Turbo
BOTAFOT#2,ITJWTFO#6,UKRMRM#1/13a,MCT#1,DFV#2,SKoGA#0 (and KotL)
BotToS#5,SBS#25,IbW#34, DS#5, COSOC# Suspended, KotTFSTR#
The speccy Geordie twat.

 

Watch it! That was pretty close to a commercial post.

--
AndrewR, D.Bot (Celeritas)
Kawasaki ZX-6R J1, Fiat Coupe 20v Turbo
BOTAFOT#2,ITJWTFO#6,UKRMRM#1/13a,MCT#1,DFV#2,SKoGA#0 (and KotL)
BotToS#5,SBS#25,IbW#34, DS#5, COSOC# Suspended, KotTFSTR#
The speccy Geordie twat.

 

These have varying levels of difficulty - some of which can only be solved
by trying a path. I've looked and can't see any next logical steps which you
can follow (I've not checked you've got this far without making a mistake).

 

What was this puzzle's starting point?

You caught my attention, so I'd like a go.

 

I've put the puzzle through my solver and it tells me that it can't be
solved without guesses.

Only when row3, col3 (from top left) is confirmed as an 8 does it then
decide it is solveable, but rates it as very hard.

 

It even says "exceptionally difficult and arguably unfair" - which is
amusing. Where did you find this puzzle?

 

You need a Prolog programmer. And no, I'm not going to write it for you
cos I'm pissed.

 

{ off-topic post forwarded to }

 

In today's Torygraph, rated as "diabolical"

--
AndrewR, D.Bot (Celeritas)
Kawasaki ZX-6R J1, Fiat Coupe 20v Turbo
BOTAFOT#2,ITJWTFO#6,UKRMRM#1/13a,MCT#1,DFV#2,SKoGA#0 (and KotL)
BotToS#5,SBS#25,IbW#34, DS#5, COSOC# Suspended, KotTFSTR#
The speccy Geordie twat.

 

It was in today's Torygraph, as I said, and I don't believe there is a
logical next step. I have an Excel macro that I wrote to solve these
things, but it can't get any further than I posted.

The starting point is ...

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


--
AndrewR, D.Bot (Celeritas)
Kawasaki ZX-6R J1, Fiat Coupe 20v Turbo
BOTAFOT#2,ITJWTFO#6,UKRMRM#1/13a,MCT#1,DFV#2,SKoGA#0 (and KotL)
BotToS#5,SBS#25,IbW#34, DS#5, COSOC# Suspended, KotTFSTR#
The speccy Geordie twat.

 

I was doing so well until I found a pair of fives
in the penultimate column. :-(

 

Eh? It started in the Times a few months ago, and is indeed gloriously
addictive. So it's spreading, is it? Time to stop, then. Can't bear to be
part of anything popular ...

 

Don't be daft; he's married.