Sorry if the name's not very clear. This is what I mean:

Click Here To Show Diagram Code

[go]$$W Initial position
$$ ----------------------
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . 3 2 . . . .
$$ | . . . 1 . 4 . . . .
$$ | . . . . . . . . . .
$$ | . . 5 . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .[/go]

After that, at sometime white will 3-3. I see the 3 common answers from black are A, B and C:

Click Here To Show Diagram Code

[go]$$W Where to play?
$$ ----------------------
$$ | . . . . . . . . . .
$$ | . . . . c . . . . .
$$ | . . 1 a X O . . . .
$$ | . . . X b O . . . .
$$ | . . . . . . . . . .
$$ | . . B d . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .[/go]

I get the idea of black C, but I really can't understand the merit of black A and B. I guess they depend on the right white group and the position of the marked black stone. From what I recall C is usually not played when the marked black stone is at D.

Can anyone enlighten me on this matter, or show me a good reading source about this?

_________________
The similarity between Go and computing is the seemingly infinite number of possibilities.

You can look up these variations on josekipedia. (Although they don't include your "b"; instead they have a variation for C16). Long story short, E18 (your "c") allows W to take the corner while the other two options (C16 and D17) have some chance of keeping the corner.

Here's a Sensei's Library page with a few variations: http://senseis.xmp.net/?44PointLowAppro ... sion#diag2

Thank you very much!
That's exactly what I was hoping for ^^

I saw my B several times before, in most cases b get quite nice influence. Can't really find any example though ~.~

_________________
The similarity between Go and computing is the seemingly infinite number of possibilities.