Hi,

I must say that I'm still really confused to decide when it is good to attach, and when it's better not to touch the ennemy stone.
I have read that the general advice seems to be "not to attach" and use more a capping play or a keima, but in the same time, I saw so many examples where the good move is... an attaching play...
I'm really confused... Are there some general guidance to this subject ?

Any help welcome...

_________________
Converting the book Shape UP! by Charles Matthews/Seong-June Kim
to the gobook format. last updated april 2015 - Index of shapes, p.211 / 216

Well, that's such a vague question with so many "it depends", but if you want some simple advice it would be that attaching makes both players get stronger. So if you are strong and your opponent is weak and you want to attack attaching is probably not a good idea as it gets you into a 3 versus 3 liberty fight with your opponent to play first, so he will get stronger and has the local upper hand. Whereas if you are weak and your opponent is strong then attaching is more likely to make sense because you want to get strong and don't mind making an already strong opponent's formation get stronger. This is why in that thread recently when you asked Bill about "should I attach here to attack" I highlighted attach and attack as not usually going together.

Of course nearby stones make a huge difference, for example here

Click Here To Show Diagram Code

[go]$$B
$$ +------------------
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . 2 b 3 .
$$ | . . . 1 . 5 a . .
$$ | . . . . . . . . .
$$ | . . 4 . . . . . .
$$ | . . . . . . . . .[/go]

5 attaches to a weak stone so you might think that doesn't make sense, but the nearby 1 and 3 mean white can't do much with it, for example if hane at a then black cuts at b and 3 is very useful to make that cutting stone strong (this is still a joseki though, white can then jump into the corner). It's better to think of this attach of 5 as a connection making shape with 1 and 3, quite different to a random attach to a lone stone like this:

Click Here To Show Diagram Code

[go]$$W
$$ . . . . . . |
$$ . . , . . . |
$$ . . . . . . |
$$ . . . X . . |
$$ . . . 1 . . |
$$ . . . . . . |
$$ . . . . . . |[/go]

Hi oca, no.

Anyone can give you the general cookie cutter guideline, "don't attach when you're strong; attach when you're weak". But the problem is there are so many exceptions, they are practically infinite. We must look at the specific situation. Eventually, you still have to experience hundreds, and thousands and thousands of different boards, to learn what to do for each individual case.

One of those exceptions is when he is desperately short on liberties. Then contact moves increase his short term peril at the expense of their own long term weakness. But if he dies soon, that weakness does not matter.

An example of that is the classic capturing play in a position known as the crane's nest.

Click Here To Show Diagram Code

[go]$$B Killing play
$$ +------------------
$$ | . . . . . . . . .
$$ | . . X X X X X . .
$$ | . . X O O O X . .
$$ | . . X . 1 . X . .
$$ | . . . . O . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .[/go]

Compare that to a simliar position in which W is not badly short of liberties:

Click Here To Show Diagram Code

[go]$$B Bad play
$$ +------------------
$$ | . . . . . . . . .
$$ | . . X X X X X . .
$$ | . . . O O O . . .
$$ | . . . . 1 . . . .
$$ | . . . . O . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .[/go]

_________________
Help make L19 more organized. Make an index: https://lifein19x19.com/viewtopic.php?f=14&t=5207

Yes, there is some general advice.

As already indicated, attachment tends to make both players stronger. Therefore, when attacking, attachment is seldom right.
When trying to make sabaki, attachment is often the thing to do.

Also, in the Segoe-Go Seigen Tesuji Dictionary around 40% of the problems feature an attachment of one kind or other. And there are other tesuji, such as the one Joaz shows, which could be called attachments, but are not.

Also see http://senseis.xmp.net/?BillSpight%2FTouch

_________________
The Adkins Principle:
At some point, doesn't thinking have to go on?
— Winona Adkins

Visualize whirled peas.

Everything with love. Stay safe.

Um, one thing I heard was you should attach near your opponents thickness. Because when your opponent gains strength near their own thickness it's overconcentration.

I emphasize the word heard because I have never used this method. Like, I haven't even gotten to the point where I use it incorrectly.

Another thing to think about is

These are a couple of things that result from attaching:

one is creating cut points.
another is creating strength

Cut points are good for aji
strength can be misplaced.

These are some sdk ramblings of a topic a bit over my head.
If you do any studying on the subject I would love to read what you learn.

oca, see viewtopic.php?p=180744#p180744 for some attach or not examples in a game.