Life In 19x19

Thanks to everybody, especially for the tip of "the art of connecting stones". I will try to find it.

But I am a little bit puzzled by the keima discussion. Pushing through the keima may be against the proverb and may in most cases end up in complex situation but it in fact is a way of cutting the keima, isn't it? And in some cases even the only way. That's what I understood from gaius' post. He doesn't say it's the best way but it is obviously one of the ways of cutting. Or am I missing an important point here?

The point is that after your cut, you want this shape:

Click Here To Show Diagram Code

[go]$$ Diagram 1: Good shape
$$ . . . . . . .
$$ . . . . . . .
$$ . . . B O . .
$$ . . O O B . .
$$ . . . . B . .
$$ . . . . . . .[/go]

instead of this:

Click Here To Show Diagram Code

[go]$$ Diagram 2: Bad shape
$$ . . . . . . .
$$ . . . . . . .
$$ . . B O O . .
$$ . . O B . . .
$$ . . . . B . .
$$ . . . . . . .[/go]

So, the good cuts are this:

Click Here To Show Diagram Code

[go]$$B Diagram 3: Strike at the waist
$$ . . . . . . .
$$ . . . . . . .
$$ . . . 1 O . .
$$ . . O 2 3 . .
$$ . . . . X . .
$$ . . . . . . .[/go]

and this:

Click Here To Show Diagram Code

[go]$$B Diagram 4: Push and cut
$$ . . . . . . .
$$ . . . . . . .
$$ . . 3 2 O . .
$$ . . O 1 . . .
$$ . . . X . . .
$$ . . . . . . .[/go]

Note the different positions of the initial black stone.

Now, in Diagram 4, you do not need much convincing that the alternative cut is inferior:

Click Here To Show Diagram Code

[go]$$B Diagram 5: Horrible shape
$$ . . . . . . .
$$ . . . . . . .
$$ . . . 1 O . .
$$ . . O 2 3 . .
$$ . . . X . . .
$$ . . . . . . .[/go]

However, in Diagram 3, weaker players might think that the alternative cut, resulting in Diagram 2, might be good. That is where a proverb is warranted.

Harleqin, that was exactly what I was (overly simplistically) trying to say. Nice explanation

Thanks for the explanation Harleqin.

But to be honest, this is one of the proverbs I have never fully understood and still do not understand the need for such a proverb (even after your nice explanation). For two reasons:

1) How is "waist" defined? Keima has two points that could be identified as "waist" and it is anyway more than obvious that you cannot cut anywhere else other than those two points. Which one is waist?

2) Why would anyone, even a weak player, try to cut like in Diagram 5? It is very much intuitive to push and cut if you have a black stone there at the initial position.

Maybe the proverb should be something like "don't cut keima with a kosumi, but strike at the other waist".
Anyway, I accept, this is just a proverb and one should not expect too much from it