life in corner problem

[ericf]

$$Wcm31
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . O . X . W . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . O O X . . . |
$$ | . . . . . . . . . . . . . . O O X X . |
$$ | . . . . . . . . . . . . . . . . O O . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |

Click Here To Show Diagram Code

[go]$$Wcm31
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . O . X . W . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . O O X . . . |
$$ | . . . . . . . . . . . . . . O O X X . |
$$ | . . . . . . . . . . . . . . . . O O . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |[/go]

(snippet of board shown.)

Hi, white invaded at R17 (shown) and I played R15 and got killed. Could I have survived? (I don't see anything, but that doesn't mean much. Alternatively, does S16 (or some other move) live?

thanks,
Eric

[EdLee]

Try S15 -- another first feeling.

[Dusk Eagle]

It doesn't look very good for black to be in this shape in the first place. White has got him sealed in in the corner, which is bad for black. Also, as you can see, black has a few weak spots, such as at R17 (where white played) and S16. Even at the dan level, this is a complicated position, but most dan players would not find themselves in this position to begin with, as

1) They wouldn't want to let white seal them in.

2) They'd be especially wary about being sealed in while having a weak point such as S16 lurking around for white to hit at (most of the time, I would avoid forming that shape in the corner to begin with).

As for the position itself, in some variations black gets enough outward strength to run to the left, so the placement of stones over there also becomes a factor in whether black can live. That being said, I *think* S16 lets black live without needing to rely on escaping to the left, but there's a lot of non-trivial variations.

[Uberdude]

s16 p18 q18 q17 r18 seems to live by letting white save r17 and squeezing around. (r18 at o18 loses to p16).

[ericf]

thanks for all the ideas -- in short, I should have played s16 early on to protect the group and avoided these complications.

[Bill Spight]

thanks for all the ideas -- in short, I should have played s16 early on to protect the group and avoided these complications.

My guess, as Dusk Eagle suggests, is that there probably was an even earlier error.

[ericf]

the way I play, I'm sure there were many! (but hopefully less and less as time goes on...)
I think the big problem is that I don't really understand the concept of "good shape" which I keep hearing about...but I'll work on it -- thanks for the help.

[EdLee]

I don't really understand the concept of "good shape" which I keep hearing about...

Have your serious games reviewed (here or on KGS, etc.).

[billywoods]

the big problem is that I don't really understand the concept of "good shape"

Well, in particular:

$$
$$ . . . . . . . . . .
$$ . . . . . . . . . .
$$ . . O X . T . . . .
$$ . . O X C . . . . .
$$ . . . O X X . . . .
$$ . . O . O O . . . .
$$ . . . . . . . . . .

Click Here To Show Diagram Code

[go]$$
$$ . . . . . . . . . .
$$ . . . . . . . . . .
$$ . . O X . T . . . .
$$ . . O X C . . . . .
$$ . . . O X X . . . .
$$ . . O . O O . . . .
$$ . . . . . . . . . .[/go]

This shape has a weak point at triangle. If black plays there, the shape becomes strong, encloses an eye, and can move flexibly. If white plays there, the shape becomes weak, encloses no eye, and has a cut at circle.

I read this page at some point. It amused me, and seems actually quite relevant for shape.

[Dragon Pie]

I think that what Bill Spight and Dusk Eagle were getting at is that locally black is absolutely sealed in and as a result white has outside influence facing all directions This is before we get to the weakness of the black group, white is in good shape locally.

So, for black to play like this, he must have absolutely amazing compensation whereever he tenukied that allowed him to get sealed in like this and to have such a weak group.

As for shape, that'll happen in time. You just need to do some murdering and get murdered, so that you learn which shapes are weak and which are strong. It comes with experience.

[Bill Spight]

I think that what Bill Spight and Dusk Eagle were getting at is that locally black is absolutely sealed in and as a result white has outside influence facing all directions This is before we get to the weakness of the black group, white is in good shape locally.

Well, there is that, but Black probably played poor shape moves to reach that position.