Life In 19x19

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[go]$$Wc
$$ +-------------------+
$$ | . . . . . . . . . |
$$ | . . . . . O X . . |
$$ | . . O . O . X . . |
$$ | . . . . . . . . . |
$$ | . . O . X . X . . |
$$ | . O . . . . . . . |
$$ | . . X b X . X . . |
$$ | . O X a . . . . . |
$$ | . O O Y . . . . . |
$$ +-------------------+[/go]

I want to protect the marked Black stone. The computer is suggesting A, but I feel that B is better as it is closer to the important centre. Any thoughts?

Your thinking is not bad, but the answer is b3

B3 is best. If you need to connect, connecting by capturing enemy stones is always preferable to playing inside your territory.

As for d2 versus d3... this is a matter of taste and circumstance. The question comes up a lot. D3 is a "hanging connection". It normally stretches out further to affect points further away, but it leaves ko threats (the atari at e1), peeps (at e2), and various other weaknesses that the the "direct" or "solid" connection at d2 doesn't have.

b) helps more in the center but also leaves a ko threat at the bottom.

If a) or b) would make no difference in territory, a) would be clearly better.

I did look briefly at b3, and rejected it due to White connecting on a3, but I have now seen that Black can play a2 and win the corner through a snapback!

Horibe wrote:Your thinking is not bad, but the answer is b3

Is that one of those "basics"?

PeterPeter wrote:I did look briefly at b3, and rejected it due to White connecting on a3, but I have now seen that Black can play a2 and win the corner through a snapback!

Yes, but knowing the answer, it might be fun for you to read through it to make sure. It's a good readin exercise.

Bill Spight wrote:

Horibe wrote:Your thinking is not bad, but the answer is b3

Is that one of those "basics"?

Since this was also what I thought, it must be totally basic fundamentally, essentially basic.

Another connection problem. B is a mess - four cutting points, no less. What's the best way for B to connect?

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[go]$$B Corner
$$ ------------------
$$ | . . X . O . . . .
$$ | . O O X O X C . .
$$ | . O X O O O X . .
$$ | . . X X O X C . .
$$ | . . . C X C . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .[/go]

This protects 2 of the cutting points with one stone:

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[go]$$B Corner
$$ ------------------
$$ | . . X . O . . . .
$$ | . O O X O X C . .
$$ | . O X O O O X . .
$$ | . . X X O X C . .
$$ | . . . C X C B . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .[/go]

Or you could occupy one and protect the other using a ladder:

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[go]$$B Corner
$$ ------------------
$$ | . . X . O . . . .
$$ | . O O X O X C . .
$$ | . O X O O O X . .
$$ | . . X X O X B . .
$$ | . . . C X C . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .[/go]

There are a few places to set up a similar ladder, you would choose one based on the rest of the board?

Peter,

1. Oh yes, you can win the white group

2. Not as good as winning the group, but the ladders at A and B look OK, as far as we can see of the board?

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[go]$$B
$$ ------------------
$$ | . . X . O . . . .
$$ | . O O X O X . . .
$$ | . O X O O O X . .
$$ | . . X X O X . . .
$$ | . . . a X b . . .
$$ | . . . . B . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .[/go]

PeterPeter wrote:2. Not as good as winning the group, but the ladders at A and B look OK, as far as we can see of the board?

$$W
$$ ------------------
$$ | . . X . O . . . .
$$ | . O O X O Y 1 . .
$$ | . O X O O O X . .
$$ | . . X X O X . . .
$$ | . . . a X b . . .
$$ | . . c . B . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .

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[go]$$W
$$ ------------------
$$ | . . X . O . . . .
$$ | . O O X O Y 1 . .
$$ | . O X O O O X . .
$$ | . . X X O X . . .
$$ | . . . a X b . . .
$$ | . . c . B . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .[/go]

W can kill with IN SENTE, and B still has to deal with all his weaknesses.
(For example, if the situation changes later, a local vital point for W to annoy B is (c).)

PeterPeter wrote:Not as good as winning the group, but the ladders at A and B look OK, as far as we can see of the board?

No, those ladders/nets/whatever look painful. I'd rather capture!

Have you seen a ladder breaker played? In most problems we don't show the other corners, but we know that ladders are really painful so a solution with a ladder is worse than a solution without a ladder. (Likewise, we don't show ko threats in most games, but if you've fought through a lot of kos you know that an unconditional solution is always much better than a ko, and making a ko is better than a kick in the face.)

jts wrote:making a ko is better than a kick in the face.

hahaha... someone needs to take this as their sig.