Life In 19x19

Posted: **Mon Nov 01, 2010 3:19 am**

This is a fuseki problem from smartgo:

Click Here To Show Diagram Code: [go]$$Wcm1 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . O . . . . . . . . . . . . . | $$ | . . . X . . . . . , . . . . . X . . . | $$ | . O . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . X . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------Black to play[/go]

This is a "failure" solution, the result being presented as "good for white":

Click Here To Show Diagram Code: [go]$$Bcm1 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . 3 2 . O . . . . . . . . . . . . . | $$ | . . 4 X . . . . . , . . . . . X . . . | $$ | . O . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . . . . . . . . . . . | $$ | . . 1 . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . X . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ --------------------------------------- Good for white[/go]

I don't see why this is good for white. Am I missing an obvious continuation, or can you immediately tell that it's good for white based on some basic principles or by comparing the result with a known joseki, etc?

My confusion comes partly from the fact that black can live easily in the corner (tripod group, by giving atari from above and extending to the left). Then the cutting black stone can escape because the ladder favours black, or black can even just let white connect and build some strength for attacking the white stone on the left side.

Well, shortly it is not obvious to me why this position is advantegous for white. Could someone please explain?

Thanks in advance.

Posted: **Mon Nov 01, 2010 4:05 am**

entropi wrote:I don't see why this is good for white....

As with all problems, add "compared to what Black could have achieved" to the end

Posted: **Mon Nov 01, 2010 5:33 am**

topazg wrote:
entropi wrote:I don't see why this is good for white....

As with all problems, add "compared to what Black could have achieved" to the end

Here is the given solution:

Click Here To Show Diagram Code: [go]$$Bcm1 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . 1 . . O . . . 3 . . . . . . . . . | $$ | . . . X . . . . . , . . . . . X . . . | $$ | . O . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . . . . . . . . . . . | $$ | . . 2 . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . X . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------Black to play[/go]

Of course it looks much cleaner and better for black than the "failure" position. But I would still like to be able to assess it independently of the alternative sequences.
Because for the failure position it doesn't say "better for white", it just says "good for white".
Or maybe I take it too literally

Posted: **Mon Nov 01, 2010 6:01 am**

entropi wrote:Of course it looks much cleaner and better for black than the "failure" position. But I would still like to be able to assess it independently of the alternative sequences.
Because for the failure position it doesn't say "better for white", it just says "good for white".
Or maybe I take it too literally

Yes, I much much prefer :b1:

in the second diagram, and :b3:

both attacks and develops. White wants control in a handicap game, and here the control is all Black's.

I read "good for X" as "X is comparatively pleased, things could have gone a lot worse for him than this".

Posted: **Mon Nov 01, 2010 7:20 am**

^ what he says.

In a problem, you always want to find the best result possible. Thus, if there exists some move A that always gives you a better result for you than move B, then move B is bad, full stop.

That said, let's look at this particular case:

Click Here To Show Diagram Code: [go]$$Bcm1 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . 2 4 . . . . . . . . . . . . . . | $$ | . 0 X O 1 O 6 . . . . . . . . . . . . | $$ | . 8 O X 3 5 . . . , . . . . . X . . . | $$ | . O 7 . . . . b . . . . . . . . . . . | $$ | . 9 . X . . . . . . . . . . . . . . . | $$ | . . # . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . X . . . | $$ | . . . a . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . X . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Ordinarily, a continuation like this, followed by an invasion around 'a' or a keima at 'b' would be fairly natural. But now, :bs:

is in a super-overconcentrated location - it adds very little to the strength of black's wall. Because this stone is so inefficient, black is not happy with this result, so now he will have to look for something better!

Posted: **Tue Nov 02, 2010 5:27 am**

Thanks a lot for the answers. Indeed I should have formulated my question independently from the problem, like "is this position locally favourable for white?". My mistake...

Anyway, the variation gaius suggested looks indeed good for white because black looks overconcentrated.

But just from the feeling I would say there can be so many variations that it should be hard to call the position "good for white" based on one sequence.

I unsuccessfully tried to evaluate it using tewari (I hope to remember the name correctly) analysis or by comparing the result to a known joseki but I was just stuck with more questions than answers.
Anyway probably the situation is too open yet, at least for sdk level.

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