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Why is this variation "good"?
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Author:  Kirby [ Mon Feb 22, 2016 6:40 pm ]
Post subject:  Why is this variation "good"?
I was going through one of my books, and came across this problem:
Click Here To Show Diagram Code
[go]$$cm1
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . W . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . X . . . |
$$ | . . X O O X . . . , . . . . . , . . . |
$$ | . O O X X . . X . O . . O . . X . . . |
$$ | . O . O X . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


The first failure diagram provided is as below:
Click Here To Show Diagram Code
[go]$$cm1
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . 5 7 . . . . . . . . . . . . . . |
$$ | . . . O 3 6 . . . . . . . . . . . . . |
$$ | . . X 1 2 4 . . . . . . . . . X . . . |
$$ | . . X O O B 8 . . , . . . . . , . . . |
$$ | . O O B B . . B . O . . O . . X . . . |
$$ | . O . O B . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


The explanation for the failure diagram basically says that, while black can capture the one white stone in a ladder, black's damage is big.

I can see that. Yeah, the marked group looks pretty sad.


One of the variations in the solution diagram is as follows:
Click Here To Show Diagram Code
[go]$$cm1
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . 1 . . . . . . . . . . . . . . . |
$$ | . 7 2 O 5 . . . . . . . . . . . . . . |
$$ | . . X 3 4 6 . . . . . . . . . X . . . |
$$ | . . X O O X . . . , . . . . . , . . . |
$$ | . O O X X . . X . O . . O . . X . . . |
$$ | . O . O X . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


Basically, it says in the description, compared to the failure diagram, this diagram is a success for black.


My question is:
So, I get it. In the "success diagram":
Click Here To Show Diagram Code
[go]$$cm1
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . X O O X . . . . . . . . . . . . . . |
$$ | . . X X O O . . . . . . . . . X . . . |
$$ | . . X O O X . . . , . . . . . , . . . |
$$ | . O O X X . . X . O . . O . . X . . . |
$$ | . O . O X . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


It's as if white played out an extra move in a non-working ladder from the "failure diagram":
Click Here To Show Diagram Code
[go]$$Wcm1
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . 2 1 O X . . . . . . . . . . . . . . |
$$ | . . X X O O . . . . . . . . . X . . . |
$$ | . . X O O X O . . , . . . . . , . . . |
$$ | . O O X X . . X . O . . O . . X . . . |
$$ | . O . O X . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


Clearly, the :w1: :b2: exchange is bad for white. The proverb, if I recall, is that each move played out in a non-working ladder costs 7 points.

But is it really a loss of 7 points here? Is the "good variation" that much better than the "bad variation"?

To me, they seem pretty much the same, especially if white plays atari following the "good variation":


Click Here To Show Diagram Code
[go]$$cm1
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . 1 9 . . . . . . . . . . . . . . |
$$ | . 7 2 O 5 8 . . . . . . . . . . . . . |
$$ | . . X 3 4 6 . . . . . . . . . X . . . |
$$ | . . X O O B 0 . . , . . . . . , . . . |
$$ | . O O B B . . B . O . . O . . X . . . |
$$ | . O . O B . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


But since the marked black stones are still in sad shape - honestly, I don't feel the "good diagram" is that much better than the "bad diagram".

Is there really that big of a difference?


The reason I ask is because I considered the "good variation" as a possibility, but rejected it for the same reasons they said the "bad variation" was bad.

Thoughts?
Author:  Bill Spight [ Mon Feb 22, 2016 8:09 pm ]
Post subject:  Re: Why is this variation "good"?
OK, so the solution is plainly better than one of the failures. What about the others?

It may be a matter of faute de mieux. :)
Author:  Kirby [ Mon Feb 22, 2016 9:29 pm ]
Post subject:  Re: Why is this variation "good"?
Bill Spight wrote:
OK, so the solution is plainly better than one of the failures. What about the others?

It may be a matter of faute de mieux. :)


Well, in this case, I didn't come up with a satisfactory solution, so I ended up looking at the answer diagrams.

I kept trying to see if some variation like the following would work, but black seems to have too many weaknesses to get a good result:

Click Here To Show Diagram Code
[go]$$cm1
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . 5 3 . 7 . . . . . . . . . . . . . |
$$ | . 6 4 O 1 . . . . . . . . . . . . . . |
$$ | . . X 2 . 8 9 . . . . . . . . X . . . |
$$ | . . X O O X a . . , . . . . . , . . . |
$$ | . O O X X b . X . O . . O . . X . . . |
$$ | . O . O X . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


After :b9:, the weaknesses at 'a' and 'b' kind of make black fall apart.

So it's hard to see something good.

But it is a pity to end in a situation like this on the bottom, as in the solution variation:

Click Here To Show Diagram Code
[go]$$cm1
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X X . . . . . . . . . . . . . . |
$$ | . X O O X O . . . . . . . . . . . . . |
$$ | . . X X O O . . . . . . . . . X . . . |
$$ | . . X O O X O . . , . . . . . , . . . |
$$ | . O O X X . . X . W . . W . . X . . . |
$$ | . O . O X . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


White's marked stones seem effective in making things difficult for black.

On the other hand, if we ignore the local area, maybe we could wait on making a result on the left. The white two-space extension isn't weak really, but we could make some sort of influence on the bottom later, maybe?


Click Here To Show Diagram Code
[go]$$cm1
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . 5 . . . . X . . . |
$$ | . . X O O X . . 7 3 4 1 . . . , . . . |
$$ | . O O X X . . X . O 6 2 O . . X . . . |
$$ | . O . O X . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


I guess even this result isn't great, since white could follow up with a hane:
Click Here To Show Diagram Code
[go]$$cm1
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . X . . 8 . . . . 5 . . . . X . . . |
$$ | . . X O O X . . 7 3 4 1 . . . , . . . |
$$ | . O O X X . . X . O 6 2 O . . X . . . |
$$ | . O . O X . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


I think I need to practice these types of problems more, because it's hard to know what is satisfactory. With life and death problems, it's much more clear: dead, alive, ko, seki, etc.
Author:  OtakuViking [ Sat Feb 27, 2016 11:41 am ]
Post subject:  Re: Why is this variation "good"?
First of all white seems to have the advantage in the local fight because he has a base on the right while blacks 2 groups don't + he's secure and solid in the corner. So it is natural that white takes some sort of advantage. I think it's a matter of playing the best move locally, not gaining an equal or advantageous result in that part of the board.

Even so, white ends in gote with 10 (so black has sente which is worth alot) and black can also kosumi his lone stone out and maybe put pressure on the 2 space extension later on, aswell as maybe make some cap/influence play by harassing the 2 space extension.

When you take these things into account I think it looks fairly decent for black, especially if as you said, the captured ladder stone is worth an extra 7 pts.

EDIT: Out of curiosity, what book was it?
Author:  Kirby [ Sat Feb 27, 2016 4:51 pm ]
Post subject:  Re: Why is this variation "good"?
Thanks, OtakuViking.

It was this book:
http://book.daum.net/detail/book.do?boo ... 1185635101

BadukTV had an "X Files" tesuji series, and this is one of the books for it. Gogameguru translated the series, I think.
Author:  Bill Spight [ Sat Feb 27, 2016 6:51 pm ]
Post subject:  Re: Why is this variation "good"?
Click Here To Show Diagram Code
[go]$$c
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . 3 . . . . . . . . . . . . . . . |
$$ | . . 4 O 1 . . . . . . . . . . . . . . |
$$ | . . X 2 . 5 . . . . . . . . . X . . . |
$$ | . . X O O X . . . , . . . . . , . . . |
$$ | . O O X X . . X . W . . W . . X . . . |
$$ | . O . O X . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


Black makes shape and thickness, but the :wc: group is well placed.
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