Jumping out from a pincer

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skydyr
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Re: Jumping out from a pincer

Post by skydyr »

As a side note, the general dictum to play away from thickness will likely apply here also. The closer white plays to that wall, the easier it is for black to cause him trouble or make those stones useless, because of that wall.
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EdLee
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Post by EdLee »

PeterPeter wrote:I think it is well balanced.
...If that particular feature of it is good for black, then it stands to reason that I don't like that particular feature.
(Starting to repeat myself...) You decide to sell someone a shirt with a red button for $10.
You both agree it's a fair trade. You think the red button is good for that person and you don't like it.
I think this is being unreasonable.
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Re:

Post by PeterPeter »

EdLee wrote:
PeterPeter wrote:I think it is well balanced.
...If that particular feature of it is good for black, then it stands to reason that I don't like that particular feature.
(Starting to repeat myself...) You decide to sell someone a shirt with a red button for $10.
You both agree it's a fair trade. You think the red button is good for that person and you don't like it.
I think this is being unreasonable.

As white:
- I like my territory
- I dislike black's wall

That is what I mean by "well balanced".

I can like something overall, without liking every part of it.

If I can then deal with the particular bit that I dislike, then I am even happier! :)
Regards,

Peter
Bill Spight
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Post by Bill Spight »

PeterPeter wrote:
EdLee wrote:Just so we're clear:

If you are playing W,
(a) You think the result is equal for B and W (locally, anyway), but you still don't like B's wall.
(b) You think the result is not equal; you think B's wall makes it a better result for B than W, and that's (partially) why you don't like the result.

Your position is (a), and not (b) ?

Yes: (a). I like my territory, but I don't like Black's wall. If I can find a way to neutralise that wall, I win :) .


Not necessarily. ;) If you can neutralize the wall without making a tradeoff, that is to your advantage.

What is true is that territory is like money in the bank, while the territorial value of a wall is potential. In general, it does not come from using the wall to make territory. Therefore, "neutralizing the wall" by preventing territory in its vicinity does not necessarily prevent the wall from paying off.

Learning to make use of walls takes time and experience. So I recommend that beginners start gaining that experience as soon as possible. :)
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Re: Jumping out from a pincer

Post by Uberdude »

I've killed that wall before. However, it takes a lot of preparation and of course won't work if you go about it directly. The following diagram shows the sort of moves white needs to get as preparation. Obviously black shouldn't pass when white plays these, either gaining something elsewhere on the board, or else answering them more locally in which case white can probably be happy to be making some gains in sente. Then 1-3 are one way of attacking black's shape.

Click Here To Show Diagram Code
[go]$$Wc
$$ -----------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , W . . O . O W . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . X . X . . |
$$ | . . . . . . . . . . . . . . 2 . . . . |
$$ | . . . . . . . . . . . . . 1 X O O . . |
$$ | . . . . . . . . . . . . . . . X O . . |
$$ | . . . , . . . . . , . . . 3 . X O . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . W . . |
$$ | . . . . . . . . . . . . . . W . . . . |
$$ | . . . X . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ -----------------------------------------[/go]


But anyway, a more useful thing to think about is what to do next after that wall joseki. First we need to understand what are black and white aiming at in the future? Learning joseki well is just as much about learning what things to do after the joseki as the joseki itself.

Click Here To Show Diagram Code
[go]$$Wc
$$ -----------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . e . . . . d . . |
$$ | . . . O . . . . . , . . . O . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . X . X . . |
$$ | . . . . . . . . . . . . . . a . . . . |
$$ | . . . . . . . . . . . . . . X O O . . |
$$ | . . . . . . . . . . . . . . . X O . . |
$$ | . . . , . . . . . , . . . . . X O . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . b . . |
$$ | . . . . . . . . . . . . . . f . . . . |
$$ | . . . X . . . . . c . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ -----------------------------------------[/go]


The above diagram labels the various interesting areas for the future. Something important to note is that they are not isolated, but can affect each other:
    a - black would like to connect here to make some thickness, keep r14 safe, and separate the white groups above and below; white would like to wedge in here to make some profit, cut off r14 and connect his groups above and below.
    b - black would like to play here (or r7) to limit white's eyespace on the side (aims at s9 placement) and develop his lower right corner; likewise white wants to increase his eyespace here, stop getting sealed in and approach black's corner
    c - black has made a wall on the right side and would like to play here to build a moyo, white would like to split the side (k3 rather than k4) to nip the moyo in the bud.
    d - black would like to live in the corner, white to get the corner
    e - black here is the classic play on 3rd line against a 4th line stone and if he has already got the connection at a then this move can attack white's corner. White can prevent this kind of move with a play at k17 or l16.
    f - if white already has b then there is a cut here white might like to make, and black might want to defend.

So putting all these aims together, what would be a sensible way for both sides to continue? Well a and b are essentially miai so white's group is perfectly safe, thus it's reasonable to split black's moyo below c.

Click Here To Show Diagram Code
[go]$$Wc
$$ -----------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . O . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . X . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . X O O . . |
$$ | . . . . . . . . . . . . . . . X O . . |
$$ | . . . , . . . . . , . . . . . X O . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . 1 . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ -----------------------------------------[/go]


White could also play on the side, but then black makes his moyo:

Click Here To Show Diagram Code
[go]$$Wc
$$ -----------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . O . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . X . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . X O O . . |
$$ | . . . . . . . . . . . . . . . X O . . |
$$ | . . . , . . . . . , . . . . . X O . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . 1 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . 2 . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ -----------------------------------------[/go]


Continuing from the first variation, black would like to pressure the white group so connects at a and white jumps to b. Something to note is that if white doesn't play b black could play there and even though white can still live, it will be a miserable small life in which you have to make bad exchanges (e.g. p for q which helps black's corner, or r for s which weakens white's corner above as black can now jump to the 3-3 point and be connected) and black getting to seal in sente is very satisfying for him.

Click Here To Show Diagram Code
[go]$$Wc
$$ -----------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . O . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . X . X s . |
$$ | . . . . . . . . . . . . . . 2 . . r . |
$$ | . . . . . . . . . . . . . . X O O . . |
$$ | . . . . . . . . . . . . . . . X O . . |
$$ | . . . , . . . . . , . . . . . X O . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . X . . p . |
$$ | . . . . . . . . . . . . . . . . 3 q . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . 1 . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ -----------------------------------------[/go]


But now that black got the connection at a in sente, the white group above is separated, so the move at e becomes powerful, and white moves out:

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


This is a natural flow of moves, with trading of miai points.

One variation I didn't show yet was white getting a, so to show that:

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


Something to note here is that black's move at e has become less interesting as, now that white has connected his groups through at 5, it is not attacking the corner, just destroying a little bit of territory. Also note that white's 5 makes it harder (but not impossible e.g. 5 as hanging connection for a ko) to invade at the 3-3 point as black can no longer get the 2nd line hane and connect in sente (the kill shown in the 2nd diagram is not totally clean, there is some bad aji outside):

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


But see how white's stone at q14 takes a liberty white means black's cut at b doesn't work as white answers at c.

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


Thinking about the future possibilities like this is what it truly means to study joseki.
Uberdude
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Re: Jumping out from a pincer

Post by Uberdude »

PeterPeter wrote:From the end of this joseki, how practical would it be for white to say, "I don't like your outward-facing wall, I am going to build my own one here to neutralise it."


Just a final point about this way of thinking. Black does not want to use his wall to make a few points in the centre, so playing a stone near it is rather pointless. Instead, black wants to use his wall to attack weak groups and make territory around the sides. So the way to neutralize the wall is to prevent black making those good moves round the sides. To illustrate here is a recent game of mine (I'm white):

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



Click Here To Show Diagram Code
[go]$$Bcm11
$$ -----------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . 0 . 6 . 4 O O . X . . . . . |
$$ | . . . X . . . . 5 1 X 2 . . . O . . . |
$$ | . . . . . . 7 . . . . 3 9 X . . . . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . 8 , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . , . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ -----------------------------------------[/go]


Click Here To Show Diagram Code
[go]$$Bcm21
$$ -----------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . O . O . O O O . X . . . . . |
$$ | . . . X . . . . X X X O . . . O . . . |
$$ | . . 3 . . . X . . . . X B X . . . . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . 2 . a . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . b . . |
$$ | . . . 5 . . . . . . . . . . . 8 . . . |
$$ | . . O 6 4 . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . 1 . 7 . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . , . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ -----------------------------------------[/go]


The move I want to to focus on is :w28:, which I think is a good move (a 5d agreed). The other thing I considered was defending my group at a, but I thought it wasn't actually so weak and that black had made a mistake by not ensuring he got sente to play at b soon after the marked connection. The move at b is a major way black can efficiently use his wall. By preventing that I neutralize his wall by building territory and making my groups strong, rather than playing dame in the centre of the board.
Bill Spight
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Re: Jumping out from a pincer

Post by Bill Spight »

Uberdude wrote:Learning joseki well is just as much about learning what things to do after the joseki as the joseki itself.


Let me second that. :)

When I started studying joseki, which was after I had been playing go for more than a year, the first book I bought was about deviations from joseki. The second one was about how to play after joseki. :)
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Re: Jumping out from a pincer

Post by skydyr »

Bill Spight wrote:
Uberdude wrote:Learning joseki well is just as much about learning what things to do after the joseki as the joseki itself.


Let me second that. :)

When I started studying joseki, which was after I had been playing go for more than a year, the first book I bought was about deviations from joseki. The second one was about how to play after joseki. :)


For me, one of the most mind opening things I had happen was that I played this simple joseki everyone learns soon as white:

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


Later in the game, black attached to :w2:, and I was flabbergasted that a group I'd thought of as strong and solid could be torn apart so easily, even though black had played moves around it. It definitely made me question what I actually knew about joseki, and started me looking into them much more deeply, both in terms of variations and in follow ups.
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Post by EdLee »

skydyr wrote:Later in the game, black attached to :w2:, and I was flabbergasted...
Yes, (painful) experience and reviews are so vital. :) There are four ways to attach to :w2: --
I assume you meant :b7: ? ...and where were the additional surrounding B stones -- at (a) and/or (b) ? :)
Click Here To Show Diagram Code
[go]$$
$$ -----------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . a 4 . . . . . . . . . . . . . . . |
$$ | . . 5 . . 2 7 . 6 . b . . . . . . . . |
$$ | . . . 1 . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . 3 . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |[/go]
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Re: Jumping out from a pincer

Post by PeterPeter »

Uberdude wrote:
Click Here To Show Diagram Code
[go]$$Bcm21
$$ -----------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . O . O . O O O . X . . . . . |
$$ | . . . X . . . . X X X O . . . O . . . |
$$ | . . 3 . . . X . . . . X B X . . . . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . 2 . a . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . b . . |
$$ | . . . 5 . . . . . . . . . . . 8 . . . |
$$ | . . O 6 4 . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . 1 . 7 . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . , . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ -----------------------------------------[/go]

The move at b is a major way black can efficiently use his wall.

Can you explain that to a beginner? How can a wall in the centre help a stone some way off to the side?

Thank you.
Regards,

Peter
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Post by EdLee »

Uberdude wrote:The move at [ :b1: ] is a major way black can efficiently use his wall.
PeterPeter wrote:Can you explain that to a beginner? How can a wall in the centre help a stone some way off to the side?
(To save space, we can ignore the rest of the board for now, or if you like, keep :white: at the lower right star point as in Uberdude's diagrams. )
Click Here To Show Diagram Code
[go]$$B Board 1
$$ --------------------------
$$. . . . . . . . . . . . . |
$$. . . . . . . . . . . . . |
$$. O . O O O . X . . . . . |
$$. . X X X O . . . O . . . |
$$X . . . . X X X . . . . . |
$$. . . . . . . . . O . . . |
$$. . . . . . . . . . . . . |
$$. . . . . . . . . . 1 . . |
$$. . . . . . . . . . . . . |
$$. . . , . . . . . , . . . |[/go]
As an extreme (and contrived) example, compare the above Board 1 with the following Board 2:
Click Here To Show Diagram Code
[go]$$B Board 2
$$ --------------------------
$$. . . . . . . . . . . . . |
$$. . . . . . . . . . . . . |
$$. O . O O O . O . . . . . |
$$. . O O O O . . . O . . . |
$$O . . . . O O O . . . . . |
$$. . . . . . . . . O . . . |
$$. . . . . . . . . . . . . |
$$. . . . . . . . . . 1 . . |
$$. . . . . . . . . . . . . |
$$. . . , . . . . . , . . . |[/go]
- How would you feel as :b1: in the two situations ?
- In Board 1, who is attacking who -- :b1: or the 2 lone :white: stones ?
- In Board 2, how is the balance of power for W and B different from Board 1 ?
Compared to Board 2, in Board 1, the presence of all the extra B stones can only help :b1:,
assuming perfect play by both B and W. (Of course, there are a million variations to consider,
including the ones where B decides to let :b1: be damaged on purpose for other gains.)
Uberdude or others may be happy to show some continuations to :b1: in Board 1, but as Bill said,
Bill Spight wrote:Learning to make use of walls takes time and experience.
So I recommend that beginners start gaining that experience as soon as possible. :)
So any explanation here is only a starting point.
To start understanding the relationship between the B stones and :b1:,
you must experience many different (and similar) situations, one by one, over time.
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Re: Jumping out from a pincer

Post by Uberdude »

PeterPeter wrote:Can you explain that to a beginner? How can a wall in the centre help a stone some way off to the side?


In essence, the strength of the black wall and the n15 connection and o17 stone separating the white corner from the top side group means that the white corner is weak and must be careful of its eyespace, so black can make benefecial exchanges to threaten this group and build elsewhere. In detail:

Say I played my other move on the left. First let's look at a bad move for black, trying to make territory next to his wall with something like :b29:. In terms of local shape, it's a nice enough move (2 space jump from 3 stone wall, though could go further with the extension of the wall to the right of the 3 stones) and if black's wall ever got weak and needed to make some eyeshape it could be ok, but now black's wall is perfectly strong and this is a passive move which makes just half a dozen points and allows white to make a lot more on the side.

Click Here To Show Diagram Code
[go]$$Bcm29
$$ -----------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . O . O . O O O . X . . . . . |
$$ | . . . X . . . . B B B O . . . O . . . |
$$ | . . X . . . X . . . . X X X . . . . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . O . O . . . . 1 . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . 2 . . . |
$$ | . . O O O . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . X . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . , . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ -----------------------------------------[/go]


So for black's good move, if white ignores black gets to seal white in the corner and now you can see his wall working well to develop a large area in the centre. White needs to spend a move in the corner now or is in real danger of dying (and even then it is a miserable small life) so then black can expand his moyo along the right side. It's not territory yet, but even if he only gets half of it that's a lot of points.

Click Here To Show Diagram Code
[go]$$Bcm29
$$ -----------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . 4 . . . |
$$ | . . . . . O . O . O O O . X . . . . . |
$$ | . . . X . . . . X X X O . . . O . . . |
$$ | . . X . . . X . . . . X X X . . . . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . O . O . . . . . . . . . 3 . . . . |
$$ | . . . . . . . . . . . . . . . . 1 . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . O O O . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . X . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . 7 . 5 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . , . . . . . O . . . |
$$ | . . . . . 2 . . . . . . . 6 . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ -----------------------------------------[/go]


To prevent getting sealed in and black having such a huge centre potential, white should come out and separate black. This move also threatens to press black down low if black tenukis. White would build his own influence now which negates black's thickness on the top side.

Click Here To Show Diagram Code
[go]$$Bcm29
$$ -----------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . O . O . O O O . X . . . . . |
$$ | . . . X . . . . X X X O . . . O . . . |
$$ | . . X . . . X . . . . X X X . . . . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . O . O . . . . . . . . . 2 . . . . |
$$ | . . . . . . . . . . . . . . . . 1 . . |
$$ | . . . X . . . . . . . . . . . 4 5 . . |
$$ | . . O O O . . . . , . . . . . 6 7 . . |
$$ | . . . . . . . . . . . . . . . 8 . . . |
$$ | . . X . X . . . . . . . . . . . 9 . . |
$$ | . . . . . . . . . . . . . . 0 . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . , . . . . . O . . . |
$$ | . . . . . 3 . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ -----------------------------------------[/go]


So black should help his side stone to stop it getting pressed down low and develop his own position on the side. In terms of territory, white's kosumi didn't make any, whilst black's knight's move on the side is likely making some points there. This is all thanks to that imposing black wall above scaring white into having to be defensive. Black is using his wall at the top to make territory on the right side.

Click Here To Show Diagram Code
[go]$$Bcm29
$$ -----------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . O . O . O O O . X . . . . . |
$$ | . . . X . . . . X X X O . . . O . . . |
$$ | . . X . . . X . . . . X X X . . . . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . O . O . . . . . . . a . 2 . . . . |
$$ | . . . . . . . . . . . . . . . . 1 . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . O O O . . . . , . . . . . 3 . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . X . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . , . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ -----------------------------------------[/go]


White now faces a choice. He could keep running into the centre but this doesn't really affect black much, doesn't make any territory or eyes. So probably it's best to make some eyes and territory in the corner to make his group safe. The following is one such sequence. White lives with around a dozen points in the corner and can also aim at later linking up at a, black can aim at b himself to prevent this in maybe sente (timing of this is hard)

Click Here To Show Diagram Code
[go]$$Wcm32
$$ -----------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . a b 5 . . . |
$$ | . . . . . O . O . O O O . X . . . . . |
$$ | . . . X . . . . X X X O . . . O . . . |
$$ | . . X . . . X . . . . X X X . . . . . |
$$ | . . . . . . . . . . . . . . . O 3 . . |
$$ | . . O . O . . . . . . . . . O . 2 . . |
$$ | . . . . . . . . . . . . . . . 1 X . . |
$$ | . . . X . . . . . . . . . . . 4 . . . |
$$ | . . O O O . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . X . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . , . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ -----------------------------------------[/go]


Black now has sente so can approach the lower right corner to develop his right side territory.

Click Here To Show Diagram Code
[go]$$Wcm32
$$ -----------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . . . . O . O . O O O . X . . . . . |
$$ | . . . X . . . . X X X O . . . O . . . |
$$ | . . X . . . X . . . . X X X . . . . . |
$$ | . . . . . . . . . . . . . . . O O . . |
$$ | . . O . O . . . . . . . . . O . X . . |
$$ | . . . . . . . . . . . . . . . O X . . |
$$ | . . . X . . . . . . . . . . . X . . . |
$$ | . . O O O . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . X . . . . . . . . . . . a . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 6 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . , . . . . . O . . . |
$$ | . . . . . b . . . . . . . 7 . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ -----------------------------------------[/go]


The right side is not totally safe yet (e.g. there is still an invasion point at a to consider) but as black I would probably play at b in the lower left now, but for the sake of argument let's say black completes his territory there:

Click Here To Show Diagram Code
[go]$$Wcm32
$$ -----------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . . . . O . O . O O O . X . . . . . |
$$ | . . . X . . . . X X X O . . . O . . . |
$$ | . . X . . . X . . . . X X X . . . . . |
$$ | . . . . . . . . . . . . . . . O O . . |
$$ | . . O . O . . . . . . . . . O . X . . |
$$ | . . . . . . . . . . . . . . . O X . . |
$$ | . . . X . . . . . . . . . . . X . . . |
$$ | . . O O O . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . X . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . 0 . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . , . . . . . O . 8 . |
$$ | . . . . . . . . . . . . . O . . 9 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ -----------------------------------------[/go]


Black's now made around 20 points on the right side. This was thanks to the power of his wall on the top letting him attack white's corner and in the process develop the side. But don't just think of this as what black's made, also think about white could have made here but didn't. If white made 20 points here then the difference is 40 points! (Of course white has also made some points in the top left and bottom left corner too). That's why using the wall to make points on the side is efficient, it's a big swing from white points to black points. If you make a few points in the centre as in the first diagram you just make a few points, it's not like white was going to make any there anyway.
skydyr
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Re:

Post by skydyr »

EdLee wrote:
skydyr wrote:Later in the game, black attached to :w2:, and I was flabbergasted...
Yes, (painful) experience and reviews are so vital. :) There are four ways to attach to :w2: --
I assume you meant :b7: ? ...and where were the additional surrounding B stones -- at (a) and/or (b) ? :)
Click Here To Show Diagram Code
[go]$$
$$ -----------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . a 4 . . . . . . . . . . . . . . . |
$$ | . . 5 . . 2 7 . 6 . b . . . . . . . . |
$$ | . . . 1 . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . 3 . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |[/go]


That's the one, including the black group around B.
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