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Why is LZ’s invasion better here?
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Author:  Kirby [ Mon Sep 09, 2019 1:17 pm ]
Post subject:  Why is LZ’s invasion better here?
In a recent game I played, LZ preferred invading here:

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


Compared to my normal thought of invading around the 4-4:
Click Here To Show Diagram Code
[go]$$B
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . X . . . . X . . . . |
$$ | . . . , . . . . . , . . . . . X . . . |
$$ | . . . O . . . . . . . . . . . . . W . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . X X . . . . . |
$$ | . . . O . . . . . , . O O X X X X . . |
$$ | . . . . . . . . . . . . . O X O O . . |
$$ | . . . . . . . . . . . . O . O . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


I came to wonder if there are any general principles here. My instinct is to invade close to the corner, as i did in the game, when black has played a second move in the corner as an enclosure to the 4-4. My reasoning is that it prevents black from fully enclosing the 4-4 with 3 moves.

Under what circumstances is a move like the one LZ suggested better?
Author:  Uberdude [ Mon Sep 09, 2019 1:45 pm ]
Post subject:  Re: Why is LZ’s invasion better here?
My first thought is that black has invested a lot of stones building that lower right wall (it's an old joseki if it ever was, it's good for white), so is kinda compelled to defend the points there and thus the downside of LZ's invasion, that it allows black to complete the corner, is not such a downside as it allowing white to trash the side:

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


Also, what were LZ's recommended continuations for each of the moves? Exploring those will help explain the preference. Also I suspect your corner approach could be good if black submissively defends the corner as you hope, but that's quite possibly slack and LZ's judgement of the submarine is based on black playing the best moves, not weak moves like you get away with bullying your low dan opponents :) .

P.S Black's kosumi seems to be the wrong side.
Author:  Bill Spight [ Mon Sep 09, 2019 1:50 pm ]
Post subject:  Re: Why is LZ’s invasion better here?
My 2¢:

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


With :bc: in place I don't like :w3:. Therefore I don't like :w1:.
Author:  Shaddy [ Mon Sep 09, 2019 9:35 pm ]
Post subject:  Re: Why is LZ’s invasion better here?
Kirby wrote:
In a recent game I played, LZ preferred invading here:

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


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


I don't think Black can play 1, because White's invasion at 2 is too severe. So if Black has to respond on the bottom side to the invasion, White can easily live large along the side.
Author:  Uberdude [ Mon Sep 09, 2019 10:50 pm ]
Post subject:  Re: Why is LZ’s invasion better here?
Shaddy, I did think about that 2 but White would like to play hanging connection after intercept but lacks ko threats. It is a good move to have on the radar though.
Author:  Shaddy [ Mon Sep 09, 2019 11:10 pm ]
Post subject:  Re: Why is LZ’s invasion better here?
While that would be nice, I think that even solid connection is good enough. If the bottom black piece becomes a weak group, I feel very comfortable as White.
Author:  Bill Spight [ Tue Sep 10, 2019 12:13 am ]
Post subject:  Re: Why is LZ’s invasion better here?
I have been wondering about this play.

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


If Black's best reply is :b2:, then :w1: will support :w3:. :)
Author:  Uberdude [ Tue Sep 10, 2019 1:34 am ]
Post subject:  Re: Why is LZ’s invasion better here?
If black is going to respond to LZ's invasion below such that White gets sente to play first towards the corner (e.g iron pillar, or kick, extend, keima/jump), then I am concerned that Kirby's 2-5 or bill's kosumi approach are aji keshi as they make less eyespace for White and let black keep more of the corner than the 2-4 approach.
Author:  Bill Spight [ Tue Sep 10, 2019 8:13 am ]
Post subject:  Re: Why is LZ’s invasion better here?
Uberdude wrote:
If black is going to respond to LZ's invasion below such that White gets sente to play first towards the corner (e.g iron pillar, or kick, extend, keima/jump), then I am concerned that Kirby's 2-5 or bill's kosumi approach are aji keshi as they make less eyespace for White and let black keep more of the corner than the 2-4 approach.


I think it would be interesting to make each play and see LZ's reply, with the winrate estimate of the reply and number of playouts. Then we can compare plays directly. :)

BTW, my guess is that you are suggesting a possible 2-4 as a followup if White invades at the 3-8. Yes?
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