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Studying the 3-3 invasion of the 4-4 when white extends
http://lifein19x19.com/viewtopic.php?f=15&t=16234
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Author:  BlindGroup [ Sat Nov 24, 2018 2:27 pm ]
Post subject:  Studying the 3-3 invasion of the 4-4 when white extends

I've been running into trouble with the black group in the position below. So, I spent a couple of hours playing around with Lizzie today. Below is my current understanding of the position. Would someone take a quick look to see if I've got this correct?



Attachments:
White Extension.sgf [2.49 KiB]
Downloaded 143 times

Author:  Gomoto [ Sat Nov 24, 2018 9:24 pm ]
Post subject:  Re: Studying the 3-3 invasion of the 4-4 when white extends

Interesting, I always pushed once more at A.

But after looking at your thoughts I will try this:
(I am not especially fond of the black move at B10 in your variations, I will go for F17 instead.)

Attachment:
idea.jpg
idea.jpg [ 299.88 KiB | Viewed 979 times ]

(ELFs opinion)

(But the joseki in the lower left is disappearing, only 5 games in my pro database (with your starting board position). White plays the F3 or E4 josekis nowadays. But there will plenty of opportunities to play this in amateur games.)

Author:  Gomoto [ Sat Nov 24, 2018 9:39 pm ]
Post subject:  Re: Studying the 3-3 invasion of the 4-4 when white extends

This is missing in your variations:
(starting with white B4, probably better option for white than G2)

Attachment:
idea2.jpg
idea2.jpg [ 247.74 KiB | Viewed 977 times ]

(LZ opinion)

Author:  Gomoto [ Sat Nov 24, 2018 9:53 pm ]
Post subject:  Re: Studying the 3-3 invasion of the 4-4 when white extends

And a game with this theme:


Author:  Gomoto [ Sun Nov 25, 2018 10:23 am ]
Post subject:  Re: Studying the 3-3 invasion of the 4-4 when white extends

I just tried it for the first time and it works nicely with this fuseki too:

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

Author:  Gomoto [ Sun Nov 25, 2018 10:24 am ]
Post subject:  Re: Studying the 3-3 invasion of the 4-4 when white extends

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


5 is a big mistake (black can tenuki) and should be at a, b or c.

Author:  BlindGroup [ Sun Nov 25, 2018 4:44 pm ]
Post subject:  Re: Studying the 3-3 invasion of the 4-4 when white extends

Thanks for the extended analysis!

Gomoto wrote:
Interesting, I always pushed once more at A.


From what I've seen with Lizzie, pushing again at A is almost always the right way to go. She is very torn between pushing at A and approaching at F17 like you suggest in this configuration as well as in the one with white in the 3-4 in the upper left (D17). Even after 8k playouts she is bouncing between the two. However, in both situations, immediately after white responds to the approach, she immediately goes back to push again at A. The reason seems to be that she sees that push as sente. She thinks that white's win percentage drops by about 7-8% if white doesn't play it. Interestingly, it has nothing to do with the black stone at Q4. She still thinks black's push is sente even if white were to briefly lose his sanity and block at D3 rather than C4 to build the wall facing the black stone.

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


Gomoto wrote:
(I am not especially fond of the black move at B10 in your variations, I will go for F17 instead.)


I agree completely! I didn't mean to suggest that move. I just picked something to allow me to isolate the changes that occurred with the push. F17 is Lizzie's preference and honestly, it makes a lost more sense.

Gomoto wrote:
(But the joseki in the lower left is disappearing, only 5 games in my pro database (with your starting board position). White plays the F3 or E4 josekis nowadays. But there will plenty of opportunities to play this in amateur games.)


Yep! But like you I see it quite often in my games.

Gomoto wrote:
This is missing in your variations:
(starting with white B4, probably better option for white than G2)


I should have been clearer about my motivation for looking at this in the first place. I agree that B4 is often bigger -- and is sente for both. I just find that in my games, my opponent usually plays the descent at G2 before B4 -- often later in the game when G2 makes more sense. In the starting board position that I present in the OP, even if white descends immediately (clearly making the move WAY too early), Lizzie will defend the corner group with only a two stone extension, but with three stones, she ignores white's move and tenukis. For some reason, I thought this meant that black was unconditionally alive even after the descent as long as he had pushed that third time. However, my opponents disabused me of this notion, and so, I did this analysis to understand why Lizzie defended with two pushes and ignored with three.

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