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Is it possible to eliminate this invasion?
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Author:  pocketMAD [ Thu Aug 25, 2016 3:38 pm ]
Post subject:  Is it possible to eliminate this invasion?

Image
Apologies if I've posted in the wrong forum. White invaded during sente with this C6 move. I feel I should've handled this stone when I had sente. Is it possible to destroy these stones? In the game, I failed to kill them.

Author:  Kirby [ Thu Aug 25, 2016 4:14 pm ]
Post subject:  Re: Is it possible to eliminate this invasion?

Looks a bit difficult, but I'd start with D8.

Author:  skydyr [ Thu Aug 25, 2016 7:40 pm ]
Post subject:  Re: Is it possible to eliminate this invasion?

Had black played at C6 a few moves before, instead of white, black would definitely have been strong enough to kill. I suspect (though I can't say for sure without looking at the record) that there were a few smaller moves played before white tried this. Even as it is, it's not clear that black needs to kill white to win. If black can limit white to a small group, white's other group is also pretty small and he may have enough to win that way.

Author:  trout [ Thu Aug 25, 2016 8:12 pm ]
Post subject:  Re: Is it possible to eliminate this invasion?

How would you respond to B d8?

Author:  EdLee [ Thu Aug 25, 2016 8:41 pm ]
Post subject: 

Hi pocketmad,
After Kirby's D8, then B B5 -- seems dead shape.
Click Here To Show Diagram Code
[go]$$B
$$ ---------------------
$$ | . . . . . . . X . |
$$ | . . 2 1 . . . . X |
$$ | . . O . . . X X O |
$$ | . 4 O X . . X O O |
$$ | . 3 . . X X O O . |
$$ | . . . . X O O . . |
$$ | . . X X . X O . . |
$$ | . . . X . X O O . |
$$ | . . . . X X X O . |
$$ --------------------[/go]

Author:  DrStraw [ Fri Aug 26, 2016 3:36 am ]
Post subject:  Re: Is it possible to eliminate this invasion?

In a situation like this it is useful to know a few basic proverbs. The one I am thinking about here is "The L-group is dead". EdLee applied this to show you the solution but if you had known it yourself then the moves would immediately jump out at you. This proverb is one of the most useful there is when it comes to corner invasions.

Author:  EdLee [ Fri Aug 26, 2016 4:05 am ]
Post subject: 

Hi pocketmad,
Re: DrStraw: L-group is dead

Basic dead shape:
Click Here To Show Diagram Code
[go]$$B
$$ -----------------
$$ | . . . . . . . .
$$ | . . O . X . X .
$$ | . . O . X . . .
$$ | . O O . X . . .
$$ | . . . . X . . .
$$ | . X X X . . . .
$$ | . . . . . . . .
$$ | . X . . . . . .
$$ | . . . . . . . .[/go]

Author:  Pio2001 [ Fri Aug 26, 2016 4:30 am ]
Post subject:  Re: Is it possible to eliminate this invasion?

trout wrote:
How would you respond to B d8?


What about White B4 ?

Author:  Uberdude [ Fri Aug 26, 2016 7:06 am ]
Post subject:  Re: Is it possible to eliminate this invasion?

I'm wondering what the black move was before white's last one at c6. Although killing now is still plausible, if black plays the previous move better then killing should be super easy.

Author:  xed_over [ Fri Aug 26, 2016 10:20 am ]
Post subject:  Re: Is it possible to eliminate this invasion?

DrStraw wrote:
In a situation like this it is useful to know a few basic proverbs. The one I am thinking about here is "The L-group is dead".

but its only dead if your opponent knows how to kill it :)

plus, even though its dead, it can be a source of many, many ko threats -- so depending on the ko battle, it might live in trade.

Author:  Kirby [ Fri Aug 26, 2016 10:43 am ]
Post subject:  Re: Is it possible to eliminate this invasion?

Opponent should be able to kill it if he knows the proverb ;-)

Author:  Kirby [ Fri Aug 26, 2016 10:45 am ]
Post subject:  Re: Is it possible to eliminate this invasion?

But you are right: depending on situation, making L-group can be useful. In addition to ko threats, capturing races come to mind. Though "dead", the L group has many liberties.

Author:  EdLee [ Fri Aug 26, 2016 10:45 am ]
Post subject: 

Hi Pio2001,
Quote:
What about White B4 ?
Click Here To Show Diagram Code
[go]$$W
$$ ---------------------
$$ | . . . . . . . X . |
$$ | . . . B . . . . X |
$$ | . . O . . . X X O |
$$ | . . O X . . X O O |
$$ | . . . . X X O O . |
$$ | . 1 . . X O O . . |
$$ | . . X X . X O . . |
$$ | . . . X . X O O . |
$$ | . . . . X X X O . |
$$ ---------------------[/go]
Click Here To Show Diagram Code
[go]$$W
$$ ---------------------
$$ | . . 0 . . . . X . |
$$ | . 4 9 B . . . . X |
$$ | . 5 O . . . X X O |
$$ | 7 . O X . . X O O |
$$ | . 3 2 . X X O O . |
$$ | 8 1 . . X O O . . |
$$ | . 6 X X . X O . . |
$$ | . . . X . X O O . |
$$ | . . . . X X X O . |
$$ ---------------------[/go]
Can B do better than ko ?
Click Here To Show Diagram Code
[go]$$Wm11
$$ ---------------------
$$ | 2 1 X . . . . X . |
$$ | 3 X O X . . . . X |
$$ | . O O . . . X X O |
$$ | O . O X . . X O O |
$$ | . O X . X X O O . |
$$ | X O . . X O O . . |
$$ | . X X X . X O . . |
$$ | . . . X . X O O . |
$$ | . . . . X X X O . |
$$ ---------------------[/go]
Click Here To Show Diagram Code
[go]$$W (a), (b) miai life
$$ ---------------------
$$ | . 6 . . . . . X . |
$$ | 7 5 4 B . . . . X |
$$ | . a O . . . X X O |
$$ | 9 . O X . . X O O |
$$ | . 3 2 . X X O O . |
$$ | b 1 . . X O O . . |
$$ | . 8 X X . X O . . |
$$ | . . . X . X O O . |
$$ | . . . . X X X O . |
$$ ---------------------[/go]
Click Here To Show Diagram Code
[go]$$W
$$ ---------------------
$$ | . 4 6 . . . . X . |
$$ | . 7 5 B . . . . X |
$$ | . . O . . . X X O |
$$ | . . O X . . X O O |
$$ | . 3 . . X X O O . |
$$ | 8 1 . . X O O . . |
$$ | . 2 X X . X O . . |
$$ | . . . X . X O O . |
$$ | . . . . X X X O . |
$$ ---------------------[/go]

Author:  Kirby [ Fri Aug 26, 2016 11:25 am ]
Post subject:  Re: Is it possible to eliminate this invasion?

Ed, per one of your diagrams:

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

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

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