Life In 19x19

Posted: **Fri May 11, 2012 5:07 am**

Here's a problem from my lunch-time game on KGS. White has just played :w1:

, how should black kill? (Is it even possible to kill?)

Click Here To Show Diagram Code: [go]$$Wc Black to Respond $$ | O X X X O . X . O O O X . X X X O . . | $$ | X . X . X X X O O X X X O O X O . . . | $$ | . . . X . . . X O O . X X O O . O . . | $$ | . . . . . . . . X X . X O O O O . . . | $$ | . . . X . . . X . , X . X X O X O O . | $$ | . . . X . . . . X X O O X X X X X O . | $$ | . . . . . . . X O O . . O 1 . . . X O | $$ | . . . . . . . . . . . . . . . . . X . | $$ +---------------------------------------+[/go]

In the game, I managed to kill white's invasion. When I went over the game, afterwards, I realised that I should have stopped it entirely, several moves earlier. I also realised that white could have lived and possibly cut off my lower-right group. In fact, I couldn't find a move for black that would prevent white from doing so.

Posted: **Fri May 11, 2012 6:32 am**

EDIT: Also, have a look at this tsumego: http://eidogo.com/?game=1Lc8jeHa#1Lc8jeHa. The situation is similar, but black can live.

Posted: **Sun May 13, 2012 3:41 pm**

mw42 wrote:
$$Wc
$$ | O X X X O . X . O O O X . X X X O . . |
$$ | X . X . X X X O O X X X O O X O . . . |
$$ | . . . X . . . X O O . X X O O . O . . |
$$ | . . . . . . . . X X . X O O O O . . . |
$$ | . . . X . . . X . , X . X X O X O O . |
$$ | . . . X . . . . X X O O X X X X X O . |
$$ | . . . . . . . X O O 7 4 O 1 2 . . X O |
$$ | . . . . . . . . 8 . 3 5 . 6 . . . X . |
$$ +---------------------------------------+

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

EDIT: Also, have a look at this tsumego: http://eidogo.com/?game=1Lc8jeHa#1Lc8jeHa. The situation is similar, but black can live.

What if white plays 3 at 6?

Posted: **Sun May 13, 2012 4:55 pm**

Lamp wrote:
mw42 wrote:
$$Wc
$$ | O X X X O . X . O O O X . X X X O . . |
$$ | X . X . X X X O O X X X O O X O . . . |
$$ | . . . X . . . X O O . X X O O . O . . |
$$ | . . . . . . . . X X . X O O O O . . . |
$$ | . . . X . . . X . , X . X X O X O O . |
$$ | . . . X . . . . X X O O X X X X X O . |
$$ | . . . . . . . X O O 7 4 O 1 2 . . X O |
$$ | . . . . . . . . 8 . 3 5 . 6 . . . X . |
$$ +---------------------------------------+

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

EDIT: Also, have a look at this tsumego: http://eidogo.com/?game=1Lc8jeHa#1Lc8jeHa. The situation is similar, but black can live.

What if white plays 3 at 6?

4 at 5 works, right?

Posted: **Sun May 13, 2012 5:29 pm**

jts wrote:
Lamp wrote:
mw42 wrote:
$$Wc
$$ | O X X X O . X . O O O X . X X X O . . |
$$ | X . X . X X X O O X X X O O X O . . . |
$$ | . . . X . . . X O O . X X O O . O . . |
$$ | . . . . . . . . X X . X O O O O . . . |
$$ | . . . X . . . X . , X . X X O X O O . |
$$ | . . . X . . . . X X O O X X X X X O . |
$$ | . . . . . . . X O O . 4 O 1 2 . . X O |
$$ | . . . . . . . . 8 . 3 5 . 6 . . . X . |
$$ +---------------------------------------+

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

EDIT: Also, have a look at this tsumego: http://eidogo.com/?game=1Lc8jeHa#1Lc8jeHa. The situation is similar, but black can live.

What if white plays 3 at 6?

4 at 5 works, right?

It's hard for me to prove.

There are a lot of variations from here. And maybe 5 (or 6) wasn't correct anyway.

Edit: After looking at this some more, I think white is still dead.

Posted: **Sun May 13, 2012 5:42 pm**

B looks fine to me, but I must be misreading horribly since I can't even see where the ko you mention would come from.

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

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

Four libs to three after W captures, no?

Posted: **Sun May 13, 2012 6:31 pm**

That's hard to read though. This is simpler:

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

White has only two liberties and can't do a thing about it.

Posted: **Sun May 13, 2012 7:57 pm**

jts wrote:B looks fine to me, but I must be misreading horribly since I can't even see where the ko you mention would come from.

$$Bc
$$ | O X X X O . X . O O O X . X X X O . . |
$$ | X . X . X X X O O X X X O O X O . . . |
$$ | . . . X . . . X O O . X X O O . O . . |
$$ | . . . . . . . . X X . X O O O O . . . |
$$ | . . . X . . . X . , X O X X O X O O . |
$$ | . . . X . . . . X X O O X X X X X O 8 |
$$ | . . . . . . . X O O . O O O X 6 4 X O |
$$ | . . . . . . . 3 9 2 X X . O 1 7 5 X . |
$$ +---------------------------------------+

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

$$Bc
$$ | O X X X O . X . O O O X . X X X O . . |
$$ | X . X . X X X O O X X X O O X O . . . |
$$ | . . . X . . . X O O . X X O O . O . . |
$$ | . . . . . . . . X X . X O O O O . . . |
$$ | . . . X . . . X . , X O X X O X O O . |
$$ | . . . X . . . . X X O O X X X X X O . |
$$ | . . . . . . . X O O 8 O O O X 6 4 X O |
$$ | . . . . . . . 3 2 0 X X 9 O 1 7 5 X . |
$$ +---------------------------------------+

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

Four libs to three after W captures, no?

The ko came from me overthinking the problem

Somewhere in the middle of the sequence I was playing w H1 and then b G1. Obviously b would play G2 though.

I guess the best white can do is take sente to play somewhere else, and then later come back and get a ton of ko threats out of the position by threatening to live.

Life In 19x19

Problem from One of my KGS Games

Problem from One of my KGS Games

Re: Problem from One of my KGS Games

Re: Problem from One of my KGS Games

Re: Problem from One of my KGS Games

Re: Problem from One of my KGS Games

Re: Problem from One of my KGS Games

Re: Problem from One of my KGS Games

Re: Problem from One of my KGS Games