Life In 19x19

Here are some examples of this split shape and the big ko from recent play:

This one is quite common in using the d5 attachment and so on as ko threats, this shape often appears with the Chinese opening. Also note that even after white connects the ko, black later lives in the corner (sometimes doing so can even threaten the eyes of the big white wall).


First using threats in top right joseki, and then manufacturing a ko threat factory with attachment and crosscut.


This one they don't fight the ko much but resolve it locally: black gets a nice outside wall and the corner, whilst the splitting white group squirms around and lives.

Bill Spight wrote:Look again. The last diagram is significantly different from the previous one.

Sure, it's a little different. It's not clear to me whether living in the corner is better, or if taking Q17 is better. I only know the other shape. Still, the crosscut should be playable, I think.

Jesus, Kirby! You know I'm trying to help you, right?

Kirby wrote:As I understand it, this is a common variation these days:

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

Click Here To Show Diagram Code

[go]$$Wc
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 9 7 . |
$$ | . . . . . . . . . . X . . . . 8 3 4 . |
$$ | . . . X . . . . . , . . . . O 0 X 5 . |
$$ | . . . . . . . . . . . . . . . . 6 . . |
$$ | . . . . . . . . . . . . . . 1 X . . . |
$$ | . . . . . . . . . . . . . . 2 . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |[/go]

{snip}

If we consider the same line of thinking, just living in the corner would also seem similar with the given refutation.

$$Wc Black's counter
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . b 9 7 . |
$$ | . . . . . . . . . . X . . . . 8 3 4 . |
$$ | . . . X . . . . . , . . . . O 6 X 5 . |
$$ | . . . . . . . . . . . . . . . . 0 a . |
$$ | . . . . . . . . . . . . . . 1 X . . . |
$$ | . . . . . . . . . . . . . . 2 . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |

Click Here To Show Diagram Code

[go]$$Wc Black's counter
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . b 9 7 . |
$$ | . . . . . . . . . . X . . . . 8 3 4 . |
$$ | . . . X . . . . . , . . . . O 6 X 5 . |
$$ | . . . . . . . . . . . . . . . . 0 a . |
$$ | . . . . . . . . . . . . . . 1 X . . . |
$$ | . . . . . . . . . . . . . . 2 . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |[/go]

Black could block at 'a', but white could perhaps counter with 'b' next.

If you were Black, would you play in the second diagram? (Diagram edited by me.) Of course not. As you indicate by suggesting "a". But is what it would take to transpose to the first diagram, which you consider to lead to an even exchange.

The second diagram (without ) is better for Black, which means that is a mistake.

Bill Spight wrote:Jesus, Kirby! You know I'm trying to help you, right?

I'm sorry, Bill. It's not my intention to offend you.

I guess your analysis makes sense, too. The only thing I really knew about this position was one variation, which I showed. From this I concluded that the cross-cut is still playable - which seems logical to me.

It looks like I was wrong on how to react in the variation that followed, and maybe there is a better way. Please don't be angry with me, though...

Kirby wrote:

Bill Spight wrote:Jesus, Kirby! You know I'm trying to help you, right?

I'm sorry, Bill. It's not my intention to offend you.

I guess your analysis makes sense, too. The only thing I really knew about this position was one variation, which I showed. From this I concluded that the cross-cut is still playable - which seems logical to me.

It looks like I was wrong on how to react in the variation that followed, and maybe there is a better way. Please don't be angry with me, though...

Kirby, I am not angry with you, or offended. Just exasperated.

I don't think that you gave much thought to the difference between the two lines of play. is a game losing play.

Compare: joseki result, with white sente:

Click Here To Show Diagram Code

[go]$$Wcm11
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . 5 O O . |
$$ | . . . . . . . . . . X . . . 6 X O X . |
$$ | . . . X . . . . . , . . . . O X X O . |
$$ | . . . . . . . . . . . . . . . . X 1 . |
$$ | . . . . . . . . . . . . . . O X 4 2 . |
$$ | . . . . . . . . . . . . . . X . 3 . . |
$$ | . . . . . . . . . . . . . . . . . . . |[/go]

with this and black sente:

Click Here To Show Diagram Code

[go]$$Wc
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . 7 5 3 . |
$$ | . . . . . . . . . . X . . . 8 4 O X 9 |
$$ | . . . X . . . . . , . . . . O 2 X 1 . |
$$ | . . . . . . . . . . . . . . . . . 6 . |
$$ | . . . . . . . . . . . . . . O X . . . |
$$ | . . . . . . . . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |[/go]

Bill Spight wrote: Kirby, I am not angry with you, or offended. Just exasperated.

I don't think that you gave much thought to the difference between the two lines of play. is a game losing play.

Okay. I can understand your reasoning when it is spoon-fed to me, but I don't know if I could have come to the same conclusion by myself.

Anyway, I agree with you about the position.

Uberdude wrote:@Bill, allowing the split and fighting a huge ko was pretty popular a year or two ago, I haven't seen it so much recently (whether that's just fashion or they decided it's good for someone I don't know, or maybe I'm just not looking at the games it still happens in). In fact white preferred the more powerful atari here, the simple connection is slack so play went like this.

$$Wc Broken shape
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 8 . . |
$$ | . . . . . . . . . . X . . . . 6 W X . |
$$ | . . . X . . . . . , . . . . O 9 X O . |
$$ | . . . . . . . . . . . . . . . . 7 . . |
$$ | . . . . . . . . . . . . . 0 O X . . . |
$$ | . . . . . . . . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |

Click Here To Show Diagram Code

[go]$$Wc Broken shape
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 8 . . |
$$ | . . . . . . . . . . X . . . . 6 W X . |
$$ | . . . X . . . . . , . . . . O 9 X O . |
$$ | . . . . . . . . . . . . . . . . 7 . . |
$$ | . . . . . . . . . . . . . 0 O X . . . |
$$ | . . . . . . . . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |[/go]

Just want to mention that this sequence happened on the very first pro game that I am trying to memorize:

https://badukmovies.com/pro_games/48253 ... kim-dongho