Cutting point in 3-3 invasion joseki

PeterPeter · Post by **PeterPeter** » Sat Oct 13, 2012 1:02 am

A position from the interesting Malkovich game #158:

Click Here To Show Diagram Code: [go]$$Bcm11 W:0 B:0 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . X . . . . | $$ | . . . , . . . . . , . . . . . , X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , O . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . O O . | $$ | . . X . . . . . . . . . . . . b O X . | $$ | . . . , . . . . . , . . . . . O X . X | $$ | . . . X . . . . . O . . . 0 a O X . . | $$ | . . . . . . . . . . . . . . O X 9 . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Probably a basic question, but why was

played here? Couldn't White play elsewhere, then if Black cut at A, trap him in an inescapable ladder by then playing that move? Why is cutting point A more important than cutting point B?

PeterPeter · Post by **PeterPeter** » Sat Oct 13, 2012 1:05 am

Don't worry, I have just seen it: Black can escape from the ladder by capturing the 2 Black stones!

EdLee · Post by **EdLee** » Sat Oct 13, 2012 1:07 am

Peter, first of all,

(T4) was a mistake, and not joseki.
The result is too good for W -- so don't learn this as a 'joseki'.
Second, could you show your sequence if B cuts at (b)?
This will answer your last question why W fixed (a) but not (b).

PeterPeter · Post by **PeterPeter** » Sat Oct 13, 2012 1:22 am

EdLee wrote:Peter, first of all, (T4) was a mistake, and not joseki.

That move looked odd to me, but I was giving the player (who is much stronger than I am) the benefit of the doubt. Thanks for pointing out something that I should NOT try to learn from.

EdLee wrote:Second, could you show your sequence if B cuts at (b)?
(This will answer your question why W fixed the cut at (a) but not at (b)).

I think I have answered my own question: Black can escape from a ladder at A, but not from one at B?

EdLee · Post by **EdLee** » Sat Oct 13, 2012 1:23 am

PeterPeter wrote:Black can escape from a ladder at A, but not from one at B?

It sounds like you figured out what happens if B cuts at (a).
Now please show us (and other beginners) the sequence you figured out if B cuts at (b).

PeterPeter · Post by **PeterPeter** » Sat Oct 13, 2012 1:42 am

Click Here To Show Diagram Code: [go]$$Bcm19 W:0 B:0 $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . X . . . . | $$ | . . . , . . . . . , . . . . . , X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , O . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . 0 . . . . | $$ | . . . . . . . . . . . . . . 9 6 . . . | $$ | . . . . . . . . . . . . . 8 7 5 O O . | $$ | . . X . . . . . . . . . . . 4 3 O X . | $$ | . . . , . . . . . , . . . . . O X . X | $$ | . . . X . . . . . O . . . 2 . O X . . | $$ | . . . . . . . . . . . . . . O X 1 . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Am I missing something? I don't see a good outcome for Black after

?

EdLee · Post by **EdLee** » Sat Oct 13, 2012 1:45 am

PeterPeter wrote:Am I missing something?

Yes.

Your sequence fails for W if there was a B stone at C17. Try again.

In other words, if we change to following board, W would still play

to fix (a), and not (b) -- why??

Click Here To Show Diagram Code: [go]$$W $$ ----------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . X . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . O O . | $$ | . . . . . . . . . . . . . . . b O X . | $$ | . . . , . . . . . , . . . . . O X . X | $$ | . . . . . . . . . . . . . 1 a O X . . | $$ | . . . . . . . . . . . . . . O X X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ -----------------------------------------[/go]

PeterPeter · Post by **PeterPeter** » Sat Oct 13, 2012 2:02 am

Oh I see. I don't see an escape for Black from this net:

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

EdLee · Post by **EdLee** » Sat Oct 13, 2012 2:08 am

Very good!

Now you understand

better in that game.
Here is one joseki -- W also plays

to fix (a), but not (b) -- why?

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

PeterPeter · Post by **PeterPeter** » Sat Oct 13, 2012 2:18 am

This looks very similar. White could set a net at c.

Click Here To Show Diagram Code: [go]$$B $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . 2 . . | $$ | . . . . . . . . . . . . . . c . O 1 . | $$ | . . . . . . . . . . . . . . . b O X . | $$ | . . . , . . . . . , . . . . . O X . . | $$ | . . . . . . . . . . . . . 6 a O X . . | $$ | . . . . . . . . . . . . . . 4 3 5 . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ -----------------------------------------[/go]

EdLee · Post by **EdLee** » Sat Oct 13, 2012 2:21 am

Good. Follow-up question: what about

? Can B escape with

?

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

PeterPeter · Post by **PeterPeter** » Sat Oct 13, 2012 2:27 am

White would set a net with

.

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

EdLee · Post by **EdLee** » Sat Oct 13, 2012 2:28 am

Yes -- what if B ataris with

?

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

PeterPeter · Post by **PeterPeter** » Sat Oct 13, 2012 3:02 am

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

White will connect with

, then Black can escape at

(escaping at A fails after White B). White will capture with

, and I slightly prefer White's position.

I had to consider a lot of variations to decide on this main line - how did I do?

EdLee · Post by **EdLee** » Sat Oct 13, 2012 3:14 am

was bad -- try again.

PeterPeter wrote:White will capture with , and I slightly prefer White's position.
$$B
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . 4 . O . . |
$$ | . . . . . . . . . . . . . 9 7 3 O X . |
$$ | . . . . . . . . . . . . . . 2 1 O X . |
$$ | . . . , . . . . . , . . . 8 C O X . . |
$$ | . . . . . . . . . . . . . O 6 O X . . |
$$ | . . . . . . . . . . . . . . O X X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ -----------------------------------------
Click Here To Show Diagram Code
[go]$$B $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . 4 . O . . | $$ | . . . . . . . . . . . . . 9 7 3 O X . | $$ | . . . . . . . . . . . . . . 2 1 O X . | $$ | . . . , . . . . . , . . . 8 C O X . . | $$ | . . . . . . . . . . . . . O 6 O X . . | $$ | . . . . . . . . . . . . . . O X X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ -----------------------------------------[/go]

This shape is a disaster for W.

Life In 19x19

Cutting point in 3-3 invasion joseki

Cutting point in 3-3 invasion joseki

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Re: Cutting point in 3-3 invasion joseki

Re: Cutting point in 3-3 invasion joseki

Re: Cutting point in 3-3 invasion joseki

Re: Cutting point in 3-3 invasion joseki

Re: Cutting point in 3-3 invasion joseki