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What to do

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What to do

Posted: Tue Oct 11, 2016 4:40 pm
by dfan
Here's an interesting situation from a tournament game I played on Sunday. I'm Black with a 3-stone handicap. White has just played the marked stone. How would you respond and what do you think the next few moves will be? I'll post the actual game continuation later.

At the time this game was played, I was 4k and my opponent was 1k (AGA), though we both entered the tournament one rank higher :)
Click Here To Show Diagram Code
[go]$$Bc B to play
$$ |---------------------------------------|
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . X O . O . O O . . . |
$$ | . . . . . . . . . X O . . O X O X . . |
$$ | . . X X . . . . . , X O O X X X . . . |
$$ | . . O . . . . . . X . X X X . . . . . |
$$ | . . O X X . . . . . . . . . . . . . . |
$$ | . . . O X . . . . . . . . . . X . . . |
$$ | . . O . O X X . . . . . . . . . . . . |
$$ | . . . . O O . . . . O . O . . . X X . |
$$ | . . . , . . . O . , . . O X . X O . . |
$$ | . . . . . . . . . . . X O . . . O . . |
$$ | . . . . X . . . . . . X . O . O . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . O X . . . . . . . . . . . . . . . |
$$ | . . . X . . . . O . . X . X . X . . . |
$$ | . . O X . X . . . , . . . . . , X . . |
$$ | . . O . X O X . O . . O . O . O X . . |
$$ | . . . . . W . . . . . . . . . . O X . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ |---------------------------------------|[/go]

Re: What to do

Posted: Tue Oct 11, 2016 4:58 pm
by DrStraw
I just glanced at it quickly without much analysis, but here was my first reaction, followed by a. I wouldn't play that in a tournament without more analysis, but I probably would in a fast online game.
Click Here To Show Diagram Code
[go]$$Bc B to play
$$ |---------------------------------------|
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . X O . O . O O . . . |
$$ | . . . . . . . . . X O . . O X O X . . |
$$ | . . X X . . . . . , X O O X X X . . . |
$$ | . . O . . . . . . X . X X X . . . . . |
$$ | . . O X X . . . . . . . . . . . . . . |
$$ | . . . O X . . . . . . . . . . X . . . |
$$ | . . O . O X X . . . . . . . . . . . . |
$$ | . . . . O O . . . . O . O . . . X X . |
$$ | . . . , . . . O . , . . O X . X O . . |
$$ | . . . . . . . . . . . X O . . . O . . |
$$ | . . 9 . X . . . . . . X . O . O . . . |
$$ | . 0 O a . . . . . . . . . . . . . . . |
$$ | . 3 O X . . . . . . . . . . . . . . . |
$$ | . 2 1 X . . . . O . . X . X . X . . . |
$$ | . 4 O X . X . 7 8 , . . . . . , X . . |
$$ | . . O . X O X . O . . O . O . O X . . |
$$ | . . . . 6 O 5 . . . . . . . . . O X . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ |---------------------------------------|[/go]

Re: What to do

Posted: Wed Oct 12, 2016 8:54 pm
by lightvector
My own thought after a little bit of staring at the position was this:
Click Here To Show Diagram Code
[go]$$Bc B thoughts
$$ |---------------------------------------|
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . X O . O . O O . . . |
$$ | . . . . . . . . . X O . . O X O X . . |
$$ | . . X X . . . . . , X O O X X X . . . |
$$ | . . O . . . . . . X . X X X . . . . . |
$$ | . . O X X . . . . . . . . . . . . . . |
$$ | . . . O X . . . . . . . . . . X . . . |
$$ | . . O . O X X . . . . . . . . . . . . |
$$ | . . . . O O . . . . O . O . . . X X . |
$$ | . . . , . . . O . , . . O X . X O . . |
$$ | . . . . . . . . . . . X O . . . O . . |
$$ | . . a . X . . . . . . X . O . O . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . 3 O X . . . . . . . . . . . . . . . |
$$ | . 2 1 X . . . . O . . X . X . X . . . |
$$ | . 4 O X . X T . . , . . . . . , X . . |
$$ | . . O . X O X 5 O . . O . O . O X . . |
$$ | . . . . 6 O . . . . . . . . . . O X . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ |---------------------------------------|[/go]
Yay I got the same first four moves. Is :b5: plausible as an alternative? Actually, assuming white has nothing better to do than :w6: I don't actually know where black's next move would be - I feel like black still is concerned about protecting the triangled cutting point even after this, but maybe it's enough to do so and just let white owe a response to the bump.

As a bit of exposition for beginners about the first four moves in case it's not clear, the idea behind the push and cut is to get a free stone at B6 as aji to enable a later possible forcing move at "a", as in DrStraw's sequence. If white engulfs that stone with :w4: to deny black that aji instead of connecting, then we get the below sequence. But this sequence won't work if black waits any longer and F2 has already connected up, which means black needs to take advantage right now before the chance goes away.
Click Here To Show Diagram Code
[go]$$Bc Yummy white group
$$ |---------------------------------------|
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . X O . O . O O . . . |
$$ | . . . . . . . . . X O . . O X O X . . |
$$ | . . X X . . . . . , X O O X X X . . . |
$$ | . . O . . . . . . X . X X X . . . . . |
$$ | . . O X X . . . . . . . . . . . . . . |
$$ | . . . O X . . . . . . . . . . X . . . |
$$ | . . O . O X X . . . . . . . . . . . . |
$$ | . . . . O O . . . . O . O . . . X X . |
$$ | . . . , . . . O . , . . O X . X O . . |
$$ | . . . . . . . . . . . X O . . . O . . |
$$ | . . . . X . . . . . . X . O . O . . . |
$$ | . 4 O . . . . . . . . . . . . . . . . |
$$ | 6 3 O X . . . . . . . . . . . . . . . |
$$ | . 2 1 X . . . . O . . X . X . X . . . |
$$ | . 5 O X . X . . . , . . . . . , X . . |
$$ | . 8 O . X W X . O . . O . O . O X . . |
$$ | . . 7 . . W 9 . . . . . . . . . O X . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ |---------------------------------------|[/go]

Re: What to do

Posted: Thu Oct 13, 2016 1:53 am
by mongus
lightvector wrote: As a bit of exposition for beginners about the first four moves in case it's not clear, the idea behind the push and cut is to get a free stone at B6 as aji to enable a later possible forcing move at "a", as in DrStraw's sequence. If white engulfs that stone with :w4: to deny black that aji instead of connecting, then we get the below sequence. But this sequence won't work if black waits any longer and F2 has already connected up, which means black needs to take advantage right now before the chance goes away.
Interesting. So essentially this works because you have a wall of three against a wall with a hole and two stones on either side?
Click Here To Show Diagram Code
[go]$$Bc
$$ | . . a . . . .
$$ | . . O . . . .
$$ | . . O X . . .
$$ | . . . X . . .
$$ | . . O X . . .
$$ | . . O . . . .
$$ | . . b . . . .
$$ | . . . . . . .[/go]
You can then get a choice of a free move at a or b. That is a pattern well worth remembering. Thanks.

Re: What to do

Posted: Thu Oct 13, 2016 2:55 am
by Uberdude
mongus, that's the basic idea, but your diagram is a bit too general with too much open space: in your diagram if black plays b white just turns and splits and walks into the joyful fields of liberties and sunshine. So black needs something around there too. (Also b is usually near the edge of the board). See this joseki for example: http://josekipedia.com/#path:qepcodocndmc and also similar ones starting with 3-4, some pincer and then the press.

Re: What to do

Posted: Thu Oct 13, 2016 4:49 am
by dfan
Thanks for the replies! This makes it clear that I have something to work on. Both of you (apparently) immediately gave up on the F3/F2 stones, except perhaps as a threat, and worked on using the existing threats to stabilize the black group.

I had already (incorrectly) decided the F3 stone was captured, and freaked out when White extended, unable to get out of the mindset of "I have to capture those stones!".

The next few moves:
Click Here To Show Diagram Code
[go]$$Bc
$$ |---------------------------------------|
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . X O . O . O O . . . |
$$ | . . . . . . . . . X O . . O X O X . . |
$$ | . . X X . . . . . , X O O X X X . . . |
$$ | . . O . . . . . . X . X X X . . . . . |
$$ | . . O X X . . . . . . . . . . . . . . |
$$ | . . . O X . . . . . . . . . . X . . . |
$$ | . . O . O X X . . . . . . . . . . . . |
$$ | . . . . O O . . . . O . O . . . X X . |
$$ | . . . , . . . O . , . . O X . X O . . |
$$ | . . . . . . . . . . . X O . . . O . . |
$$ | . . . . X . . . . . . X . O . O . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . O X . . . . . . . . . . . . . . . |
$$ | . . . X . . . . O . . X . X . X . . . |
$$ | . . O X . X . . . , . . . . . , X . . |
$$ | . . O 3 X O X . O . . O . O . O X . . |
$$ | . 5 1 4 2 O . . . . . . . . . . O X . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ |---------------------------------------|[/go]

Re: What to do

Posted: Thu Oct 13, 2016 5:25 am
by Uberdude
dfan, who do you think you diagram is good for at the end?

Answer:
Black. White is in big trouble. He should have simply played 2 at g2 and black doesn't have any particularly amazing followup. c2 is a nice idea though, retaining the aji of the 2 forcing moves there. Now if white plays b3 trying to defend the cut and take a liberty to stop black g2 from winning the race then black a2 is a tesuji to gain liberties and white can't take a lib at a3 or c5, and if g2 then push and throw in is the tesuji to capture.

Re: What to do

Posted: Thu Oct 13, 2016 6:23 am
by dfan
Uberdude wrote:dfan, who do you think you diagram is good for at the end?
I was certainly happy about it at the time, although things went a little sour a bit later. I had a different response to B3, which I thought worked (and still do), though I'd be happy to learn if it wasn't optimal.

Coming up: Part III: White Fights Back
Click Here To Show Diagram Code
[go]$$Wc
$$ |---------------------------------------|
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . X O . O . O O . . . |
$$ | . . . . . . . . . X O . . O X O X . . |
$$ | . . X X . . . . . , X O O X X X . . . |
$$ | . . O . . . . . . X . X X X . . . . . |
$$ | . . O X X . . . . . . . . . . . . . . |
$$ | . . . O X . . . . . . . . . . X . . . |
$$ | . . O . O X X . . . . . . . . . . . . |
$$ | . . . . O O . . . . O . O . . . X X . |
$$ | . . . , . . . O . , . . O X . X O . . |
$$ | . . . . . . . . . . . X O . . . O . . |
$$ | . . . . X . . . . . . X . O . O . . . |
$$ | . 7 O . . . . . . . . . . . . . . . . |
$$ | . 6 O X . . . . . . . . . . . . . . . |
$$ | . 3 2 X . . . . O . . X . X . X . . . |
$$ | . 5 O X . X . . . , . . . . . , X . . |
$$ | 4 1 O X X O X . O . . O . O . O X . . |
$$ | . X X O O O 8 . . . . . . . . . O X . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ |---------------------------------------|[/go]
If White had played at G2, I had something like this in mind, although I guess all it really does is take a few points and make half an eye. So I'm lucky he responded as he did :)
Click Here To Show Diagram Code
[go]$$Bc
$$ |---------------------------------------|
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . X O . O . O O . . . |
$$ | . . . . . . . . . X O . . O X O X . . |
$$ | . . X X . . . . . , X O O X X X . . . |
$$ | . . O . . . . . . X . X X X . . . . . |
$$ | . . O X X . . . . . . . . . . . . . . |
$$ | . . . O X . . . . . . . . . . X . . . |
$$ | . . O . O X X . . . . . . . . . . . . |
$$ | . . . . O O . . . . O . O . . . X X . |
$$ | . . . , . . . O . , . . O X . X O . . |
$$ | . . . . . . . . . . . X O . . . O . . |
$$ | . . . . X . . . . . . X . O . O . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . O X . . . . . . . . . . . . . . . |
$$ | . 4 3 X . . . . O . . X . X . X . . . |
$$ | . 5 O X . X . . . , . . . . . , X . . |
$$ | . 6 O . X O X . O . . O . O . O X . . |
$$ | . 7 1 . . O 2 . . . . . . . . . O X . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ |---------------------------------------|[/go]

Re: What to do

Posted: Sat Oct 15, 2016 8:00 am
by dfan
A couple updates after spending a little time with Crazy Stone:

1. The position in the real game after I played at B2 (where Uberdude said that White is big trouble) is actually not so terrible for White if he sacrifices his four stones:
Click Here To Show Diagram Code
[go]$$Wc
$$ |---------------------------------------|
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . X O . O . O O . . . |
$$ | . . . . . . . . . X O . . O X O X . . |
$$ | . . X X . . . . . , X O O X X X . . . |
$$ | . . O . . . . . . X . X X X . . . . . |
$$ | . . O X X . . . . . . . . . . . . . . |
$$ | . . . O X . . . . . . . . . . X . . . |
$$ | . . O . O X X . . . . . . . . . . . . |
$$ | . . . . O O . . . . O . O . . . X X . |
$$ | . . . , . . . O . , . . O X . X O . . |
$$ | . . . . . . . . . . . X O . . . O . . |
$$ | . . . . X . . . . . . X . O . O . . . |
$$ | . . O 7 9 . . . . . . . . . . . . . . |
$$ | . . O X 8 . . . . . . . . . . . . . . |
$$ | . . 1 X . 5 . . O . . X . X . X . . . |
$$ | . . O X 6 X 3 . . , . . . . . , X . . |
$$ | . . O X X O X . O . . O . O . O X . . |
$$ | . X X O O O 2 . . . . . . . . . O X . |
$$ | . . . . . 4 . . . . . . . . . . . . . |
$$ |---------------------------------------|[/go]
These weaknesses cropped up in the actual game as well.

2. In my proposed followup if White had played at G2 in response to C2:
Click Here To Show Diagram Code
[go]$$Bc
$$ |---------------------------------------|
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . X O . O . O O . . . |
$$ | . . . . . . . . . X O . . O X O X . . |
$$ | . . X X . . . . . , X O O X X X . . . |
$$ | . . O . . . . . . X . X X X . . . . . |
$$ | . . O X X . . . . . . . . . . . . . . |
$$ | . . . O X . . . . . . . . . . X . . . |
$$ | . . O . O X X . . . . . . . . . . . . |
$$ | . . . . O O . . . . O . O . . . X X . |
$$ | . . . , . . . O . , . . O X . X O . . |
$$ | . . . . . . . . . . . X O . . . O . . |
$$ | . . . . X . . . . . . X . O . O . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . O X . . . . . . . . . . . . . . . |
$$ | . 4 3 X . . . . O . . X . X . X . . . |
$$ | . 5 O X . X . . . , . . . . . , X . . |
$$ | . 6 O . X O X . O . . O . O . O X . . |
$$ | . 7 1 . . O 2 . . . . . . . . . O X . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ |---------------------------------------|[/go]
I should have omitted the 5-6 pair (standard "omit the 1-2 in 1-2-3" reasoning). Since the position didn't actually come up, I'm not sure what I would have played in reality if we got here.
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