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Offline Drew
 Post subject: Responding to a 3x3 invasion
Post #1 Posted: Tue Feb 17, 2015 1:15 am 
Lives in gote
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I'm looking for advice on handling this 3x3 invasion:

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


In a recent game we ended up as:

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


which seemed reasonable but I'm curious if there are better possible outcomes for Black?
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Offline Uberdude
 Post subject: Re: Responding to a 3x3 invasion
Post #2 Posted: Tue Feb 17, 2015 1:34 am 
Judan

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OGS: Uberdude 7d
Do you think white is alive?
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Offline Krama
 Post subject: Re: Responding to a 3x3 invasion
Post #3 Posted: Tue Feb 17, 2015 1:53 pm 
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play 7 on 2-2 in the corner and try to live with white.
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Offline EdLee
 Post subject:
Post #4 Posted: Tue Feb 17, 2015 2:01 pm 
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Krama wrote:
[jump] in the corner
Do you think that's the best move for B ?

This post by EdLee was liked by: Bill Spight
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Offline Bill Spight
 Post subject: Re:
Post #5 Posted: Tue Feb 17, 2015 2:33 pm 
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EdLee wrote:
Krama wrote:
[jump] in the corner
Do you think that's the best move for B ?


It's not a jump, it's a clamp. :)

But your question is excellent. :)

_________________
The Adkins Principle:
At some point, doesn't thinking have to go on?
— Winona Adkins

Visualize whirled peas.

Everything with love. Stay safe.
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Offline EdLee
 Post subject:
Post #6 Posted: Tue Feb 17, 2015 4:37 pm 
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Thanks, Bill. Many beginners are so happy because they spot a vital point,
and they are so excited they "jump" in the placement. So I emphasize the "jump in" bad habit. :)
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Offline Bill Spight
 Post subject: Re:
Post #7 Posted: Tue Feb 17, 2015 5:22 pm 
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EdLee wrote:
Thanks, Bill. Many beginners are so happy because they spot a vital point,
and they are so excited they "jump" in the placement. So I emphasize the "jump in" bad habit. :)


OIC. :blackeye:

_________________
The Adkins Principle:
At some point, doesn't thinking have to go on?
— Winona Adkins

Visualize whirled peas.

Everything with love. Stay safe.
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Offline Boidhre
 Post subject: Re:
Post #8 Posted: Tue Feb 17, 2015 7:15 pm 
Oza

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EdLee wrote:
Krama wrote:
[jump] in the corner
Do you think that's the best move for B ?


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


Edit: Sorry, forgot to include the reason, this seems to leave fewer ko threats for white later.
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Offline EdLee
 Post subject:
Post #9 Posted: Tue Feb 17, 2015 8:29 pm 
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Hi Boidhre,
Boidhre wrote:
ko threats for white later.
Can B do better ?
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Offline Boidhre
 Post subject: Re:
Post #10 Posted: Tue Feb 17, 2015 8:52 pm 
Oza

Posts: 2356
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Universal go server handle: Boidhre
EdLee wrote:
Hi Boidhre,
Boidhre wrote:
ko threats for white later.
Can B do better ?


Last attempt before bed:

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


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


No internal ko threat for white in either of them. I spotted :b3: alone killed when I first looked at this but it left rather a lot of moves for white to play inside for threats later.
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Offline EdLee
 Post subject:
Post #11 Posted: Wed Feb 18, 2015 5:51 am 
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Hi Boidhre,
Click Here To Show Diagram Code
[go]$$
$$ ----------------|
$$ . . . . . b . . |
$$ . . . . X O a . |
$$ . . O . X O . O |
$$ . . . . X X O . |
$$ . . . . . . X c |
$$ . . . . . . . . |
$$[/go]
Food for thought:
  • There may not be any ko the rest of the game. (We don't know yet.)
  • How useful is :black: (a) for Black for the rest of the board ?
  • Same question for :black: (b) and :black: (c).
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Offline Bill Spight
 Post subject: Re: Responding to a 3x3 invasion
Post #12 Posted: Wed Feb 18, 2015 8:25 am 
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Using my heuristic, compare

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


with

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


:)

_________________
The Adkins Principle:
At some point, doesn't thinking have to go on?
— Winona Adkins

Visualize whirled peas.

Everything with love. Stay safe.
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Offline Boidhre
 Post subject: Re:
Post #13 Posted: Wed Feb 18, 2015 10:22 am 
Oza

Posts: 2356
Location: Ireland
Liked others: 662
Was liked: 442
Universal go server handle: Boidhre
EdLee wrote:
Hi Boidhre,
Click Here To Show Diagram Code
[go]$$
$$ ----------------|
$$ . . . . . b . . |
$$ . . . . X O a . |
$$ . . O . X O . O |
$$ . . . . X X O . |
$$ . . . . . . X c |
$$ . . . . . . . . |
$$[/go]
Food for thought:
  • There may not be any ko the rest of the game. (We don't know yet.)
  • How useful is :black: (a) for Black for the rest of the board ?
  • Same question for :black: (b) and :black: (c).



b and c remove some aji from the position over just a I think. Other than that I can't see any effect on the rest of the board other than if the white group's status is left undetermined the black stones are slightly weaker. I don't know if Black should tenuki this with only seeing a corner segment.
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Offline EdLee
 Post subject:
Post #14 Posted: Wed Feb 18, 2015 2:40 pm 
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Hi Boidhre,
If :b3: at 2-2, then :w4: takes in sente -- miai of :w6: and :b5: :
Click Here To Show Diagram Code
[go]$$B
$$ ----------------|
$$ . . . . 4 1 2 . |
$$ . . . 6 X O 3 5 |
$$ . . O . X O . O |
$$ . . . . X X O . |
$$ . . . . . . X . |
$$ . . . . . . . . |
$$[/go]
Boidhre wrote:
Click Here To Show Diagram Code
[go]$$
$$ ----------------|
$$ . . . . . 1 2 . |
$$ . . . . X O 4 3 |
$$ . . O . X O . O |
$$ . . . . X X O . |
$$ . . . . . . X 5 |
$$ . . . . . . . . |
$$ . . . . . . . . |
$$ . . . . . . . . |
$$[/go]
Above var, instead of connecting at :w4: ...
:w1: takes in sente:
Click Here To Show Diagram Code
[go]$$W
$$ ----------------|
$$ . . . . 1 B O 7 |
$$ . . . 2 X O 5 B |
$$ . . O . X O . O |
$$ . . . . X X O 8 |
$$ . . . . . . X 3 |
$$ . . . . . . 4 6 |
$$ . . . . . . . . |
$$ . . . . . . . . |
$$[/go]

Conclusion: :b1: hane is not a correct move.

This post by EdLee was liked by: Boidhre
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Offline EdLee
 Post subject:
Post #15 Posted: Wed Feb 18, 2015 7:02 pm 
Honinbo
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Hi Boidhre,
Click Here To Show Diagram Code
[go]$$
$$ ----------------|
$$ . . . . . . b . |
$$ . . . . X O a . |
$$ . . O . X O . O |
$$ . . . . X X O . |
$$ . . . . . d X c |
$$ . . . . . . . . |
$$[/go]
Locally, each of :black: (a), :black: (b), and :black: (c) kills.

:black: (a) and :black: (b) are about the same.

:black: (c) -- B has to be careful, because this involves B's liberties,
and B has to watch out later, if the (d) ladder becomes good for W.

So perhaps the placement :black: (b) and clamp :black: (a) are slightly better.

Globally, it depends. Re: Bill, post 12. :)
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Offline Boidhre
 Post subject: Re: Responding to a 3x3 invasion
Post #16 Posted: Wed Feb 18, 2015 7:15 pm 
Oza

Posts: 2356
Location: Ireland
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Universal go server handle: Boidhre
Thanks Ed, it's been an interesting dissection and shown up some blind spots for me. :)
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Offline EdLee
 Post subject:
Post #17 Posted: Wed Feb 18, 2015 11:33 pm 
Honinbo
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Boidhre wrote:
blind spots for me. :)
Same here. :mrgreen:
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