It is currently Mon May 05, 2025 1:47 am

View unanswered posts | View active topics View unread posts | View new posts | View your posts


Board index » Improve Your Game » Study Group

All times are UTC - 8 hours [ DST ]



Post new topic Reply to topic  Page 1 of 1
  [ 17 posts ] 
  Print view Previous topic | Next topic 
Author Message
Offline oca
 Post subject: One space corner extension invasion question
Post #1 Posted: Fri Jun 20, 2014 7:02 am 
Lives in gote
User avatar

Posts: 699
Location: Switzerland
Liked others: 485
Was liked: 166
Rank: DDK
KGS: aco
IGS: oca
OGS: oca
Hi,
I saw in book an invasion that went like that :

Click Here To Show Diagram Code
[go]$$W
$$ ----------------+
$$ . . . . . . . . |
$$ . . 8 7 9 . . . |
$$ . . . 2 1 5 c . |
$$ . . . B 3 B b . |
$$ . . . a 4 6 . . |
$$ . . . . . . . . |
$$ . . . . . . . . |
$$ . . . . . . . . |[/go]


Then they talk about continuation for :b10: at "a" and "b", but nothing is said about :b10: at "c"
Trying for my self I went to this where white lives...
Is my sequence correct ? Is there anything better for black (or for white) ?

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


Any thought is welcome...

_________________
Converting the book Shape UP! by Charles Matthews/Seong-June Kim
to the gobook format. last updated april 2015 - Index of shapes, p.211 / 216
Top
 Profile  
 
Offline DrStraw
 Post subject: Re: One space corner extension invasion question
Post #2 Posted: Fri Jun 20, 2014 7:06 am 
Oza

Posts: 2180
Location: ʍoquıɐɹ ǝɥʇ ɹǝʌo 'ǝɹǝɥʍǝɯos
Liked others: 237
Was liked: 662
Rank: AGA 5d
GD Posts: 4312
Online playing schedule: Every tenth February 29th from 20:00-20:01 (if time permits)
You have found the sequence which invalidates a black move at c

_________________
Still officially AGA 5d but I play so irregularly these days that I am probably only 3d or 4d over the board (but hopefully still 5d in terms of knowledge, theory and the ability to contribute).


Last edited by DrStraw on Fri Jun 20, 2014 7:11 am, edited 1 time in total.
Top
 Profile  
 
Offline Joaz Banbeck
 Post subject: Re: One space corner extension invasion question
Post #3 Posted: Fri Jun 20, 2014 7:08 am 
Judan
User avatar

Posts: 5546
Location: Banbeck Vale
Liked others: 1104
Was liked: 1457
Rank: 1D AGA
GD Posts: 1512
Kaya handle: Test
oca wrote:
...
Click Here To Show Diagram Code
[go]$$B
$$ ----------------+
$$ . . 9 7 0 5 6 . |
$$ . . X O O 8 2 4 |
$$ . . . X O O 1 . |
$$ . . . B O B 3 . |
$$ . . . . X X . . |
$$ . . . . . . . . |
$$ . . . . . . . . |[/go]

...


Black can start a ko like this. It is not easy for black to win because of his cutting points, but white has to win to live.

Click Here To Show Diagram Code
[go]$$B
$$ ----------------+
$$ . . . . 0 . . . |
$$ . . X O O . 2 3 |
$$ . . . X O O 1 . |
$$ . . . X O X 4 5 |
$$ . . . . X X . . |
$$ . . . . . . . . |
$$ . . . . . . . . |[/go]

_________________
Help make L19 more organized. Make an index: https://lifein19x19.com/viewtopic.php?f=14&t=5207
Top
 Profile  
 
Offline DrStraw
 Post subject: Re: One space corner extension invasion question
Post #4 Posted: Fri Jun 20, 2014 7:12 am 
Oza

Posts: 2180
Location: ʍoquıɐɹ ǝɥʇ ɹǝʌo 'ǝɹǝɥʍǝɯos
Liked others: 237
Was liked: 662
Rank: AGA 5d
GD Posts: 4312
Online playing schedule: Every tenth February 29th from 20:00-20:01 (if time permits)
I don't think that this ko is even worth considering this early in the game as there is almost certain no threat big enough. Later in the game it may be a possibility.

_________________
Still officially AGA 5d but I play so irregularly these days that I am probably only 3d or 4d over the board (but hopefully still 5d in terms of knowledge, theory and the ability to contribute).
Top
 Profile  
 
Offline Joaz Banbeck
 Post subject: Re: One space corner extension invasion question
Post #5 Posted: Fri Jun 20, 2014 7:15 am 
Judan
User avatar

Posts: 5546
Location: Banbeck Vale
Liked others: 1104
Was liked: 1457
Rank: 1D AGA
GD Posts: 1512
Kaya handle: Test
DrStraw wrote:
I don't think that this ko is even worth considering this early in the game as there is almost certain no threat big enough. Later in the game it may be a possibility.


Agreed. So black probably tenukis at 3, and gets sente.

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


Later, if white wants to repair it, he loses sente again:

Click Here To Show Diagram Code
[go]$$Wm96
$$ ----------------+
$$ . . . . . . . . |
$$ . . X O O . O . |
$$ . . . X O O X 3 |
$$ . . . X O X 1 . |
$$ . . . . X X 2 . |
$$ . . . . . . . . |
$$ . . . . . . . . |[/go]


So black can leave it until he has good ko theats, and until he does, it is always going to be a pile of bad aji for white.

_________________
Help make L19 more organized. Make an index: https://lifein19x19.com/viewtopic.php?f=14&t=5207
Top
 Profile  
 
Offline oca
 Post subject: Re: One space corner extension invasion question
Post #6 Posted: Fri Jun 20, 2014 7:34 am 
Lives in gote
User avatar

Posts: 699
Location: Switzerland
Liked others: 485
Was liked: 166
Rank: DDK
KGS: aco
IGS: oca
OGS: oca
Thanks, that's very interesting, variants with ko never comes into my mind...

_________________
Converting the book Shape UP! by Charles Matthews/Seong-June Kim
to the gobook format. last updated april 2015 - Index of shapes, p.211 / 216
Top
 Profile  
 
Offline Uberdude
 Post subject: Re: One space corner extension invasion question
Post #7 Posted: Fri Jun 20, 2014 7:47 am 
Judan

Posts: 6727
Location: Cambridge, UK
Liked others: 436
Was liked: 3720
Rank: UK 4 dan
KGS: Uberdude 4d
OGS: Uberdude 7d
oca, as you showed with your sequence connecting with 3 doesn't kill the corner. But even if it did (locally) you need to realize there is a big weakness in black's surrounding position with this cut of 4.

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


If white captures part of black's wall he lives easily and escapes and destroys black's outside influence. Now it may be that black just about manages to keep everything together but at a minimum it means the ko Joaz showed is utterly unplayable for black as white has loads of local threats. That's why the book recommended connecting at a (now the cut of 4 above can be captured in a ladder, or if no ladder the fight is now much easier for black). It's a very common beginner (and not beginner!) mistake to only look at the opponent's problems and try to kill something, only for them to counterattack and exploit your weaknesses you overlooked and kill some of you instead.

This post by Uberdude was liked by: oca
Top
 Profile  
 
Offline Uberdude
 Post subject: Re: One space corner extension invasion question
Post #8 Posted: Fri Jun 20, 2014 7:54 am 
Judan

Posts: 6727
Location: Cambridge, UK
Liked others: 436
Was liked: 3720
Rank: UK 4 dan
KGS: Uberdude 4d
OGS: Uberdude 7d
Joaz Banbeck wrote:

Later, if white wants to repair it, he loses sente again:

Click Here To Show Diagram Code
[go]$$Wm96
$$ ----------------+
$$ . . . . . . . . |
$$ . . X O O . O . |
$$ . . . X O O X 3 |
$$ . . . X O X 1 . |
$$ . . . a X X 2 . |
$$ . . . . . . . . |
$$ . . . . . . . . |[/go]



Actually white can tennuki after black 97 and he has elimnated in the ko in sente already (though at the cost of making a bad exchange as if black then captures the stone and white answers that capture made him stronger). If black doesn't want white to fix in sente he has to tenuki 96 but then if white crawls at 97 it takes a liberty and the cut at a becomes very serious.
Top
 Profile  
 
Offline oca
 Post subject: Re: One space corner extension invasion question
Post #9 Posted: Fri Jun 20, 2014 8:00 am 
Lives in gote
User avatar

Posts: 699
Location: Switzerland
Liked others: 485
Was liked: 166
Rank: DDK
KGS: aco
IGS: oca
OGS: oca
Uberdude wrote:
oca, as you showed with your sequence connecting with 3 doesn't kill the corner. But even if it did (locally) you need to realize there is a big weakness in black's surrounding position with this cut of 4.

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


If white captures part of black's wall he lives easily and escapes and destroys black's outside influence. Now it may be that black just about manages to keep everything together but at a minimum it means the ko Joaz showed is utterly unplayable for black as white has loads of local threats. That's why the book recommended connecting at a (now the cut of 4 above can be captured in a ladder, or if no ladder the fight is now much easier for black). It's a very common beginner (and not beginner!) mistake to only look at the opponent's problems and try to kill something, only for them to counterattack and exploit your weaknesses you overlooked and kill some of you instead.


:o Wow ... the ladder doesn't work... back to "Lessons In The Fundamentals Of Go" Chapter 1 ;-) ...

_________________
Converting the book Shape UP! by Charles Matthews/Seong-June Kim
to the gobook format. last updated april 2015 - Index of shapes, p.211 / 216
Top
 Profile  
 
Offline mitsun
 Post subject: Re: One space corner extension invasion question
Post #10 Posted: Fri Jun 20, 2014 1:12 pm 
Lives in gote

Posts: 553
Liked others: 61
Was liked: 250
Rank: AGA 5 dan
Click Here To Show Diagram Code
[go]$$B
$$ ----------------+
$$ . . . . . . . . |
$$ . . X O O . . . |
$$ . X . X O O a . |
$$ . . . X O X . . |
$$ . . . X X X . . |
$$ . . . . . . . . |[/go]

Suppose B manages to eliminate all outside weaknesses. Playing "a" would still be the wrong -- B has a better attack.
Top
 Profile  
 
Offline oca
 Post subject: Re: One space corner extension invasion question
Post #11 Posted: Fri Jun 20, 2014 2:54 pm 
Lives in gote
User avatar

Posts: 699
Location: Switzerland
Liked others: 485
Was liked: 166
Rank: DDK
KGS: aco
IGS: oca
OGS: oca
Something like that ? seki I think...

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

_________________
Converting the book Shape UP! by Charles Matthews/Seong-June Kim
to the gobook format. last updated april 2015 - Index of shapes, p.211 / 216
Top
 Profile  
 
Offline DrStraw
 Post subject: Re: One space corner extension invasion question
Post #12 Posted: Fri Jun 20, 2014 3:45 pm 
Oza

Posts: 2180
Location: ʍoquıɐɹ ǝɥʇ ɹǝʌo 'ǝɹǝɥʍǝɯos
Liked others: 237
Was liked: 662
Rank: AGA 5d
GD Posts: 4312
Online playing schedule: Every tenth February 29th from 20:00-20:01 (if time permits)
oca wrote:
Something like that ? seki I think...

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


9 at 10 creates a bulky 5, which is dead.

_________________
Still officially AGA 5d but I play so irregularly these days that I am probably only 3d or 4d over the board (but hopefully still 5d in terms of knowledge, theory and the ability to contribute).
Top
 Profile  
 
Offline cyclops
 Post subject: Re: One space corner extension invasion question
Post #13 Posted: Fri Jun 20, 2014 3:54 pm 
Lives in sente
User avatar

Posts: 801
Location: Amsterdam (NL)
Liked others: 353
Was liked: 107
Rank: KGS 7 kyu forever
GD Posts: 460
oca wrote:
Something like that ? seki I think...

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


:b9: is fine. It is not seki but w is dead. :w10: is worse than a pass! It looses sente, it costs 1 pt and you destroy about 4 liberties of your dead group. Making it much deader, so to speak.

edit: Ofcourse Joaz is right. :b9: is unnecessary most of the times.

_________________
I think I am so I think I am.


Last edited by cyclops on Fri Jun 20, 2014 4:08 pm, edited 4 times in total.
Top
 Profile  
 
Offline Joaz Banbeck
 Post subject: Re: One space corner extension invasion question
Post #14 Posted: Fri Jun 20, 2014 3:59 pm 
Judan
User avatar

Posts: 5546
Location: Banbeck Vale
Liked others: 1104
Was liked: 1457
Rank: 1D AGA
GD Posts: 1512
Kaya handle: Test
cyclops wrote:
...
:b9: is fine. It is not seki but w is dead.


:b9: is useful only if white has stones around M18 or M19 and is threatening to connect out, or if there is a liberties race - in which case T16 must be played, followed by T19, and the throwin at S19.

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

_________________
Help make L19 more organized. Make an index: https://lifein19x19.com/viewtopic.php?f=14&t=5207

This post by Joaz Banbeck was liked by: cyclops
Top
 Profile  
 
Offline cyclops
 Post subject: Re: One space corner extension invasion question
Post #15 Posted: Fri Jun 20, 2014 4:16 pm 
Lives in sente
User avatar

Posts: 801
Location: Amsterdam (NL)
Liked others: 353
Was liked: 107
Rank: KGS 7 kyu forever
GD Posts: 460
edit: off topic, deleted

_________________
I think I am so I think I am.


Last edited by cyclops on Sat Jun 21, 2014 5:26 pm, edited 1 time in total.
Top
 Profile  
 
Offline ez4u
 Post subject: Re: One space corner extension invasion question
Post #16 Posted: Fri Jun 20, 2014 6:01 pm 
Oza
User avatar

Posts: 2414
Location: Tokyo, Japan
Liked others: 2350
Was liked: 1332
Rank: Jp 6 dan
KGS: ez4u
Joaz Banbeck wrote:
...

:b9: is useful only if white has stones around M18 or M19 and is threatening to connect out, ...[snip]

Surely in that case :w8: will be played at 9, no? ;-)
Click Here To Show Diagram Code
[go]$$Bc
$$ --------------------+
$$ . . . . 9 6 . 7 5 . |
$$ . . O . X O O 0 1 8 |
$$ O O . X . X O O 2 4 |
$$ , . . . . X O X 3 . |
$$ . . . . . X X X . . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |[/go]

_________________
Dave Sigaty
"Short-lived are both the praiser and the praised, and rememberer and the remembered..."
- Marcus Aurelius; Meditations, VIII 21
Top
 Profile  
 
Offline Bill Spight
 Post subject: Re: One space corner extension invasion question
Post #17 Posted: Fri Jun 20, 2014 6:04 pm 
Honinbo

Posts: 10905
Liked others: 3651
Was liked: 3374
Dies in gote. ;)

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

Visualize whirled peas.

Everything with love. Stay safe.
Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  Page 1 of 1
  [ 17 posts ] 

Board index » Improve Your Game » Study Group

All times are UTC - 8 hours [ DST ]

Who is online

Users browsing this forum: No registered users and 1 guest

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group