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How to respond in this case?

Posted: Thu Nov 13, 2014 12:30 am
by gostudent
In the following sequence, B5 cannot tenuki, because there is a sequence after W6 B7 that will make white very thick.
Click Here To Show Diagram Code
[go]$$c
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . 2 3 . . . . |
$$ | . . . 5 . . . . . , . . . 4 . 1 . . . |
$$ | . . . . . . . . . . . . . . . 6 7 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

However, if B7 plays this way, it seems to lead to a fight that white is not easy to win:
Click Here To Show Diagram Code
[go]$$c
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . 2 3 . . . . |
$$ | . . . 5 . . . . . , . . . 4 7 1 . . . |
$$ | . . . . . . . . . . . . . 9 8 6 . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
I have tried different sequences, and it seems that the black corner group cannot be killed. One example sequence is
Click Here To Show Diagram Code
[go]$$W
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . a . . . . |
$$ | . . . . . . . . . . . . . 3 2 5 7 0 c |
$$ | . . . . . . . . . . . . . O X 6 4 8 b |
$$ | . . . X . . . . . , . . . O X X 1 9 . |
$$ | . . . . . . . . . . . . . X O O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
White plays at a cannot save the two white stone because of snapback, and white playing at b or c also doesn't seem to work either.

Is there any sequence to kill black that I miss? If black is alive, how should white respond after the cut?

Thanks.

Posted: Thu Nov 13, 2014 1:15 am
by EdLee
How do you feel about this ?
Click Here To Show Diagram Code
[go]$$W
$$ -----------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . 2 . . . . |
$$ | . . . . . . . . . . . . . O X . 3 . . |
$$ | . . . X . . . . . , . . . O X X 1 . . |
$$ | . . . . . . . . . . . . . X O O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |[/go]
W gets a lot of cash, and B has a heavy group.

Re: How to respond in this case?

Posted: Thu Nov 13, 2014 1:19 am
by schawipp
How about a move like :w2: which makes miai to connect to either side. If b tries hard to threaten one of the split w groups something like the following could happen (just dreaming ;-) I cannot foresee all possible variations here of course...).
Click Here To Show Diagram Code
[go]$$c :w10: captures at a
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . a . 2 . . |
$$ | . . . . . . . . . . . . . O X . . . . |
$$ | . . . X . . . . . , . . . O X X 8 . . |
$$ | . . . . . . . . . . . . . 1 O O 3 9 . |
$$ | . . . . . . . . . . . . . . 6 5 4 . . |
$$ | . . . . . . . . . . . . . . . 7 . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
Update: I have not tested :w2: thoroughly and EdLee's variation is probably good enough.

Update II: Another possible variation after :w2: which looks quite satisfactory:
Click Here To Show Diagram Code
[go]$$c :w10: jumps at a
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . 8 . . . . . |
$$ | . . . . . . . . . . . . 6 5 4 7 2 . . |
$$ | . . . . . . . . . . . . . O X . . . . |
$$ | . . . X . . . . . , . . . O X X 3 . . |
$$ | . . . . . . . . . . . . . 1 O O 9 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . a . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Posted: Thu Nov 13, 2014 1:22 am
by EdLee
gostudent wrote:
Click Here To Show Diagram Code
[go]$$W
$$ -----------------------------------------
$$ | . . . . . . . . . . . . . . a . . . . |
$$ | . . . . . . . . . . . . . 3 2 5 7 0 . |
$$ | . . . . . . . . . . . . . O X 6 4 8 . |
$$ | . . . X . . . . . , . . . O X X 1 9 . |
$$ | . . . . . . . . . . . . . X O O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |[/go]
White plays at a cannot save the two white stone because of snapback
No. Read again and find the correct reason W(a) fails.

Re: How to respond in this case?

Posted: Thu Nov 13, 2014 3:43 am
by Uberdude
schawipp wrote:How about a move like :w2: which makes miai to connect to either side. If b tries hard to threaten one of the split w groups something like the following could happen (just dreaming ;-) I cannot foresee all possible variations here of course...).
Whilst I applaud your creativity, this is bonkers. gostudent's hane is a much better feeling (take a liberty of black's empty triangle, make your stones stronger, reduce eyespace). Black just stops connection on one side, white thinly connects the other (still problem at a/b later) and then cuts and white can't keep it all together.
Click Here To Show Diagram Code
[go]$$c
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . b 6 a 2 . . |
$$ | . . . . . . . . . . . . . O X . . . . |
$$ | . . . X . . . . . , . . . O X X 5 . . |
$$ | . . . . . . . . . . . . . 1 O O 3 . . |
$$ | . . . . . . . . . . . . . . . 7 4 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
schawipp wrote:Update: I have not tested thoroughly and EdLee's variation is probably good enough.
Not just good enough, but better.

Re:

Posted: Thu Nov 13, 2014 11:51 pm
by gostudent
EdLee wrote:
gostudent wrote:
Click Here To Show Diagram Code
[go]$$W
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . a . . . . |
$$ | . . . . . . . . . . . . . 3 2 5 7 0 . |
$$ | . . . . . . . . . . . . . O X 6 4 8 . |
$$ | . . . X . . . . . , . . . O X X 1 9 . |
$$ | . . . . . . . . . . . . . X O O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |[/go]
White plays at a cannot save the two white stone because of snapback
No. Read again and find the correct reason W(a) fails.
I am thinking about the following sequence, and white cannot connect at 2 because black can simply take at a. And B6 is at 2 to capture the 3 white stones. Then b and the key point of the three stones would be miai.
Click Here To Show Diagram Code
[go]$$W
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . a 1 2 3 4 . |
$$ | . . . . . . . . . . . . . O X O O X b |
$$ | . . . . . . . . . . . . . O X X X X 5 |
$$ | . . . X . . . . . , . . . O X X O O . |
$$ | . . . . . . . . . . . . . X O O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Re:

Posted: Fri Nov 14, 2014 12:02 am
by gostudent
EdLee wrote:How do you feel about this ?
Click Here To Show Diagram Code
[go]$$W
$$ -----------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . 2 . . . . |
$$ | . . . . . . . . . . . . . O X . 3 . . |
$$ | . . . X . . . . . , . . . O X X 1 . . |
$$ | . . . . . . . . . . . . . X O O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |[/go]
W gets a lot of cash, and B has a heavy group.
Thanks. It is a fairly good result for white.

A lesson for me here is that, after W1 and B2, the 3-3 point becomes so vital that white has to take it -- letting black play there would almost surely lead to black life. So I have to allow black to escape. Since the running group is heavy, even though I might not be able to kill it, I should get plenty in return. On the other hand, if I insist on surrounding, after black plays at 3-3 and makes life, I would be in a very bad situation with two weak groups.

Posted: Fri Nov 14, 2014 12:48 am
by EdLee
gostudent wrote:I am thinking about the following sequence...
Click Here To Show Diagram Code
[go]$$W
$$ -----------------------------------------
$$ | . . . . . . . . . . . . . a 1 2 3 4 . |
$$ | . . . . . . . . . . . . . O X O O X b |
$$ | . . . . . . . . . . . . . O X X X X 5 |
$$ | . . . X . . . . . , . . . O X X O O . |
$$ | . . . . . . . . . . . . . X O O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ -----------------------------------------[/go]
Hi GoStudent,

Yes, we knew what you were thinking. :)
Please read again. You're still missing something very basic. :)

Posted: Fri Nov 14, 2014 12:58 am
by EdLee
schawipp wrote:Another possible variation...
Click Here To Show Diagram Code
[go]$$
$$ -----------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . y 5 O x 2 . . |
$$ | . . . . . . . . . . . . . O X . . . . |
$$ | . . . X . . . . . , . . . O X X X . . |
$$ | . . . . . . . . . . . . . X O O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |[/go]
( Diagram edited for clarity. )

Hi schawipp,

Putting aside :w2: (please see Uberdude's comments about it),
the :b5: above is a common mistake.

If B wants to wedge :black: (x), then B should play it directly,
without the exchange [ :b5: - :white: (y) ] which gives W a very nice ponnuki.
If :black: (x) directly, W cannot get the nice ponnuki shape in your variation.

Re: How to respond in this case?

Posted: Fri Nov 14, 2014 3:02 am
by Uberdude
gostudent wrote:A lesson for me here is that, after W1 and B2, the 3-3 point becomes so vital that white has to take it -- letting black play there would almost surely lead to black life. So I have to allow black to escape. Since the running group is heavy, even though I might not be able to kill it, I should get plenty in return. On the other hand, if I insist on surrounding, after black plays at 3-3 and makes life, I would be in a very bad situation with two weak groups.
I wouldn't say very bad, like this is also playable for white. You are cut, but neither group is particularly weak.
Click Here To Show Diagram Code
[go]$$W
$$ -----------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . 3 2 . . . . |
$$ | . . . . . . . . . . 7 . . O X . 4 6 . |
$$ | . . . X . . . . . , . . . O X X 1 . . |
$$ | . . . . . . . . . . . . . X O O 5 . . |
$$ | . . . . . . . . . . . . . 8 . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . 9 . . . |[/go]
In fact when you let black escape I want to press black down at 5 (rather than backing off at 8 which might be good enough but I want to play as severely as possible) but then it gets rather complicated, I didn't finish reading who is overplaying here.
Click Here To Show Diagram Code
[go]$$W
$$ -----------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . 4 . 2 . . . . |
$$ | . . . . . . . . . . . 5 6 O X . 3 . . |
$$ | . . . X . . . . . , . 8 7 O X X 1 . . |
$$ | . . . . . . . . . . . . . X O O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |[/go]
If black turns white is plenty happy with the jump:
Click Here To Show Diagram Code
[go]$$W
$$ -----------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . 6 4 2 . . . . |
$$ | . . . . . . . . . . . 5 . O X . 3 . . |
$$ | . . . X . . . . . , . . . O X X 1 . . |
$$ | . . . . . . . . . . . 7 . X O O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |[/go]

Re: How to respond in this case?

Posted: Fri Nov 14, 2014 3:23 am
by schawipp
Thanks EdLee and Uberdude for the corrections! I have not yet encountered black's original response (the empty triangle) but if that happens now, I should know what to do! ;-)

Re: How to respond in this case?

Posted: Fri Nov 14, 2014 3:32 am
by Uberdude
Btw, if you hane first the empty triangle is actually a strong move, better than crawling at a (Of course you usually don't want to kick and then tenuki, but maybe the tenuki was actually a pincer around b).
Click Here To Show Diagram Code
[go]$$c
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . O X . . . . |
$$ | . . . X . . . . . , b . . O 3 X 5 . . |
$$ | . . . . . . . . . . . . . 4 . O 1 . . |
$$ | . . . . . . . . . . . . . . . 2 a . . |
$$ | . . . . . . . . . . . . 6 . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Re:

Posted: Sat Nov 15, 2014 10:31 pm
by gostudent
EdLee wrote:
gostudent wrote:I am thinking about the following sequence...
Click Here To Show Diagram Code
[go]$$W
$$ -----------------------------------------
$$ | . . . . . . . . . . . . . a 1 2 3 4 . |
$$ | . . . . . . . . . . . . . O X O O X b |
$$ | . . . . . . . . . . . . . O X X X X 5 |
$$ | . . . X . . . . . , . . . O X X O O . |
$$ | . . . . . . . . . . . . . X O O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ -----------------------------------------[/go]
Hi GoStudent,

Yes, we knew what you were thinking. :)
Please read again. You're still missing something very basic. :)
Do you mean the following sequence?
Click Here To Show Diagram Code
[go]$$W
$$ -----------------------------------------
$$ | . . . . . . . . . . . . . . 1 2 4 . . |
$$ | . . . . . . . . . . . . . O X O O X 5 |
$$ | . . . . . . . . . . . . . O X X X X 3 |
$$ | . . . X . . . . . , . . . O X X O O . |
$$ | . . . . . . . . . . . . . X O O 6 7 . |
$$ | . . . . . . . . . . . . . . . . 8 . . |
$$ -----------------------------------------[/go]
and then either
Click Here To Show Diagram Code
[go]$$W
$$ -----------------------------------------
$$ | . . . . . . . . . . . . . . O X X . . |
$$ | . . . . . . . . . . . . . O X . . X O |
$$ | . . . . . . . . . . . . . O X X X X O |
$$ | . . . X . . . . . , . . . O X X O O . |
$$ | . . . . . . . . . . . . . X O O X O . |
$$ | . . . . . . . . . . . . . . 2 . X 1 . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ -----------------------------------------[/go]
or
Click Here To Show Diagram Code
[go]$$W
$$ -----------------------------------------
$$ | . . . . . . . . . . . . . . O X X 3 . |
$$ | . . . . . . . . . . . . . O X . . X O |
$$ | . . . . . . . . . . . . . O X X X X O |
$$ | . . . X . . . . . , . . . O X X O O 4 |
$$ | . . . . . . . . . . . . . X O O X O 5 |
$$ | . . . . . . . . . . . . . . . . X 2 6 |
$$ | . . . . . . . . . . . . . . . 1 . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ -----------------------------------------[/go]

Posted: Sun Nov 16, 2014 12:48 am
by EdLee
gostudent wrote:Do you mean the following sequence?
Click Here To Show Diagram Code
[go]$$W
$$ -----------------------------------------
$$ | . . . . . . . . . . . . . . 1 2 . . . |
$$ | . . . . . . . . . . . . . O X O O X . |
$$ | . . . . . . . . . . . . . O X X X X . |
$$ | . . . X . . . . . , . . . O X X O O . |
$$ | . . . . . . . . . . . . . X O O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |[/go]
No. No throw-in. No snapback.

Re:

Posted: Sun Nov 16, 2014 7:11 am
by oca
EdLee wrote:
gostudent wrote:I am thinking about the following sequence...
Click Here To Show Diagram Code
[go]$$W
$$ -----------------------------------------
$$ | . . . . . . . . . . . . . a 1 2 3 4 . |
$$ | . . . . . . . . . . . . . O X O O X b |
$$ | . . . . . . . . . . . . . O X X X X 5 |
$$ | . . . X . . . . . , . . . O X X O O . |
$$ | . . . . . . . . . . . . . X O O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ -----------------------------------------[/go]
Hi GoStudent,

Yes, we knew what you were thinking. :)
Please read again. You're still missing something very basic. :)
Oups... I'm missing that too :oops: