Life In 19x19 :: How to respond in this case?

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How to respond in this case? http://www.lifein19x19.com/viewtopic.php?f=11&t=11063	Page 1 of 2

Author: gostudent [ Thu Nov 13, 2014 12:30 am ]

Post subject: How to respond in this case?

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.

Author:	EdLee [ Thu Nov 13, 2014 1:15 am ]
Post subject:
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.

Author: schawipp [ Thu Nov 13, 2014 1:19 am ]

Post subject: Re: How to respond in this case?

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]$$c captures at a $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . 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]$$c jumps at a $$ --------------------------------------- $$ | . . . . . . . . . . . . . 8 . . . . . | $$ | . . . . . . . . . . . . 6 5 4 7 2 . . | $$ | . . . . . . . . . . . . . O X . . . . | $$ | . . . X . . . . . , . . . O X X 3 . . | $$ | . . . . . . . . . . . . . 1 O O 9 . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . a . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Author:	EdLee [ Thu Nov 13, 2014 1:22 am ]
Post subject:
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.

Author:	Uberdude [ Thu Nov 13, 2014 3:43 am ]
Post subject:	Re: How to respond in this case?
schawipp wrote: How about a move like 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.

Author:	gostudent [ Thu Nov 13, 2014 11:51 pm ]
Post subject:	Re:
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]

Author:	gostudent [ Fri Nov 14, 2014 12:02 am ]
Post subject:	Re:
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.

Author:	EdLee [ Fri Nov 14, 2014 12:48 am ]
Post subject:
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.

Author:	EdLee [ Fri Nov 14, 2014 12:58 am ]
Post subject:
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 (please see Uberdude's comments about it), the above is a common mistake. If B wants to wedge (x), then B should play it directly, without the exchange [ - (y) ] which gives W a very nice ponnuki. If (x) directly, W cannot get the nice ponnuki shape in your variation.

Author: Uberdude [ Fri Nov 14, 2014 3:02 am ]

Post subject: Re: How to respond in this case?

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]

Author:	schawipp [ Fri Nov 14, 2014 3:23 am ]
Post subject:	Re: How to respond in this case?
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!

Author:	Uberdude [ Fri Nov 14, 2014 3:32 am ]
Post subject:	Re: How to respond in this case?
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]

Author: gostudent [ Sat Nov 15, 2014 10:31 pm ]

Post subject: Re:

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]

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]

Author:	EdLee [ Sun Nov 16, 2014 12:48 am ]
Post subject:
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.

Author:	oca [ Sun Nov 16, 2014 7:11 am ]
Post subject:	Re:
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

Author:	illluck [ Sun Nov 16, 2014 7:46 am ]
Post subject:	Re:
EdLee wrote: No. No throw-in. No snapback. Does Ed mean the other atari, or does he mean this cut below? The cut is better, but seems like Ed is hinting at the other atari. Click Here To Show Diagram Code `[go]$$W $$ ----------------------------------------- $$ \| . . . . . . . . . . . . . . 1 . . . . \| $$ \| . . . . . . . . . . . . . O X O O X . \| $$ \| . . . . . . . . . . . . . O X X X X . \| $$ \| . . . X . . . . . , . . . O X X O O . \| $$ \| . . . . . . . . . . . . . X O O 2 . . \| $$ \| . . . . . . . . . . . . . . . . . . . \|[/go]`

Author: EdLee [ Sun Nov 16, 2014 8:43 pm ]

Post subject:

Hi illluck,

Hi GoStudent, oca:
Technical issue about the diagrams:
This one shows an "open" board toward the center:

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

This one is a closed 19x6 board:

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

Big difference.

If you want to see the solution, you can open the above hidden text.

Author:	oca [ Sun Nov 16, 2014 11:17 pm ]
Post subject:	Re: How to respond in this case?
Thank you Edlee, I got it... Seeing throw in everwhere even when there is a simple solution seems to be a new bad habit I developped...

Author:	EdLee [ Mon Nov 17, 2014 12:38 am ]
Post subject:
Hi oca, you're welcome. ( We ignore the rest of the board and other life-and-death considerations. ) If atari directly, after connects, then later B can take at (a), or W can connect at (a): Click Here To Show Diagram Code `[go]$$W Variation A $$ --------------------- $$ . . . . 3 1 a 2 . . \| $$ . . . . O X O O X . \| $$ . . . . O X X X X . \| $$ . . . . . . . . . . \|[/go]` However, if throws in first, after still connects as above, the situation is different -- later, W can capture at (b). The points are different from variation A. Click Here To Show Diagram Code `[go]$$W Variation B $$ --------------------- $$ . . . . 3 1 2 b . . \| $$ . . . . O X O O X . \| $$ . . . . O X X X X . \| $$ . . . . . . . . . . \|[/go]`

Author:	oca [ Mon Nov 17, 2014 4:37 am ]
Post subject:	Re: How to respond in this case?
EdLee wrote: Hi oca, you're welcome. ( We ignore the rest of the board and other life-and-death considerations. ) If atari directly, after connects, then later B can take at (a), or W can connect at (a): Click Here To Show Diagram Code `[go]$$W Variation A $$ --------------------- $$ . . . . 3 1 a 2 . . \| $$ . . . . O X O O X . \| $$ . . . . O X X X X . \| $$ . . . . . . . . . . \|[/go]` However, if throws in first, after still connects as above, the situation is different -- later, W can capture at (b). The points are different from variation A. Click Here To Show Diagram Code `[go]$$W Variation B $$ --------------------- $$ . . . . 3 1 2 b . . \| $$ . . . . O X O O X . \| $$ . . . . O X X X X . \| $$ . . . . . . . . . . \|[/go]` I'm currently reading a book about Yose. For now I have only read 1/4 of the book, but that allready changed my undertsanding of sente... For example, till now, was sente for me... but, it's not. or at least not necessarily (still ignoring life-and-death considerations here)... so I think black has to count the value of capturing the two stones, and see if there is something bigger somwhere else... Let's try to count the points... (warning, That's the first time I'm doing this, that may be all wrong...) Variation A Click Here To Show Diagram Code `[go]$$B Variation A, black yose $$ --------------------- $$ . . . . O O 1 X S . \| $$ . . . . O X @ @ X . \| $$ . . . . O X X X X . \| $$ . . . . . . . . . . \|[/go]` black : 5 pts (2 catures + 3 pts local territory, in gote white : 0 pts so I would say black +5 Click Here To Show Diagram Code `[go]$$W Variation A, white yose () $$ --------------------- $$ . . . . O O 1 X a . \| $$ . . . . O X O O X . \| $$ . . . . O X X X X . \| $$ . . . . . . . . . . \|[/go]` black : 0 white : 2 (2 is my approximation for white's privilege at a) so it's black -2 in this case Which means the global value of yose of vvariation A is 3 points in gote... Before I will do variation B, can someone tell if I'm full wrong in my calcultation or if I'm somehow correct ?

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