Life In 19x19 :: Black to Kill

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Black to Kill http://www.lifein19x19.com/viewtopic.php?f=15&t=13039	Page 1 of 1

Author:	Joelnelsonb [ Wed Apr 06, 2016 8:44 pm ]
Post subject:	Black to Kill
I'm wondering how you would respond to the marked stone played below. I'm asking because this move wasn't listed under the solutions and I wonder if I'm missing something because this seems to work too and was the intuitive response for me. Click Here To Show Diagram Code `[go]$$W $$ $$ - . . . . . . . . . $$ - . X X , . . . . . $$ - . O O X X . X . . $$ - . . . O O X . . . $$ - . @ . . . . . . . $$ --------------------[/go]`

Author:	Solomon [ Wed Apr 06, 2016 8:57 pm ]
Post subject:	Re: Black to Kill
Click Here To Show Diagram Code `[go]$$B $$ $$ - . . . . . . . . . $$ - . X X , . . . . . $$ - 2 O O X X . X . . $$ - 1 . . O O X . . . $$ - . O . . 3 . . . . $$ --------------------[/go]`

Author:	EdLee [ Thu Apr 07, 2016 12:10 am ]
Post subject:
Solomon likes the placement first; how about the hane first... Click Here To Show Diagram Code `[go]$$B $$ \| . . . . . . . . . $$ \| . X . . . . . . . $$ \| . . . . . . . . . $$ \| . X X X . . . . . $$ \| . O O X X . X . . $$ \| 3 . . O O X . . . $$ \| . O 2 . 1 . . . . $$ --------------------[/go]` ( Maybe the placement is slightly better ? ) Click Here To Show Diagram Code `[go]$$B $$ \| . . . . . . . . . $$ \| . X . . . . . . . $$ \| . . . . . . . . . $$ \| . X X X . . . . . $$ \| . O O X X . X . . $$ \| 3 . 2 O O X . . . $$ \| . O . . 1 . . . . $$ --------------------[/go]` Click Here To Show Diagram Code `[go]$$B $$ \| . . . . . . . . . $$ \| . X . . . . . . . $$ \| . . . . . . . . . $$ \| . X X X . . . . . $$ \| . O O X X . X . . $$ \| 2 . 3 O O X . . . $$ \| . O . . 1 . . . . $$ --------------------[/go]` Click Here To Show Diagram Code `[go]$$B $$ \| . . . . . . . . . $$ \| . X . . . . . . . $$ \| . . . . . . . . . $$ \| . X X X . . . . . $$ \| . O O X X . X . . $$ \| 5 . 3 O O X . . . $$ \| . O 4 2 1 . . . . $$ --------------------[/go]` Click Here To Show Diagram Code `[go]$$B $$ \| . . . . . . . . . $$ \| . X . . . . . . . $$ \| . . . . . . . . . $$ \| . X X X . . . . . $$ \| . O O X X . X . . $$ \| . 2 . O O X . . . $$ \| . O . 3 1 . . . . $$ --------------------[/go]` To live: Click Here To Show Diagram Code `[go]$$W $$ \| . . . . . . . . . $$ \| . X . . . . . . . $$ \| . . . . . . . . . $$ \| . X X X . . . . . $$ \| . O O X X . X . . $$ \| . 1 . O O X . . . $$ \| . . . . . . . . . $$ --------------------[/go]`

Author:	Kirby [ Thu Apr 07, 2016 7:01 am ]
Post subject:	Re: Black to Kill
I think Ed's idea is basically working, and in general, reducing eyespace is a better first step than placement. In this case, however, I think the following variation can be "annoying", depending on what's nearby on the bottom side: Click Here To Show Diagram Code `[go]$$B $$ \| . . . . . . . . . $$ \| . X . . . . . . . $$ \| . . . . . . . . . $$ \| . X X X . . . . . $$ \| . O O X X . X . . $$ \| . . 3 O O X . . . $$ \| . O . 2 1 4 a . . $$ --------------------[/go]` Black cannot respond at 'a', so white has aji to play with to make something happen with nearby stones: Click Here To Show Diagram Code `[go]$$B $$ \| . . . . . . . . . $$ \| . X . . . . . . . $$ \| . . . . . . . . . $$ \| . X X X . . . . . $$ \| . O O X X 7 X . . $$ \| . 5 3 O O X 6 . 8 $$ \| . O . 2 1 4 . . . $$ --------------------[/go]` Depends on the rest of the board, but maybe something could happen. Or this: Click Here To Show Diagram Code `[go]$$B $$ \| . . . . . . . . . $$ \| . X . . . . . . . $$ \| . . . . . . . . . $$ \| . X X X . . 9 . . $$ \| . O O X X 8 X . . $$ \| . 5 3 O O C 6 7 0 $$ \| . O . 2 1 4 . . . $$ --------------------[/go]` Click Here To Show Diagram Code `[go]$$B $$ \| . . . . . . . . . $$ \| . X . . . . . . . $$ \| . . . . . . . . . $$ \| . X X X . 2 X . . $$ \| . O O X X O X . . $$ \| . X X O O . O X O $$ \| . O . O . O . 1 . $$ --------------------[/go]` I don't know if anything can happen if black is strong nearby, but there is aji. Compare with Solomon's solution, which I think has less aji here.

Author:	Uberdude [ Thu Apr 07, 2016 8:25 am ]
Post subject:	Re: Black to Kill
Kirby, the same aji exists in Solomon's variation of placement first, as white can also block the hane if it is played as move 3, black cuts, white captures, black plays 2-2 and then the same outside aji, but with white losing 3 rather than 2 stones on the left edge. FWIW placement first was my instinct too in this problem, probably because in related shapes such as killing the L shape when they attempt to live with that 2-1, you do need to do the placement before the hane, or else they play the 1-2 and live, but here the hane threatens to capture 2 stones not just reduce eyespace so either order works.

Author:	Kirby [ Thu Apr 07, 2016 9:59 am ]
Post subject:	Re: Black to Kill
Uberdude wrote: Kirby, the same aji exists in Solomon's variation of placement first, as white can also block the hane if it is played as move 3, black cuts, white captures, black plays 2-2 and then the same outside aji, but with white losing 3 rather than 2 stones on the left edge. FWIW placement first was my instinct too in this problem, probably because in related shapes such as killing the L shape when they attempt to live with that 2-1, you do need to do the placement before the hane, or else they play the 1-2 and live, but here the hane threatens to capture 2 stones not just reduce eyespace so either order works. Good point. I didn't think enough about the aji in Solomon's variation. I was trying to find a reason that hane was worse in this case, but maybe it's actually not.

Author:	Joelnelsonb [ Thu Apr 07, 2016 2:49 pm ]
Post subject:	Re: Black to Kill
On this one, I wonder if black can make good use of the marked stones. What do you think? Click Here To Show Diagram Code `[go]$$W Black to Move $$ - . . . . . . . . . . . . . . . $$ - . . . . . . . . . . . . . . . $$ - X . . . . . O . . O . . . . $$ - O X X X . . O X X O . . . . $$ - O O O , O . . O O , X X . . . $$ - . . O . . X . X X O . O X X . $$ - B . B O . . . . O O . O . . . $$ - . B . O . . . . . . . . . . . $$ --------------------[/go]`

Author:	Joelnelsonb [ Sat Apr 09, 2016 2:04 am ]
Post subject:	Re: Black to Kill
No takers, huh? I believe the marked stones are alive.

Author:	gamesorry [ Sat Apr 16, 2016 6:13 pm ]
Post subject:	Re: Black to Kill
I think 4-3 should be the first move. If white replies with 4-4: Click Here To Show Diagram Code `[go]$$B Black to Move $$ - . . . . . . . . . . . . . . . $$ - . . . . . . . . . . . . . . . $$ - X . . . . . O . . O . . . . $$ - O X X X . . O X X O . . . . $$ - O O O 2 O . . O O , X X . . . $$ - . . O 1 3 X . X X O . O X X . $$ - B . B O 6 7 . . O O . O . . . $$ - . B 9 O 5 4 8 . . . . . . . . $$ --------------------[/go]`

Author:	Joelnelsonb [ Sun Apr 17, 2016 8:07 am ]
Post subject:	Re: Black to Kill
gamesorry wrote: I think 4-3 should be the first move. If white replies with 4-4: Click Here To Show Diagram Code `[go]$$B Black to Move $$ - . . . . . . . . . . . . . . . $$ - . . . . . . . . . . . . . . . $$ - X . . . . . O . . O . . . . $$ - O X X X . . O X X O . . . . $$ - O O O 2 O . . O O , X X . . . $$ - . . O 1 3 X . X X O . O X X . $$ - B . B O 6 7 . . O O . O . . . $$ - . B 9 O 5 4 8 . . . . . . . . $$ --------------------[/go]` There is an essential move that must be made previously.

Author:	Schachus [ Mon Apr 18, 2016 2:54 am ]
Post subject:	Re: Black to Kill
Why? Gamesorrys sequence seems to work for Black.Could White improve somewhere?

Author:	Joelnelsonb [ Wed Apr 20, 2016 9:54 am ]
Post subject:	Re: Black to Kill
Black 9 does not create a living shape. You must create an atari somehow in order to force the eye shape.

Author:	jeromie [ Wed Apr 20, 2016 10:19 am ]
Post subject:	Re: Black to Kill
Joelnelsonb wrote: Black 9 does not create a living shape. You must create an atari somehow in order to force the eye shape. Sure it does. There is one eye in the corner and one after black capture the three white stones in the 6 group. They can't escape. If white connects with 10 black plays on the first line and captures the whole group.

Author:	gamesorry [ Thu Apr 21, 2016 8:23 pm ]
Post subject:	Re: Black to Kill
Joelnelsonb wrote: There is an essential move that must be made previously. Click Here To Show Diagram Code `[go]$$B Oh, perhaps white could resist at 2-2 $$ - . . . . . . . . . . . . . . . $$ - . . . . . . . . . . . . . . . $$ - X . . . . . O . . O . . . . $$ - O X X X . . O X X O . . . . $$ - O O O 2 O . . O O , X X . . . $$ - . 5 O 1 3 X . X X O . O X X . $$ - B 4 B O . . . . O O . O . . . $$ - . B 6 O . . . . . . . . . . . $$ --------------------[/go]` Click Here To Show Diagram Code `[go]$$B But the atari here doesn't seem to help much? (especially in saving the corner stones) $$ - . . . . . . . . . . . . . . . $$ - . . . . . . . . . . . . . . . $$ - X . . . . . O . . O . . . . $$ - O X X X . . O X X O . . . . $$ - O O O 4 O . 1 O O 2 X X . . . $$ - . 7 O 3 5 X . X X O . O X X . $$ - B 6 B O . . . . O O . O . . . $$ - . B 8 O . . . . . . . . . . . $$ --------------------[/go]` Click Here To Show Diagram Code `[go]$$B Black might sacrifice the left part of the group and escape though $$ - . . . . . . . . . . . . . . . $$ - . . . . . . . . . . . . . . . $$ - X . . . 6 7 O . . O . . . . $$ - O X X X 4 5 O X X O . . . . $$ - O O O O O 3 X O O O X X . . . $$ - 2 X O X X X . X X O . O X X . $$ - B 1 B O . . . . O O . O . . . $$ - . B O O . . . . . . . . . . . $$ --------------------[/go]` Click Here To Show Diagram Code `[go]$$B It's also possible to atari from the other side $$ - . . . . . . . . . . . . . . . $$ - . . . . . . . . . . . . . . . $$ - X . . . . . O . . O . . . . $$ - O X X X . . O X X O . . . . $$ - O O O 4 O . 2 O O 1 X X . . . $$ - . 7 O 3 5 X . X X O . O X X . $$ - B 6 B O . . . . O O . O . . . $$ - . B 8 O . . . . . . . . . . . $$ --------------------[/go]` Click Here To Show Diagram Code `[go]$$B (Cont'd) (Assume black doesn't have advantage on ko) $$ - . . . . . . . . . . . . . . . $$ - . . . . . . . . . . . . . . . $$ - X . . . . . O . . O . . . . $$ - O X X X . . O X X O . . . . $$ - O O O O O . O O O X X X . . . $$ - . X O X X X . X X O 5 O X X . $$ - X 2 4 O 1 . . 3 O O 6 O . . . $$ - . X O O . . . . . . . . . . . $$ --------------------[/go]` Click Here To Show Diagram Code `[go]$$B (Cont'd) Doesn't look right for black $$ - . . . . . . . . . . . . . . . $$ - . . . . . . . . . . . . . . . $$ - X . . . . . O . . O . . . . $$ - O X X X . . O X X O . . . . $$ - O O O O O . O O O X X X . . . $$ - . X O X X X 2 X X O X O X X . $$ - X O O O X . 3 X O O O O 1 . . $$ - . X O O . 4 . . . . . . . . . $$ --------------------[/go]` Joelnelsonb wrote: Black 9 does not create a living shape. You must create an atari somehow in order to force the eye shape. It seems that after Black 9 white can't kill?

Author:	Joelnelsonb [ Fri Apr 22, 2016 6:50 am ]
Post subject:	Re: Black to Kill
White has to block at four after the atari at black 1. I dont think I would play this sequence in a game though (depending on the overall position) given that the corner seems too small to give up the black influenced down the left side. Click Here To Show Diagram Code `[go]$$B $$ - . . . . . . . . . . . . . . . $$ - . . . . . . . . . . . . . . . $$ - X 6 . . . . O . . O . . . . $$ - O X X X . . O X X O . . . . $$ - O O O 5 O . 1 O O 2 X X . . . $$ - . 9 O 3 4 X . X X O . O X X . $$ - B . B O . 8 . . O O . O . . . $$ - . B 7 O . . . . . . . . . . . $$ --------------------[/go]`

Author:	Uberdude [ Fri Apr 22, 2016 10:01 am ]
Post subject:	Re: Black to Kill
Joelnelsonb wrote: Black 9 does not create a living shape. Can you show how to kill?

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