Life In 19x19
http://www.lifein19x19.com/

Capture go problem
http://www.lifein19x19.com/viewtopic.php?f=15&t=4003		 Page 1 of 2
Author:  Bill Spight [ Thu Jun 09, 2011 7:39 am ]
Post subject:  Capture go problem
Click Here To Show Diagram Code
[go]$$ Black to play
$$ -----------
$$ | X . . . . |
$$ | X X X X X |
$$ | X O X O X |
$$ | O O O O O |
$$ | O . . O . |
$$ -----------[/go]


Easy, but, I think, instructive. :)

Edit:

Capture go.

Passing is not allowed. The first player to capture a stone wins.
Author:  Kirby [ Thu Jun 09, 2011 7:56 am ]
Post subject:  Re: Capture go problem
Pass? I don't really get it...
Author:  Li Kao [ Thu Jun 09, 2011 8:02 am ]
Post subject:  Re: Capture go problem
@Kirby
I think you can't pass in capture go. So the point of this problem is to force your opponent to fill his eyes first. But I can't find a good ruleset for capture go atm.
Image
Author:  daniel_the_smith [ Thu Jun 09, 2011 8:04 am ]
Post subject:  Re: Capture go problem
Click Here To Show Diagram Code
[go]$$B Black to play
$$ -----------
$$ | X . 1 3 . |
$$ | X X X X X |
$$ | X O X O X |
$$ | O O O O O |
$$ | O . 2 O . |
$$ -----------[/go]


...and white is forced to play self atari?

Maybe Bill is trying to demonstrate how capture go could evolve into regular go?

Or maybe I'm missing the point completely...
Author:  Koroviev [ Thu Jun 09, 2011 8:06 am ]
Post subject:  Re: Capture go problem
Could you explain rules, Bill? I find various different ones online.
Author:  Kirby [ Thu Jun 09, 2011 8:06 am ]
Post subject:  Re: Capture go problem
Li Kao wrote:
@Kirby
I think you can't pass in capture go. So the point of this problem is to force your opponent to fill his eyes first. But I can't find a good ruleset for capture go atm.


Ah, thanks, Li Kao. I wasn't thinking of "capture go", the game. For some reason, I was assuming that this was "regular go".
Author:  Bill Spight [ Thu Jun 09, 2011 10:02 am ]
Post subject:  Re: Capture go problem
daniel_the_smith wrote:
Click Here To Show Diagram Code
[go]$$B Black to play
$$ -----------
$$ | X . 1 3 . |
$$ | X X X X X |
$$ | X O X O X |
$$ | O O O O O |
$$ | O . 2 O . |
$$ -----------[/go]


...and white is forced to play self atari?

Maybe Bill is trying to demonstrate how capture go could evolve into regular go?

Or maybe I'm missing the point completely...


Right answer. But you are missing the point. Consider wrong answers. :)
Author:  Bill Spight [ Thu Jun 09, 2011 10:04 am ]
Post subject:  Re: Capture go problem
Koroviev wrote:
Could you explain rules, Bill? I find various different ones online.


Sorry. I have edited the problem to show where the rules differ from regular go.
Author:  daal [ Thu Jun 09, 2011 10:28 am ]
Post subject:  Re: Capture go problem
black needs to make two eyes to win?
Author:  Li Kao [ Thu Jun 09, 2011 10:28 am ]
Post subject:  Re: Capture go problem
If you just need to capture a single stone the problem looks pretty pointless.
There are three first moves.
Click Here To Show Diagram Code
[go]$$ The three moves
$$ -----------
$$ | X b c c b |
$$ | X X X X X |
$$ | X O X O X |
$$ | O O O O O |
$$ | O a a O . |
$$ -----------[/go]


a) is selfatari
b) leads to a 3 point eye which once white jumps into its middle forces a self atari
Click Here To Show Diagram Code
[go]$$ Fail - now all allowed moves are self atari
$$ -----------
$$ | X 1 . 2 . |
$$ | X X X X X |
$$ | X O X O X |
$$ | O O O O O |
$$ | O . . O . |
$$ -----------[/go]

c) daniel's sequence which works. White can't deviate at move 2 since all other moves are self atari.

I really don't see your point.
Author:  Bill Spight [ Thu Jun 09, 2011 11:29 am ]
Post subject:  Re: Capture go problem
Li Kao wrote:
If you just need to capture a single stone the problem looks pretty pointless.
There are three first moves.
Click Here To Show Diagram Code
[go]$$ The three moves
$$ -----------
$$ | X b c c b |
$$ | X X X X X |
$$ | X O X O X |
$$ | O O O O O |
$$ | O a a O . |
$$ -----------[/go]


a) is selfatari
b) leads to a 3 point eye which once white jumps into its middle forces a self atari
Click Here To Show Diagram Code
[go]$$ Fail - now all allowed moves are self atari
$$ -----------
$$ | X 1 . 2 . |
$$ | X X X X X |
$$ | X O X O X |
$$ | O O O O O |
$$ | O . . O . |
$$ -----------[/go]

c) daniel's sequence which works. White can't deviate at move 2 since all other moves are self atari.

I really don't see your point.


The point is the seki in variation b). Even though you don't need two eyes to live in capture go, you may need two eyes to avoid seki. :)
Author:  Li Kao [ Thu Jun 09, 2011 12:27 pm ]
Post subject:  Re: Capture go problem
Bill Spight wrote:
Li Kao wrote:
b) leads to a 3 point eye which once white jumps into its middle forces a self atari
Click Here To Show Diagram Code
[go]$$ Fail - now all allowed moves are self atari
$$ -----------
$$ | X 1 . 2 . |
$$ | X X X X X |
$$ | X O X O X |
$$ | O O O O O |
$$ | O . . O . |
$$ -----------[/go]


The point is the seki in variation b). Even though you don't need two eyes to live in capture go, you may need two eyes to avoid seki. :)

How is that a seki? It's black to move. He may not pass. So he will need to play a self-atari and lose one white's next turn.
Author:  palapiku [ Thu Jun 09, 2011 1:27 pm ]
Post subject:  Re: Capture go problem
The term "seki" only makes sense when passing is allowed. So does the word "alive", for that matter.
Author:  Shaddy [ Thu Jun 09, 2011 5:00 pm ]
Post subject:  Re: Capture go problem
I think seki makes sense without passes. It means that the first player to play locally gets a poor result, somehow. In this case there's nowhere else to play, so black just loses.
Author:  Bill Spight [ Thu Jun 09, 2011 5:08 pm ]
Post subject:  Re: Capture go problem
Li Kao wrote:
Bill Spight wrote:
Li Kao wrote:
b) leads to a 3 point eye which once white jumps into its middle forces a self atari
Click Here To Show Diagram Code
[go]$$ Fail - now all allowed moves are self atari
$$ -----------
$$ | X 1 . 2 . |
$$ | X X X X X |
$$ | X O X O X |
$$ | O O O O O |
$$ | O . . O . |
$$ -----------[/go]


The point is the seki in variation b). Even though you don't need two eyes to live in capture go, you may need two eyes to avoid seki. :)

How is that a seki? It's black to move. He may not pass. So he will need to play a self-atari and lose one white's next turn.


The top region is seki. Neither side may approach the other. :)
Author:  mitsun [ Thu Jun 09, 2011 6:18 pm ]
Post subject:  Re: Capture go problem
I agree that seki is a misleading concept in capture go. In chess and maybe other games the German term "zugzwang" is used for this situation.

By the way, what happens if both sides make two one-point eyes and fill all dame, so that there are no legal moves left? Is the game a draw, or does the next player lose?
Author:  Bill Spight [ Thu Jun 09, 2011 6:40 pm ]
Post subject:  Re: Capture go problem
mitsun wrote:
I agree that seki is a misleading concept in capture go. In chess and maybe other games the German term "zugzwang" is used for this situation.


Well, seki can be used as a ko threat in regular go, but there are no kos in capture go (capture-1, anyway). Otherwise, in a regular seki the player to move will suffer a loss. (There are other standoff situations in regular go that are not seki, such as three-points-without-capturing.)

Quote:
By the way, what happens if both sides make two one-point eyes and fill all dame, so that there are no legal moves left? Is the game a draw, or does the next player lose?


It is legal to fill your own eye. But yes, there are possible positions in capture go where a player may not have a move. I would call such a position a loss for that player.
Author:  RobertJasiek [ Thu Jun 09, 2011 11:00 pm ]
Post subject:  Re: Capture go problem
palapiku wrote:
The term "seki" only makes sense when passing is allowed.


As Tang Rules show, seki makes sense also without passes.
viewtopic.php?f=45&t=4005
Author:  ChradH [ Fri Jun 10, 2011 12:15 am ]
Post subject:  Re: Capture go problem
RobertJasiek wrote:
palapiku wrote:
The term "seki" only makes sense when passing is allowed.


As Tang Rules show, seki makes sense also without passes.
http://www.lifein19x19.com/forum/viewto ... =45&t=4005

Yes, but in capture go there is "zugzwang", you can not simply end the game by agreement. Or am I missing something? :-?
Author:  Bill Spight [ Fri Jun 10, 2011 10:58 am ]
Post subject:  Re: Capture go problem
ChradH wrote:
Yes, but in capture go there is "zugzwang", you can not simply end the game by agreement. Or am I missing something? :-?


Actually, ending the game by agreement (instead of ending the game by passing) is an emergent feature of no pass go, as is the concept of territory. :)
Page 1 of 2 All times are UTC - 8 hours [ DST ]
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group
http://www.phpbb.com/