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Weirdish position
http://www.lifein19x19.com/viewtopic.php?f=45&t=3391
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Author:  fwiffo [ Tue Mar 08, 2011 6:49 pm ]
Post subject:  Weirdish position

A position analogous to this appeared in one of my games recently.

Click Here To Show Diagram Code
[go]$$B Capture to force a play inside?
$$ --------------
$$ | . . . O . . .
$$ | . X X O . . .
$$ | O O O X O O O
$$ | O c O X b . .
$$ | X X O X O . .
$$ | . a X O O O O
$$ | . . X X X X X
$$ | . . . . . . .[/go]

If white wants to force black to connect at a (filling in a point of territory), she needs to capture at b before filling the dame point c. Likewise, black could atari, to force a capture at b, but would then need to connect at a afterwards.

Or, both players could be apathetic and just let the situation be at the end of the game. I suppose it's moot for scoring purposes, so it's a net zero points, and therefore not worth playing by either player, but are a and b territory then? Again, it's moot because it's net zero points, but are they technically required to play? (e.g. during the dame-filling stage in Japanese rules)

Author:  RobertJasiek [ Wed Mar 09, 2011 3:10 am ]
Post subject:  Re: Weirdish position

Area scoring: A player wishing to get C needs to play before scoring.

Territory scoring: It depends on the ruleset. In particular J1989 / J2003: C is a dame so that either adjacent "group" is in-seki and there is no territory on the board yet. Verbal Japanese Rules are more liberal.

Author:  freegame [ Wed Mar 09, 2011 5:47 am ]
Post subject:  Re: Weirdish position

It's Teire Dame I think.

Author:  fwiffo [ Wed Mar 09, 2011 11:38 am ]
Post subject:  Re: Weirdish position

Thanks, that makes sense.

Author:  willemien [ Sat Mar 12, 2011 4:04 am ]
Post subject:  Re: Weirdish position

Click Here To Show Diagram Code
[go]$$B Startposition
$$ --------------
$$ | . . . O . . .
$$ | . X X O . . .
$$ | O O O X O O O
$$ | O c O X b . .
$$ | X X O X O . .
$$ | . a X O O O O
$$ | . . X X X X X
$$ | . . . . . . .[/go]


I like the Ikeda area III rules http://senseis.xmp.net/?IkedasRule
and here is my analyse of the position using these rules.

All have the startingpoint that there have been no passes before. (under these rules white get a point more if he passes first, but in a rather complex way, i keep here to the original description)
I don't claim to be an expert here so please comment than we can all learn together :study:

I think the main playouts to concider are:

1a) - Black to move Bpass - Wb- Bpass-Wc- Ba

result (after removing dead stones)
Click Here To Show Diagram Code
[go]$$B Endposition 1a
$$ --------------
$$ | w w w O w w w
$$ | w w w O w w w
$$ | O O O w O O O
$$ | O 4 O w 2 w w
$$ | X X O w O w w
$$ | b 5 X O O O O
$$ | b b X X X X X
$$ | b b b b b b b[/go]

so white 37 area
black 19 area
Difference 18 to white

1b) - Black to move -Ba - Wb- Bpass-Wc

result (after removing dead stones)
Click Here To Show Diagram Code
[go]$$B Endposition 1b
$$ --------------
$$ | w w w O w w w
$$ | w w w O w w w
$$ | O O O w O O O
$$ | O 4 O w 2 w w
$$ | X X O w O w w
$$ | b 1 X O O O O
$$ | b b X X X X X
$$ | b b b b b b b[/go]

white 37 area
black 19 area
difference 18 to white

1c) - Black to move Ba - Wb- Bc-Wpass

result (after removing dead stones)
Click Here To Show Diagram Code
[go]$$B Endposition 1c
$$ --------------
$$ | w w w O w w w
$$ | w w w O w w w
$$ | O O O w O O O
$$ | O 3 O w 2 w w
$$ | X X O w O w w
$$ | b 1 X O O O O
$$ | b b X X X X X
$$ | b b b b b b b[/go]

white 36 area + 1/2 point for white passing first
black 20 area - 1/2 point for white passing first

so white 36 1/2 point
black 19 1/2 point
difference 17 to white

2a) - White to move Wb- Bpass-Wc- Ba

result (after removing dead stones)
Click Here To Show Diagram Code
[go]$$W Endposition 2a
$$ --------------
$$ | w w w O w w w
$$ | w w w O w w w
$$ | O O O w O O O
$$ | O 3 O w 1 w w
$$ | X X O w O w w
$$ | b 4 X O O O O
$$ | b b X X X X X
$$ | b b b b b b b[/go]

white 36 area + 1/2 point for white passing first
black 20 area - 1/2 point for white passing first

so white 36 1/2 point
black 19 1/2 point
difference 17 to white

2b) - White to move Wpass- Ba-Wb- Bc

result (after removing dead stones)
Click Here To Show Diagram Code
[go]$$W Endposition 2b
$$ --------------
$$ | w w w O w w w
$$ | w w w O w w w
$$ | O O O w O O O
$$ | O 4 O w 3 w w
$$ | X X O w O w w
$$ | b 2 X O O O O
$$ | b b X X X X X
$$ | b b b b b b b[/go]

white 36 area + 1/2 point for white passing first
black 20 area - 1/2 point for white passing first

so white 36 1/2 point
black 19 1/2 point
difference 17 to white


So taking these all for black best is to play Ba followed by Bc
And for white passing or capturing makes no difference.
but do :study: maybe i made a mistake

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