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AGA rules and passing stones
http://www.lifein19x19.com/viewtopic.php?f=45&t=17560
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Author:  phillip1882 [ Tue Aug 11, 2020 11:17 am ]
Post subject:  Re: AGA rules and passing stones

what i dont get about aga rules is the following
take this following position
Click Here To Show Diagram Code
[go]$$c dame problem
$$ ------------
$$ | . X X O . |
$$ | . X . O . |
$$ | . X . O . |
$$ | . X O O . |
$$ ------------[/go]


if its black to play first, c3, with white c2, and then both pass.
but if white plays first, c2, then black c3. after they both pass, white has to pas yet again giving up a stone.
under chinese rules this extra stone doesn't count.
but under japanese rules it does.
which rule set should we use?

Author:  Bill Spight [ Tue Aug 11, 2020 11:36 am ]
Post subject:  Re: AGA rules and passing stones

phillip1882 wrote:
what i dont get about aga rules is the following
take this following position
Click Here To Show Diagram Code
[go]$$c dame problem
$$ ------------
$$ | . X X O . |
$$ | . X . O . |
$$ | . X . O . |
$$ | . X O O . |
$$ ------------[/go]


if its black to play first, c3, with white c2, and then both pass.
but if white plays first, c2, then black c3. after they both pass, white has to pas yet again giving up a stone.


How is it White's turn?

The purpose of the pass stones in AGA rules, in an even game, is to make the number of stones the same for each side when the score is counted, so that the difference between the territory scores is the same as the difference between the area scores. (I know, because I proposed pass stones in the AGA Journal in the 1970s. :)) If White plays first in this position that does not happen, unless somehow White has captured one more stone than Black to reach this position. How did that happen?

Edit: Oh, of course. ;) Black has passed, giving White a pass stone. That's why it is White's play. :)

Author:  gennan [ Tue Aug 11, 2020 11:37 am ]
Post subject:  Re: AGA rules and passing stones

phillip1882 wrote:
...
which rule set should we use?

Use whatever rule set you agreed on before starting the game.

Author:  RobertJasiek [ Tue Aug 11, 2020 10:46 pm ]
Post subject:  Re: AGA rules and passing stones

phillip1882 wrote:
what i dont get about aga rules is the following
take this following position
Click Here To Show Diagram Code
[go]$$c dame problem
$$ ------------
$$ | . X X O . |
$$ | . X . O . |
$$ | . X . O . |
$$ | . X O O . |
$$ ------------[/go]


if its black to play first, c3, with white c2, and then both pass.
but if white plays first, c2, then black c3. after they both pass, white has to pas yet again giving up a stone.
under chinese rules this extra stone doesn't count.
but under japanese rules it does.
which rule set should we use?


You are asking about AGA Rules so I think that you mean "area counting for area scoring" when mistakenly you write "Chinese Rules" and mean "territory counting for area scoring" when mistakenly you write "Japanese Rules". (Chinese Rules and Japanese Rules do not use pass stones. AGA Rules use pass stones so that both area counting and territory counting determine the area score.)

There are equal numbers of black and white stones on the board.

If it is Black's turn, previously the players have made equal numbers of moves. (If they have made earlier passes, they have made equal numbers of earlier passes and have paid equal numbers of pass stones. If they have made earlier removals, they have removed equal numbers of black and white stones.)

If it is White's turns, previously Black has made one excess move and paid one excess pass stone. (If the players have made earlier passes or removals, the combined net effect would equal that of just observing that Black has made one excess move and paid one excess pass stone.)

If the position is the artificial starting position with Black's turn, this is like having started from the empty board with Black's turn.

If the position is the artificial starting position with White's turn, this does not behave like having started from the empty board with Black's turn. Instead, you confuse yourself when nevertheless assuming to be studying AGA Rules. AGA Rules work, in particular, because Black starts the game and White ends the game so that the players make an equal number of moves throughout the game. Your artificial starting position with White's turn does not work (does not equal area counting for area scoring and territory counting for area scoring) because White starts and ends your artificial game.

Your question what ruleset to use is misleading because you confuse rulesets with counting methods. For AGA Rules, use either area counting or territory counting (you can use either because they equally determine the area score). If, however, your broader question is whether to AGA Rules, Chinese Rules or Japanese Rules, you first need to clarify which Chinese Rules and which Japanese Rules. Next, you should educate yourself about the various rulesets: http://home.snafu.de/jasiek/rules.html

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