Re: my problems with aga rules (from godiscussions)

[xed_over]

http://www.godiscussions.com/forum/show ... hp?t=11587

so, this is a very nit picky point but one worth stating imho.

AGA is my personal favorite ruleset. it uses japanese scoring (a big plus for me.) makes points in seki count (another huge one.) while balancing the komi with the pass stone rule. (since game can't end on white turn, this makes the komi of 7.5 somewhat more managable for black.) so what's my nit pick? i'll demonstrate.

imagine you come to the end on the game and then white plays an ignorable move.

$$W
$$ |-------------------|
$$ | 1 . . . . . . . . |
$$ | . . . . . . . . . |
$$ | . . X . X . X X X |
$$ | X X . . . X O O O |
$$ | O O X X X O . . . |
$$ | . O O O O . O . . |
$$ | . . . . . . . . . |
$$ | . . . . . . . . . |
$$ | . . . . . . . . . |
$$ |-------------------|

Click Here To Show Diagram Code

[go]$$W
$$ |-------------------|
$$ | 1 . . . . . . . . |
$$ | . . . . . . . . . |
$$ | . . X . X . X X X |
$$ | X X . . . X O O O |
$$ | O O X X X O . . . |
$$ | . O O O O . O . . |
$$ | . . . . . . . . . |
$$ | . . . . . . . . . |
$$ | . . . . . . . . . |
$$ |-------------------|[/go]

black sees that this move can be ignores and so passes.
then white passes.
then that would be the game, and white would lose a point.
but now lets take the same senario and see what happens when black does the same.

$$
$$ |-------------------|
$$ | . . . . . . . . . |
$$ | . . . . . . . . . |
$$ | . . X . X . X X X |
$$ | X X . . . X O O O |
$$ | O O X X X O . . . |
$$ | . O O O O . O . . |
$$ | . . . . . . . . . |
$$ | . . . . . . . . . |
$$ | . . . . . . . . 1 |
$$ |-------------------|

Click Here To Show Diagram Code

[go]$$
$$ |-------------------|
$$ | . . . . . . . . . |
$$ | . . . . . . . . . |
$$ | . . X . X . X X X |
$$ | X X . . . X O O O |
$$ | O O X X X O . . . |
$$ | . O O O O . O . . |
$$ | . . . . . . . . . |
$$ | . . . . . . . . . |
$$ | . . . . . . . . 1 |
$$ |-------------------|[/go]

now white passes, black passes, and because of the move rule, white must pass again to end the game. thus black doesn't really lose a point.

this seems slightly unfair to me. black can invade with impunity but white cannot?

The problem, Phillip, is with your first diagram. Its not White's turn. Each player has played 11 moves (and assuming no captures), its now black's turn. So if black passes first (handing over a stone), then white plays , white gains the point otherwise "lost" from black's pass stone.

[Li Kao]

it uses japanese scoring (a big plus for me.) makes points in seki count (another huge one.) while balancing the komi with the pass stone rule.

In what way are these rules Japanese? They use area-scoring, super-ko, points in seki and their dame are worth a point. Sounds like the exact opposite of Japanese rules to me.

[dfan]

AGA rules give the option of using either area or territory scoring. Only in the former case are dame worth a point. The use of pass stones makes the two scores equivalent.

[Bill Spight]

xed_over is right, Phillip.

The reason that White passes last with pass stones is to make the number of Black stones and the number of White stones equal during counting. That way you can ignore the stones and simply count territory. (And I should know, I came up with the idea when writing an article for the AGA Journal years ago. Others also discovered it independently. )

So it cannot be White's move in your first diagram unless Black has passed, and White has an extra Black stone. Then everything works out.

[daniel_the_smith]

AGA rules give the option of using either area or territory scoring. Only in the former case are dame worth a point. The use of pass stones makes the two scores equivalent.

Dame are worth points under AGA rules, no matter how you score the board at the end. (Consider the implications of your last sentence )

In what way are these rules Japanese? They use area-scoring, super-ko, points in seki and their dame are worth a point. Sounds like the exact opposite of Japanese rules to me.

Only in the sense that you may count the board in the Japanese way at the end of the game.

[dfan]

AGA rules give the option of using either area or territory scoring. Only in the former case are dame worth a point. The use of pass stones makes the two scores equivalent.

Dame are worth points under AGA rules, no matter how you score the board at the end. (Consider the implications of your last sentence )

Right, OK, I was thinking of the case in which both players are pretending to play by Japanese rules, but you're right, even in that case you're passing up points by not playing dame.

[daniel_the_smith]

Life became simpler when I realized that AGA rules are really area rules that you can count however you want.

[Harleqin]

It uses japanese scoring (a big plus for me), makes point in seki count (another huge one), while balancing the komi with the pass stone rule.

In what way are these rules Japanese? They use area-scoring, super-ko, points in seki and their dame are worth a point. Sounds like the exact opposite of Japanese rules to me.

I think he means territory counting (not scoring).

On a side note, I think that it would be good for the notion of "japanese rules" if they were just associated with territory scoring, instead of getting the additional burden of a dozen ostensible corner cases arbitrarily decided based on ad hoc ideas.

The difference between area and territory scoring is just the button, by the way.