Question regarding AGA vs Territory/Area scoring

[Bill Spight]

Similar position in chilled go ( http://senseis.xmp.net/?ChilledGo ).

Chilled go has a similar relation to territory go as territory go has to area go. In area go every stone of yours on the board counts for you; in chilled go every stone of yours on the board counts against you.

$$Bc Chilled go jigo
$$--------------
$$ | . X X . O |
$$ | X X O X O |
$$ | . X O O O |
$$ | X X O . O |
$$ | . X . O . |
$$--------------

Click Here To Show Diagram Code

[go]$$Bc Chilled go jigo
$$--------------
$$ | . X X . O |
$$ | X X O X O |
$$ | . X O O O |
$$ | X X O . O |
$$ | . X . O . |
$$--------------[/go]

The Japanese dame on the bottom side is no-man's-land. Neither player will play there, because to do so would lose a point. The position in the top right is the chilled go equivalent of a dame, called a star.

$$Bc Black plays
$$--------------
$$ | . X X 1 O |
$$ | X X O B O |
$$ | . X O O O |
$$ | X X O . O |
$$ | . X . O . |
$$--------------

Click Here To Show Diagram Code

[go]$$Bc Black plays
$$--------------
$$ | . X X 1 O |
$$ | X X O B O |
$$ | . X O O O |
$$ | X X O . O |
$$ | . X . O . |
$$--------------[/go]

If saves the stone, Black will have one more pt. of territory than White, but will have one more stone on the board, for jigo.

$$Wc White plays
$$--------------
$$ | . X X 1 O |
$$ | X X O B O |
$$ | . X O O O |
$$ | X X O . O |
$$ | . X . O . |
$$--------------

Click Here To Show Diagram Code

[go]$$Wc White plays
$$--------------
$$ | . X X 1 O |
$$ | X X O B O |
$$ | . X O O O |
$$ | X X O . O |
$$ | . X . O . |
$$--------------[/go]

If captures the stone, play will end and the stone will be used to fill in the Black territory.

$$Bc Jigo
$$--------------
$$ | B X X O O |
$$ | X X O . O |
$$ | . X O O O |
$$ | X X O . O |
$$ | . X . O . |
$$--------------

Click Here To Show Diagram Code

[go]$$Bc Jigo
$$--------------
$$ | B X X O O |
$$ | X X O . O |
$$ | . X O O O |
$$ | X X O . O |
$$ | . X . O . |
$$--------------[/go]

White has one more pt. of territory than Black, but has one more stone on the board than Black, for jigo.

The player who on the last play of the game takes a star in chilled go for jigo wins by territory scoring, and the player who on the last play of the game fills a dame in territory go wins by area scoring.

[EdLee]

We don't do komi = 0.5, which would change the winner.

snorri, this is exactly my confusion. When komi = 0.0, and when komi = 0.5, Chinese scoring and Japanese scoring give different winners (for the above final board position).

[DrStraw]

I seems to me the height of arrogance for an upstart neophyte go playing country like the USA to try to tell the rest of the world that they have it wrong. Japanese rules have worked since before the USA was even populated by westerners, let alone be a go asssociation.

Actually I think the best reason to use AGA rules (or Area scoring) is because we are a neophyte go playing country. Japanese rules requires judges or arbiters for decisions. Many tournaments in this country occur, and we do not have many strong players around in all parts of the country to make these decisions. AGA rules let people play and score the game as they learned with the benefit that any tournament director can just tell players to play out any situations and not change the score.

I played my first tournament in 1974. I have yet to play a single game where there has been an issue by playing Japanese rules.

[oren]

I played my first tournament in 1974. I have yet to play a single game where there has been an issue by playing Japanese rules.

None of my games have had issues, but I've played since 2002 and seen a couple. I've also seen lots of beginners confused by whether or not they have to play inside their own territory and what it meant for the score.

[ez4u]

Similar position in chilled go ( http://senseis.xmp.net/?ChilledGo ).

Chilled go has a similar relation to territory go as territory go has to area go. In area go every stone of yours on the board counts for you; in chilled go every stone of yours on the board counts against you.

$$Bc Chilled go jigo
$$--------------
$$ | . X X . O |
$$ | X X O X O |
$$ | . X O O O |
$$ | X X O . O |
$$ | . X . O . |
$$--------------

Click Here To Show Diagram Code

[go]$$Bc Chilled go jigo
$$--------------
$$ | . X X . O |
$$ | X X O X O |
$$ | . X O O O |
$$ | X X O . O |
$$ | . X . O . |
$$--------------[/go]

The Japanese dame on the bottom side is no-man's-land. Neither player will play there, because to do so would lose a point. The position in the top right is the chilled go equivalent of a dame, called a star.

$$Bc Black plays
$$--------------
$$ | . X X 1 O |
$$ | X X O B O |
$$ | . X O O O |
$$ | X X O . O |
$$ | . X . O . |
$$--------------

Click Here To Show Diagram Code

[go]$$Bc Black plays
$$--------------
$$ | . X X 1 O |
$$ | X X O B O |
$$ | . X O O O |
$$ | X X O . O |
$$ | . X . O . |
$$--------------[/go]

If saves the stone, Black will have one more pt. of territory than White, but will have one more stone on the board, for jigo.

$$Wc White plays
$$--------------
$$ | . X X 1 O |
$$ | X X O B O |
$$ | . X O O O |
$$ | X X O . O |
$$ | . X . O . |
$$--------------

Click Here To Show Diagram Code

[go]$$Wc White plays
$$--------------
$$ | . X X 1 O |
$$ | X X O B O |
$$ | . X O O O |
$$ | X X O . O |
$$ | . X . O . |
$$--------------[/go]

If captures the stone, play will end and the stone will be used to fill in the Black territory.

$$Bc Jigo
$$--------------
$$ | B X X O O |
$$ | X X O . O |
$$ | . X O O O |
$$ | X X O . O |
$$ | . X . O . |
$$--------------

Click Here To Show Diagram Code

[go]$$Bc Jigo
$$--------------
$$ | B X X O O |
$$ | X X O . O |
$$ | . X O O O |
$$ | X X O . O |
$$ | . X . O . |
$$--------------[/go]

White has one more pt. of territory than Black, but has one more stone on the board than Black, for jigo.

The player who on the last play of the game takes a star in chilled go for jigo wins by territory scoring, and the player who on the last play of the game fills a dame in territory go wins by area scoring.

Isn't the ability to refuse to fill in the last dame on C1 what produces the the difference in this case? If the players had to fill in the dame at the end of the game, would this revert to territory (or AGA or something)?

[jts]

We don't do komi = 0.5, which would change the winner.

snorri, this is exactly my confusion. When komi = 0.0, and when komi = 0.5, Chinese scoring and Japanese scoring give different winners (for the above final board position).

Yes, this is a general issue. With no komi, black has one more point than white in 1/2 of games (dame polarity). And whenever white has a fixed komi, black will still have one more point under area scoring than under territory scoring in 1/2 of games. But in fact, China has historically tended to offer one more point of komi (well, an extra 0.5 zi) in komi than the Japanese and Koreans do, so in practice it is white who has an extra point in 1/2 of games when people use area rules.

In effect, white's extra pass under AGA rules is a way to give back one point of the Chinese-style 7.5 komi (if I understand correctly). I'm sure I will swiftly corrected by someone who is better at arithmetic...

[Bill Spight]

Similar position in chilled go ( http://senseis.xmp.net/?ChilledGo ).

Chilled go has a similar relation to territory go as territory go has to area go. In area go every stone of yours on the board counts for you; in chilled go every stone of yours on the board counts against you.

$$Bc Chilled go jigo
$$--------------
$$ | . X X . O |
$$ | X X O X O |
$$ | . X O O O |
$$ | X X O . O |
$$ | . X . O . |
$$--------------

Click Here To Show Diagram Code

[go]$$Bc Chilled go jigo
$$--------------
$$ | . X X . O |
$$ | X X O X O |
$$ | . X O O O |
$$ | X X O . O |
$$ | . X . O . |
$$--------------[/go]

The Japanese dame on the bottom side is no-man's-land. Neither player will play there, because to do so would lose a point. The position in the top right is the chilled go equivalent of a dame, called a star.

$$Bc Black plays
$$--------------
$$ | . X X 1 O |
$$ | X X O B O |
$$ | . X O O O |
$$ | X X O . O |
$$ | . X . O . |
$$--------------

Click Here To Show Diagram Code

[go]$$Bc Black plays
$$--------------
$$ | . X X 1 O |
$$ | X X O B O |
$$ | . X O O O |
$$ | X X O . O |
$$ | . X . O . |
$$--------------[/go]

If saves the stone, Black will have one more pt. of territory than White, but will have one more stone on the board, for jigo.

$$Wc White plays
$$--------------
$$ | . X X 1 O |
$$ | X X O B O |
$$ | . X O O O |
$$ | X X O . O |
$$ | . X . O . |
$$--------------

Click Here To Show Diagram Code

[go]$$Wc White plays
$$--------------
$$ | . X X 1 O |
$$ | X X O B O |
$$ | . X O O O |
$$ | X X O . O |
$$ | . X . O . |
$$--------------[/go]

If captures the stone, play will end and the stone will be used to fill in the Black territory.

$$Bc Jigo
$$--------------
$$ | B X X O O |
$$ | X X O . O |
$$ | . X O O O |
$$ | X X O . O |
$$ | . X . O . |
$$--------------

Click Here To Show Diagram Code

[go]$$Bc Jigo
$$--------------
$$ | B X X O O |
$$ | X X O . O |
$$ | . X O O O |
$$ | X X O . O |
$$ | . X . O . |
$$--------------[/go]

White has one more pt. of territory than Black, but has one more stone on the board than Black, for jigo.

The player who on the last play of the game takes a star in chilled go for jigo wins by territory scoring, and the player who on the last play of the game fills a dame in territory go wins by area scoring.

Isn't the ability to refuse to fill in the last dame on C1 what produces the the difference in this case?

The Japanese dame makes jigo possible for this kind of position.

If the players had to fill in the dame at the end of the game, would this revert to territory (or AGA or something)?

If there were no kos or super kos, then you could view territory go as a form of area go, and chilled go as a form of territory go. Then if you won chilled go you would win territory go, and you would also win jigo if you got the last move. And if you won territory go you would win area go, and if you got the last move in jigo in territory go you would also win area go.

If you make them a form of no pass go (so that somebody would have to fill the Japanese dame), then they become different phases of the same game, and you could stop play at the stage of chilled go and score the game. The trouble is, the score at that stage may have fractions. To get integers you have to continue to territory go.

And, as we know, beginner problems aside, kos that are not resolved at the level of territory go can cause rules headaches.

[skydyr]

My understanding of scoring differences between area and territory scoring are that originally, group tax aside, go was scored using territory scoring, with the caveat that both sides had to play an equal number of plays. Passing was not a move, but games ended when players agreed they were done.

In China, it was decided that counting by area was easier to do and was equivalent to the old scoring, so this change didn't affect the scores.

In Japan, territory scoring was brought over with go originally, but the rule requiring that both players play equal numbers of stones was at some point lost (similar to the change to an empty board at the beginning from cross-hoshi). You will notice than in the example given, if both players are required to play an equal number of moves, white's last move fills in a point of white's territory, returning to the same result as with area scoring.

AGA-style territory scoring restores the requirement for both players to play an equal number of stones. Incidentally, it also counts eyes in seki, like chinese rules, but that's a different topic.

[Magicwand]

ppl think that the result will differ by only one point but!
i can give you examples of same game that the result differ by more than 10 points.

correct me if i am wrong... in chinese rule territories in seki can be converted into points.
in japanese rule it is all dame.
as a result it is possible to have different result differ by multiple points.

[skydyr]

ppl think that the result will differ by only one point but!
i can give you examples of same game that the result differ by more than 10 points.

correct me if i am wrong... in chinese rule territories in seki can be converted into points.
in japanese rule it is all dame.
as a result it is possible to have different result differ by multiple points.

This is true, but situations where there are sekis and one side has more points in eyes in seki than the other seem like they would be pretty rare.

[xed_over]

ppl think that the result will differ by only one point but!
i can give you examples of same game that the result differ by more than 10 points.

so you'd better be sure which rule set you're using before you start playing.

[RobertJasiek]

Japanese rules have worked since before the USA was even populated by westerners

In this case, "Japanese rules" refers to rules with the concept of perfect hypothetical play. Since this concept relies on arbitrarily great finite or infinite numbers of hypothetical sequences and decisions, not the Japanese rules themselves have worked, but the illusion of approximating them by verbal means.

I played my first tournament in 1974. I have yet to play a single game where there has been an issue by playing Japanese rules.

In this case, probably "Japanese rules" refers to a Western verbal approximisation ("verbal Japanese rules"), which does not or not as seriously care about the concept of perfect hypothetical play. So if you did not meet beginners with difficulties to understand such rules or tournament players insisting on (too) strict rules application, your experience has been possible for you.

In the end, all of the debate is about stuff that rarely happens anyway.

Citing Thatcher: "No, no, no, no!" The core of the debate is the insistance of professional style Japanese rules with their concept of perfect hypothetical play and its arbitrarily great finite or infinite numbers of hypothetical sequences and decisions. They happen for EACH game end position (regardless of whether the players mention or forgo them in practice).

[DrStraw]

Robert, go is an oriental game. You really need to stop thinking of it with an occidental mentality. You lose most of the fascination with it when you do that. It is like trying to understand Buddhism or Hinduism from a monotheistic point of view.

Slow down and look at the trees instead of spending all your time trying to count the leaves.

[dumbrope]

Robert, go is an oriental game.

It is interesting that you didn't say a Japanese game. For the AGA to have its own ruleset is in some sense less political than taking sides. We have Japanese, Koreans, Chinese, and others in our tournaments. At least they are all equally confused.

[DrStraw]

Correct, I did not same Japanese. Oriental culture in general tends to be a little more vague (sometimes much more) than occidental, and that is part of its attraction.