AGA Rules / Discussion

Sub-page of AGARules

RobertJasiek: jettero, NNGS uses NNGS-Japanese rules, not Japanese rules. KGS uses KGS-Japanese rules, not Japanese rules. IGS uses IGS rules, not Japanese rules. I do not know about DGS, but I would be surprised if it were Japanese rules; more likely it is DGS-Korean rules...

jettero: I have a question about rule number 7 in the AGA.

On NNGS, DGS, KGS, and IGS; when the japanese rules are in effect: If your opponent makes a stupid throw-in you don't have to respond to, you can pass and get a free point. I like that.

In the AGA rules -- I was shocked to find out at a tournament in Chicago -- they're fully encouraged to try their stupid moves because it doesn't cost them anything. Because of rule number 7, you have to give them a stone every time you pass. Am I misunderstanding the rule?

Also, there was a general perception that white must pass (a stone) last. Is that also true?

Bill: No, you are not misunderstanding the rules. The AGA rules use, in effect, area scoring, which counts open points surrounded by live stones of one color plus those live stones, but not captured stones or dead stones. There is a style of territory counting that gives the same results by not counting live stones, but by counting pass stones in addition to captured stones and dead stones.

By using pass stones, with White passing last, when the score is tallied, each player has the same number of stones on the board. So you can ignore the stones and just count the territory.

These rules do have the effect you mention. However, they appear to alleviate some problems beginners have with deciding life and death and ending the game. When players get better, they have fewer problems with those decisions and are much less likely to make the kind of needless play you are talking about.

jettero: This is interesting. In every single game I played on Saturday (6 games actually), people were passing stones and filling territory with captures. It would seem we were all mixing japanese and chinese scoring.

StormCrow: If you aren't using area (chinese) counting, that is the proper way to score AGA style (filling the prisoners back in, including pass stones, and then counting the spaces). With area scoring, it doesn't matter if you keep prisoners or not, the count comes out the same either way.

Bill: Jettero, with pass stones you do fill territory with captures, dead stones, and pass stones before counting the territory. That's really Chinese-style scoring, but with a Japanese-style counting method. ;-)

jettero: OK, now I really really don't understand the pass stones... Is there some way to clarify for me? Presently I'm planning on counting some things on my 9x9 board at home... Wait, I think I get it... But we were not counting the stones, just the open moku. The only way I can figure that it doesn't matter if you count caps or not is if you count the stones too. I think you said above that you are supposed to count the stones, but we did not.

rubilia: AGA rules ensure that the total amount of played stones of each colour in a game is equal. The surrounded territory counts both ways, and about the stones, you arbitrarily can count either living stones or prisoners, because the difference will be the same. Actually, you can find lots of counting techniques, but scoring there are only two main rule ideas of: chinese "area scoring" and japanese "territory scoring". AGA rules use the chinese one.

Bill: Here is an example on a 5x5 board.

[Diagram]

Pass stones

W5, B6, W7 = pass

Black's pass, B6, ends the contest, but White must make a final pass.

[Diagram]

Counting

To count, White's two pass stones, WC, are placed in White's territory, and Black's pass stone, BC, is, too. Also, to make it easier to count, one of Black's stones, BS, is moved slightly.

Black has 5 points of territory to 4 points for White. Black wins by 1 point.

If we counted area directly, the score would be 13 to 12, also a 1 point win for Black. White's final pass made the number of stones for each side the same (8), so the stones could be ignored in counting.

Es claro?

Mef: Just for clarification, under Japanese rules, would white get a jigo?

Bill: Yes, it's a jigo under Japanese rules.

Mef: Thanks, that's what I thought, just making sure.

jettero: OK, I see how the Japanese and Chinese counting rules look similar. The part that frustrated me, and the whole reason I brought it up, was my free points. What if the board is all set, and black makes a pointless throwin. [1]

[Diagram]

My First Question

W2, W4, W6, B7, W8 = pass

On KGS I get a free point for each move I can ignore. In the AGA rules I don't. That's what really upset me. I want black to lose something for playing the strange pointless moves... If he get's one of my white stones every time, I don't get my free points.

Apparently I am understanding the rule correctly, I just don't like it.


RobertJasiek: Under AGA Rules, your example should go as follows:

[Diagram]

Answer dia 1

pass = B5, B7, B9

[Diagram]

Answer dia 2

RobertJasiek: Since Sensei does not allow move numbers greater than 10, I have to start with 1 for move 11, sigh.

yoyoma: You can use a zero (0) for move 10 on Sensei diagrams. I updated these diagrams using that. At least even/odd still matches white/black.

pass = B1, B3, W4.

[Diagram]

Answer dia 3


Territory Counting for AGA Rules:

White prisoner stones made before your diagram and scoring for Black = 0
Black prisoner stones made before your diagram and scoring for White = 0
White pass stones played before your diagram and scoring for Black = 0
Black pass stones played before your diagram and scoring for White = 1
Black points on board = 16
White points on board = 10
White prisoner stones made after your diagram and scoring for Black = 0
Black prisoner stones made after your diagram and scoring for White = 2
White pass stones played after your diagram and scoring for Black = 1
Black pass stones played after your diagram and scoring for White = 5

Sum of Territory Count = 0 - 0 + 0 - 1 + 16 - 10 + 0 - 2 + 1 - 5 = -1

This agrees to the Area Count = 24 - 25 = -1.

Note: You have offered a doubtful diagram that requires a careful analysis of prisoners and passes before it could have been reached. Only therefore I have to include four more numbers in the Territory Counting calculation than normally necessary.


[1]: yoyoma: I understand that you have a problem with the rules not penalizing pointless moves in the endgame. But you should also realize that there is an advantage gained: If you and your opponent do not agree about the life/death status of stones at the end of the game, you can play the game out and any dead groups can be actually captured without losing points (see rule #10 - Disputes). Also as a practical matter, many times these pointless invasions are launched while there are still dame left on the board. In this case, you can still gain points by playing the dame.


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