AGA Rules vs. Japanese

[hailthorn011]

Hello, I'm an 11k player on KGS, and I've always played using Japanese scoring. However, today I'm going to be participating in a tournament that uses AGA rules. Is it possible to play the same way with both sets of rules?

I've looked over the rulesets and I can't really see anything drastically different, but I just thought I'd ask so I know ahead of time what I'm getting myself into.

[robinz]

I'm no expert, but the main difference is going to be due to the fact that AGA rules essentially use area scoring. This means that you need to actually fill in all the dame at the end of the game, or you will lose a point every time you pass and your opponent gets one. (Perhaps you always fill them in anyway, but I've noticed most players on KGS don't, and even I've started to be lazy and not do so.)

Eyes in seki are also counted as points under AGA rules, but not under Japanese ones, but it's rare for this to make any difference (I've certainly never noticed a situation in any of my own games where there would be on).

That's about it as far as I know, but I'm sure the rules experts can point out more

[jts]

Under AGA rules, if you have the opportunity to start a ko in the endgame, you should do so when you're behind on points; under Japanese rules, you should never do so.

So if W needs an extra point to win, he can play at b and try to win the ko to get two points (one for a, one for b), while if he doesn't, he can just play at a for one point. But if you're playing Japanese rules, W loses a point for playing at b as soon as B captures, and then W has to win the ko just to break even.

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$$ | . . . O X .
$$ | . . O O X X
$$ | . . O a b X
$$ | - - - - - -

Click Here To Show Diagram Code

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$$ | . . . O X .
$$ | . . . O X .
$$ | . . O O X X
$$ | . . O a b X
$$ | - - - - - -[/go]

(Did I get that right?)

[hailthorn011]

First off, thank you two for trying to explain it to me.

But now I know why I prefer Japanese scoring. It's so much simpler. Or perhaps I feel that way because it's the only rule set I've over used.

Oh well, I guess this is what I get for never trying out other rule sets.

But I'm curious, could a win in Japanese scoring be a loss in AGA scoring? That's my big concern. I'm not familiar with area scoring at all. I kind of get the gist from what you two have said, but it's not really something I've used before.

[Laman]

But I'm curious, could a win in Japanese scoring be a loss in AGA scoring? That's my big concern. I'm not familiar with area scoring at all. I kind of get the gist from what you two have said, but it's not really something I've used before.

EDIT: if i recall correctly, AGA rules are designed to give equal results for both territory and area scoring

[my original message]
yes, the score difference may not be the same and so for close scores the results given by different rulesets may be different

but it generally applies to half point games which are quite rare. and even if you were to end so close, i guess you wouldn't know the exact difference before the end and counting the score so you can happily play as always. there is only distinct possibility that the ruleset would change the outcome of your game

more serious is for example when chinese pro used to area scoring play an international tournament with territory scoring and forget to keep track of prisoners (which are not important for area scoring). in such case he may get into trouble (losing points) but you can stay calm
[/my original message]

[Harleqin]

The view from the other side:

When you are used to AGA rules, japanese rules differ in some strange ways. The most glaring difference is that you do not play until all points have been taken, but just until only one-point moves are left. This can, of course, make a difference when an odd number of such moves is available. Such moves are also made to be worth 0 points. That would break the fundamental rule that a pass is always worth one point less than playing a one-point move, but it works out in almost any case, as long as the players agree. In the case of disagreement, the game cannot simply go on, because of that quirk. There are special encore rules for making the result similar to AGA rules, but that is also not guaranteed.

There are other differences, but this is the most difficult one.

[RobertJasiek]

Differences of scorings:

http://home.snafu.de/jasiek/asintro.pdf
http://home.snafu.de/jasiek/diffasts.html
http://home.snafu.de/jasiek/kodame.pdf

AGA scoring:

It is area scoring. It is not territory scoring. It lets counting methods for area scoring determine the same result as counting methods for territory scoring.

Japanese scoring. It's so much simpler.

Let me correct your false belief:

http://www.cs.cmu.edu/%7Ewjh/go/rules/Japanese.html
http://home.snafu.de/jasiek/j1989c.html
http://home.snafu.de/jasiek/j2003.html
http://home.snafu.de/jasiek/j2003inf.html
http://home.snafu.de/jasiek/j2003com.html
http://home.snafu.de/jasiek/wagc.html
http://home.snafu.de/jasiek/wagcflaw.html
http://home.snafu.de/jasiek/wagcmod.html
http://home.snafu.de/jasiek/simple.html
http://home.snafu.de/jasiek/simpcom.html

Conclusion: Japanese scoring is extremely many times as difficult as area scoring. My time needed to understand Japanese scoring was ca. 24 years - the time for area scoring 5 minutes. The factor is 2,524,554. That much more difficult is Japanese scoring. (Nowadays my explanations are available and a few weeks to read and understand them might suffice. Still that is much more than 5 minutes.)

[John Fairbairn]

Conclusion: Japanese scoring is extremely many times as difficult as area scoring. My time needed to understand Japanese scoring was ca. 24 years - the time for area scoring 5 minutes. The factor is 2,524,554.

We've told you a million times never to exaggerate. An 11-year-old youngster can even start earning a living in go under Japanese rules without ever having studied them.

If you want to understand or deal with every possible anomaly that can occur in a game of go, it is true that Japanese rules can be vexing. But the anomalies either occur very, very, very rarely (never in a lifetime in some cases) or can be dealt with by ultra-simple fiats (e.g. triple ko is a draw), and so don't matter much in practice.

There is a reasonable case to be made for AGA rules for beginners, but beyond a certain, rather early stage in one's playing career, that loses force. In practice all pros seem to prefer territory counting in that, during a game, even Chinese pros count that way in their heads. They also routinely ignore arcana such as the superko rules. There is even a suspicion that Chinese pros resign more than Japanese and Korean pros, to avoid what they regard as counting hassle.

This is not so much an argument for Japanese rules as a plea for less overblown diatribes against them.

For the OP, I have been told several times that even in US events with AGA rules players often agree tacitly or formally to count up the Japanese way. There could then be an issue in the very unlikely event of an anomalous position arising, but then the referee would give guidance (exactly as happens in pro events, incidentally). Go is a game, not a research project.

[willemien]

Did i really read:

Go is a game, not a research project.

or should i say

Go is many different things for different people

or something like

Go is a game, but what game

[Mef]

Aside from filling in dame (which techinically you are supposed to do anyway in Japanese scoring) the difference in score between AGA and Japanese scoring will be 1 point or less >95% of the time.

Realistically, switching from Japanese rules to AGA rules is very similar to driving a car from the United States across the border into Canada. All your speed limit signs change from miles per hour to kilometers per hour, so the numbers can be quite different (scoring style might change), but in practice you are driving basically the speed (the outcome is the same). If you were to more or less ignore the differences and drive the same as you would on comparable US roads, you will be fine except for very rare circumstances (likewise, playing as if it were Japanese rules instead of AGA, it will basically be the same, especially when the value of moves is >1 point).

In fact I think the English vs. Metric comparison works out really well as an analogy for rulesets, though to save space for those who don't want to see yet another ruleset rant I will shadow it:

Much like the Japanese rules, the English system makes little sense when taken outside of a historical context. Just look: 5280 feet to a mile? What on earth is a furlong anyway? 43,650 square feet to an acre? How could anyone find this useful?

Proponents of the metric system point out how simple it looks in comparison, after all, everything is in nice increments of 10! Not only that, but did you know they keep changing the English measurements? The foot they were using in North America in 1927 isn't the same as the one they use in 1983! That's not counting the fact that a survey foot is different from an international foot (nevermind the fact that all these differences usually work out to be about less than 1 inch per 10 miles). Sometimes I wonder how anyone is able to get anywhere traveling in feet. It might take someone years of study before they truly understand what they are measuring. Admittedly, it is nice that we have people who do study these things like surveyors, however even they argue about how things get measured!

Of course if you had to measure plots of land back before modern technology took hold, you might have done it with a surveying chain...in that case it might be useful mark off lengths of 10 chains (and call it a furlong). If you were marking off an area (like a plot for a city or a farm), you might take that furlong and then start measuring width with the same chain. For each chain of width, you would denote an acre. A furlong has the nice property of being exactly 1/8 of a mile. This means that if you have a 1 square mile parcel of land (8 furlongs x 8 furlongs), you can easily cut it in half (2 pieces of land measuring, 4 x 8). If you have to continue doing this you can keep cutting the pieces in half until you 64 total pieces of land that are 1 furlong x 1 furlong, and you will have never had to use a fraction or a number larger than 10 in a computation (not only that, but all of your final segments will be 10 acres!). If you were to try the same feat with a 1 square kilometer piece of land you would require larger numbers, fractions, or switching between 4 different units ( 1 kilometer/2 -> 5 hectometers/2 -> 25 decameters/2 -> 125 meters). It would appear the metric system is not devised to be practiced in one's head.

We also overlook the fact that the entire metric system of measurement is based measuring how far light in a vacuum will travel whilst simultaneously counting hyperfine transitions of a cesium atom (because We all keep that apparatus on hand to confirm the accuracy of our measurements...right? Clearly we should be teaching our children quantum mechanics prior to having them measure anything, how else could we expect them to understand?), instead of something simple the average width of a thumb (the basis for an inch) or length of a chain (66ft, or 1 cricket pitch if that's your game). So while the metric system might be nicer and cleaner for many technical calculations, for practical considerations, some find the "crazy" English system is more convenient because the numbers are cleaner. Realistically speaking, they both work virtually the same for 99% of what people do every day. Often one is easier just because it is what they have always done and it feels right.

I feel like this is the way a lot of people approach rulesets. The Japanese ruleset gets critcized as "too complex" because its minutiae are idiosyncratic and often historically related, yet many people use it for learning go and have no problems with it because they just play....you may just learn that a bent four is dead, much like a child "just learns" that a foot is 12 inches and there are 5280 feet in a mile. One's ability to play and enjoy the game is not crippled by not knowing the specifics. If you don't worry about it and just use it, it's not really a big deal. If you are ever in a situation where there is a dispute and these little differences matter, you can refer to an expert (For go a rules referee, for measurements a surveyor). AGA rules are perhaps a bit more thoughtout in a modern precision context, however they ultimately rely on a premise that is not practically measurable in a real situation (I would highly doubt that 99% of players in a tournament would be able to properly enforce situational superko in a non-trivial >5 move cycle without temporarily suspending the game or having outside help).

In practice neither of these drawbacks for either side really matter, because we get by using what we're used to and develop shortcuts for the parts that matter (2.54 cm = approx. 1 inch, and fill dame with pass stones converts Japanese to AGA), the Earth keeps spinning even though we ignore the small stuff. Somehow millions of people manage to learn and use both the English measurement system and the Japanese rulesets everyday and not only don't worry about it, but may consider it a significant inconvenience when someone tries to change them. Go figure.

I guess when all's said and done I'd rather just kick back, enjoy some go, and have a pint (or 473ml if that's your thing).

[topazg]

English vs Metric??

[amnal]

We also overlook the fact that the entire metric system of measurement is based measuring how far light in a vacuum will travel whilst simultaneously counting hyperfine transitions of a cesium atom (because We all keep that apparatus on hand to confirm the accuracy of our measurements...right? Clearly we should be teaching our children quantum mechanics prior to having them measure anything, how else could we expect them to understand?), instead of something simple the average width of a thumb (the basis for an inch) or length of a chain (66ft, or 1 cricket pitch if that's your game). So while the metric system might be nicer and cleaner for many technical calculations, for practical considerations, some find the "crazy" English system is more convenient because the numbers are cleaner. Realistically speaking, they both work virtually the same for 99% of what people do every day. Often one is easier just because it is what they have always done and it feels right.

This argument is absurd...

1) You make the unjustified implication that we all must personally be able to verify the values of units. I don't see why you would think this.
2) You make the nonsense statement that one cannot understand a system of units without having understanding of the method by which these units are derived in the first place. This is clearly not the case.
3) The 'average width of a thumb' thing makes little sense to me. It suffices in the short term, for basic tasks, but...well, there are horrendous problems with using that kind of measurement in the modern world. Who is measuring all these thumbs? What happens when the average width of them changes? If we keep the old value, how do we make sure we don't lose track of what it is? And if you keep an old value like that, it's arbitrary and unmeasurable (which you seem to think is a bad thing) any way, so you haven't gained anything. It is far more useful to have values that can be measured accurately at any time because they are tied in to fundamental universal constants.

[hyperpape]

I have played nine AGA tournaments, several of which officially used AGA rules. I have always counted in Japanese style after filling dame. I don't know if that's compatible with AGA rules or not. I asked my opponent if I needed to give a pass stone. Sometimes they had to ask someone else.

Usually there are several people asking what the rules are fifteen minutes before the tournament. At least some of them end up saying "whatever" and playing the way they feel comfortable.

[Mef]

This argument is absurd...

1) You make the unjustified implication that we all must personally be able to verify the values of fundamental constants. I don't see why you would think this.
2) You make the nonsense statement that one cannot understand a system of units without having understanding of the method by which these units are derived in the first place. This is clearly not the case.
3) The 'average width of a thumb' thing makes little sense to me. It suffices in the short term, for basic tasks, but...well, there are horrendous problems with using that kind of measurement in the modern world. Who is measuring all these thumbs? What happens when the average width of them changes? If we keep the old value, how do we make sure we don't lose track of what it is? And if you keep an old value like that, it's arbitrary and unmeasurable (which you seem to think is a bad thing) any way, so you haven't gained anything. It is far more useful to have values that can be measured accurately at any time because they are tied in to fundamental universal constants.

I fear you completely missed the point. Of course the argument is absurd, that's what I was trying to get at. I was taking the old tried and true arguments you see over rulesets and moving them into a different context. Personally, if I went back to the "rules of the metric system" I would never be able to find out how long a meter is. I would be unable to measure it. The strict definition of a meter to an average everyday person has no use. Of course in practice no one worries about these things, and when they do matter you have people who are familiar with the specifics you can rely on (which is the entire point I was getting at). It is all to common to hear the claim Japanese rules cannot be understood by a beginner and are therefore unusable. Things like moonshine ko, 5 points without capture, etc are brought up in this context...it is comparable to saying you can't measure something in feet because you don't understand NAD27 or you can't actually measure something using a meter before you know quantum mechanics (otherwise how can you know what a meter is?).

In reality, most of us can get by with most of what we do with rough approximations...likewise most of us can play go with our friends without worrying about whether we need 2, 3, 4, or 17 passes at the end of a game in order to properly confirm that it has ended.

[Chew Terr]

Good luck on your tournament! Just remember dame, give a stone when you pass and white must paSs last. Have a blast!