Just a question. I am trying to start following pro tournaments and such, and am muddling my way through finding info online about all this. I know there has been much talk about Japanese dominance, and then the Korean take over, etc... etc....

I have two questions for those more familiar with the pro tourney landscape.

1) Do they switch scoring/rules for some of these tournaments? Or is it pretty much the host country scoring is what is used? I am really only aware of Japanese scoring with any familiarity, but I am curious as to how important it is to learn the different scoring methods, and how much it changes review of games.... and the strategy of games for that matter.

2) Also, do these changes in scoring/rules have any correlation to which nation might be dominant at any given tournament or time?

1) Yes, the host country rules apply. Japanese tournaments use Japanese. Korean tournaments use Korean. Chinese tournaments use Chinese. Ing tournaments use Ing...

2) For dominance no. There is a slight advantage you will get if you're used to area rules and your opponent is not.

Recent example.
https://gogameguru.com/an-younggils-pro ... yama-yuta/

Ing was indeed rich, but I don't think he had his own country.

The difference is generally negligible. There can be a slight effect on endgame strategy, e.g. when there is a last half-point ko and an odd number of neutral points or when there is the option to create an unbalanced seki, but for playing strength purposes your time is better spent on studying other things.

The difference affects ca. 1 point per game. A few hours of study suffice to gain this point. 1 point equals ca. 1/14 of an amateur rank and maybe 1/5 of a professional rank. With no other study, a dan can improve so quickly. Although the improvement is only 1 point, above beginner level it should be the first thing to study.

Since it is only 1 point, there is no national dominance due to being familiar with a different ruleset.

Isn't this lying with statistics?

Even if it does potentially affects 1 point per game:

1. It does not affect the actual result very often, and it is results that change a player's rank. You get no extra credit for winning by 100 points as opposed to 1 point. And style affects winning margins. Resignations make it otiose - a player may be involved in uncounted games more often than usual because of style.

2. A player who is unaware of the subtlety will still randomly get the right move right for the wrong reason 50% of the time, so the improvement (if any) would be 1/28.

3. It seems pretty evident that for all pros it was the last thing they studied, and some haven't even bothered yet. Since we know they are aware of the issue, they at least think there are other things are worthier of study.

And does it really take a few hours to grasp?

There is practically no link between knowledge of rulesets and playing strength: when I was in China we (1k/1d amateurs) taught our professionally ranked teachers about the different kinds of super ko rules.

When we are talking about the basic difference between area scoring and territory scoring, and not about things like Bent Four or points in seki or the group tax, or kos at the end of the game, then it rarely affects strategy. I am talking about final positions where the AGA (area) score is, say, 7 points for Black and the Korean (territory) score is 6 or 7 points for Black. Now let us look at an earlier position where best play by territory scoring leads to such a position. Then there may be other sequences that lead to the same area score, but to a different territory score.

Edit for correction: Is it ever the case, aside from the exceptions mentioned above, that best play by territory scoring will differ from best play by area scoring, and vice versa, i.e., that there is no line of play that is best under both kinds of scoring?

For instance, suppose that best play with Black to play under area scoring leads to a score of 7 points for Black, but only 6 points for Black under territory scoring, because Black gets the last dame; however, best play under territory scoring also leads to a score of 7 points for Black, but only 6 points for Black under area scoring, because there is a seki with an odd number of dame. But the second result cannot be, because with such a seki if the score for Black is 6 under area scoring, it cannot be 7 under territory scoring, it must be 5 or 6.

_________________
The Adkins Principle:
At some point, doesn't thinking have to go on?
— Winona Adkins

Visualize whirled peas.

Everything with love. Stay safe.

Of course not.

The 1 point does not come from the odd dame you mention but from the different value of a last basic endgame ko, which is worth 1 point under territory scoring but 2 or 4 points under area scoring. By experience, every second or third game has a basic endgame ko at the end. So the 1 or 3 points difference of the ko between the scoring systems, plus an empirical bit for an odd seki parity for the odd dame to matter, results in about 1 point difference, which is not necessarily nullified by area scoring parity but is part of the other yose.

The 1/14 point per amateur rank is explained by the 14 points miai value of an early opening move. Pro ranks are said to be almost 1/3 of an amateur rank apart, thus the ca. 1/5 of a pro rank.



See above. Your assumptions are wrong that it would only be about the odd dame.



1) It is their judgement mistake.

2) Of course, the rank effect is relevant only in international tournaments with a different ruleset than the national ruleset. This can also explain why they neglect to study it earlier.



Do you need more to understand the introductory chapters of my paper?
http://home.snafu.de/jasiek/kodame.pdf
For a pro familiar with area scoring, learning territory scoring strategy of ko and dame endgames takes only a few minutes. Maybe only a few seconds.

The few hours are an upper bound for the serious learner. (Learning also the value formulae would take longer.)

Understanding teire and ko strategy is more advanced but the extra benefit in points is small on average. My paper covers the regular, frequent cases without teire.

So, since your judgement is better than the judgement of professional players, why haven't you won any international titles yet?

_________________
“Discussion is an exchange of knowledge; argument an exchange of ignorance.” ― Robert Quillen

Robert just expressed an opinion. I don't think winning an international title is the requirement to voice an opinion on these forums (even if Robert tends to phrase it as a fact rather than an opinion).

Robert, do you not think that a pro player would be able to work out the best strategy in-game, even if they are not previously familiar with it? I would have thought that in practice, the principles/strategies are simpler than your lengthy paper implies.

tiger314, my statement about judgement refers to only the ko and dame endgames - not to playing skill at international pro tournaments in general.

quantumf, working out area scoring strategy for ko-dame endgames requires a basic strategic understanding of late endgame area counting (i.e., the idea that territory counting does not necessarily assess the right area counts), the conceptual discovery of dame ko fights with dame as ko threats because dame are valuable (surprise!), a correct judgement of ko and dame ensembles (a ko is not 4 points per se because the opponent might get a dame as partial compensation) and the right conclusion of possibly delaying a ko until after the dame filling. Although not impossible, I think that most (pro) players never having read about any of these aspects would hardly discover them during one, or a few, of his games.

Mostly likely, a pro would review his games afterwards, notice the "strange" score, find out an explanation for it and then, if he is bright, already consider some of the aforementioned aspects. However, unless, a dame ko fight was played against him in his first game, it is still quite a mental achievement to rediscover it, as I can tell by my experience. Despite Bill's recurring explanations of miai counting and ko / dame ensembles under area scoring, I played a couple of years on KGS with area scoring until I rediscovered dame ko fights for myself. Thus, IMO, a pro can quickly learn about a 2 points ko but not every pro would quickly find the 4 points case, which occurs only once every ca. 10 or 20 games if both players are aware of it.

The ko and dame effect.

1) Suppose that White takes a ko, Black fills a dame, and then White fills the ko, at which point there are no dame left. Then, although Black got the last dame, the result is the same under area scoring than under territory scoring. This is like White getting the last dame.

2) Suppose that White takes a ko, there are no dame so Black passes, and then White fills the ko. In this case White has played one more stone than Black, so that he gets one more point under area scoring than under territory scoring. That can affect the strategy.

For instance, suppose that with that sequence of play Black gets 5 points by area scoring, 6 points by territory scoring. But there is another sequence by which Black gets 5 points by territory scoring, 6 points by area scoring, because there is a seki with an odd number of dame. The combination of the ko fight without dame and the change in parity can yield a situation where there is no line of play that is best under both scoring methods.

_________________
The Adkins Principle:
At some point, doesn't thinking have to go on?
— Winona Adkins

Visualize whirled peas.

Everything with love. Stay safe.

In fact, we have a famous example in which the players worked out the outcome of a ko fight that outlasted the dame, the rules dispute between Go Seigen and Takagawa. They did not play the ko fight out. The Nihon Kiin rules at the time (and now) would have required the ko to be filled, yielding the current Japanese score, but the game was not played under Nihon Kiin auspices, and the players had not agreed on the rules beforehand.

The problem for Japanese players has not been the inability to read out the ko fights, it has been overlooking the fact that the difference between the area score and the territory score could be two points in favor of Black instead of one point, or one point in favor of White instead of even. Even if you sort of know that, under the stress of byoyomi you could easily forget to make the unfamiliar adjustment.

_________________
The Adkins Principle:
At some point, doesn't thinking have to go on?
— Winona Adkins

Visualize whirled peas.

Everything with love. Stay safe.

Maybe I am missing something obvious here, but why cannot a player unfamiliar with all the theory of area scoring just compare his area after a certain move and after his opponent's countermove and do the usual sente-gote movevalue endgame analysis?

_________________
“Discussion is an exchange of knowledge; argument an exchange of ignorance.” ― Robert Quillen

This is a good start, especially with the additional abstraction to count only newly gained live stones - not all life stones when this would be an overkill.

A player could also count all stones in a certain space. For example in a 4*5 rectangle. E.g. one sequence result area being: B 12 W 8, the other sequence result area: B 10 W 10, difference being 4 or 2 points depending on whether the evaluation is done in moku or zi.

_________________
“Discussion is an exchange of knowledge; argument an exchange of ignorance.” ― Robert Quillen

Sometimes that is good. But more often endgame analysis is easier using territory counting. In fact, every Chinese pro that I am aware of uses territory counting to evaluate endgame plays, as a rule. (Not that they can't switch. )

_________________
The Adkins Principle:
At some point, doesn't thinking have to go on?
— Winona Adkins

Visualize whirled peas.

Everything with love. Stay safe.

Nobody else has mentioned it so I will, but in this year's Super Meijin, Japanese fans watching the final game thought Iyama had won by 0.5. But they had been misled by the fact that there was a seki on the board with a (fillable) point inside, which they had ignored under Japanese rules but which counted for Chen under the Chinese rules in force. Some of them were doubly misled because the broadcast showed komi as 7.5 (as is fairly common in Chinese sgfs) instead of 3.75, and so assumed this meant Japanese rules applied. To add to the mix, Chen got the last dame as Black.

I have seen nothing to suggest Iyama was confused.

It was mentioned in Shukan Go that Iyama found out quickly afterwards, but made a mistake in byoyomi handling the situation.