Bill: I think that Shuwa got it right. By the Japanese '89 Rules, at the end this position is worth nothing for either player. Therefore, assuming no ko threats, the player with the single stone (Black in this case) should play it beforehand, ending up with only 2 points instead of 3.
Like seki, this is an impasse. Each player would prefer to play second. But it is worth something to Black, by comparison with seki. Because it is an impasse, I think that it is unreasonable to force Black to play during regular play. It should be settled either by hypothetical play or by actual play in an encore. Since Black stands to gain by making a play (by comparison with seki), I think that it is reasonable to expect him to play first. But because Black plays one move more than White in the process, he should be given credit for that play, just as if he were required to make four plays to capture a single stone during an encore or hypothetical play. That justifies the ruling of 3 points without capturing.
Dave: I do not understand why you think it is unreasonable that Black play it out prior to the end of the game in order to get the 2 points. My understanding is that nothing is "forced", he can play and gain 2 points or not play and gain nothing in seki. The choice is Black's. I do not see any need to resort to hypothetical plays (much less special rules) at all.
Bill: What I am really objecting to is the determination of 0 points if left until after the suspension of play (as the current setup is). It is an impasse, yes. But it plainly favors Black.
Hypothetical play after suspension, along with the new definitions of life, death, and seki, makes this a seki if left after suspension of play. So there is no avoiding hypothetical play, here, under the current rules. And while the new definitions are not exactly special rules, since they apply uniformly, they do change the nature of the game. There is a cleverness and arbitrariness to them.
Dave: But it seems to me that the only way it is left unresolved is if Black tries to talk his way into 1 more free point instead of playing it out. I think the application of the seki rule is a good thing. In a normal seki (with negative impact for whoever plays first) both sides refuse to play and the result is zero (or whatever, depending on the rule set). Here there is a positive result for Black avaliable on the board but instead of playing, he tries to talk his way into an additional point.
Bill: I agree with the idea of playing out impasses. But they should be played out under the same conditions as playing out the capture of dead stones. (Which is also a kind of impasse.)
Dave: But my point is that I agree with the rules that say there is no impass here. There is only a choice. Black can play and get two points or not play and get none. If I understand the situation correctly, it is only by claiming that the definition of seki does not apply that one can assert that there is an impass. (Of course the chance that I do not understand the situation correctly can not be ignored :-)
Charles It's the difference between justice and equity, perhaps. It is perfectly just to ask players to play under a rule set that treats this as seki if left on the board at the end. There is an argument, that Bill makes, that equity might be better served by a ruling. Well, it is not clear this is a big practical issue.
Dave This just makes me even more puzzled. I do not see how you can claim that "justice" or "equity" in a game exists outside of the rules (at least that is what I think you mean). If the starting position meets the criteria for a seki, then play follows naturally to 2 points for Black. If instead the starting position meets the criteria for White's stones being dead, then Black would pick them up for 9 points without further play. Naturally White would then play first and the result would be 3 points for Black. One result or another has nothing to do with justice or equity. It only has to do with the rules you employ. A special ruling seems unnecessary unless you and the people you play with can not agree on the status of the starting position. However, in that case the special ruling seems completely arbitrary in choosing one result over the other. :-)
Charles You can't discuss equity within a fixed set of rules. For example, stalemate within chess is a draw - no question. One can (on other grounds) say this rule is 'wrong'; it is a hang-over from traditional ways of playing chess (such as the long-abandoned 'bare king' rule). So, this is not a formalistic question, which sees the rule set first and foremost. It happens, in this case, that the Shuwa ruling chimes with a CGT analysis (which is the main reason why Bill takes the line he does, I guess).
Dave All well and good I suppose but in the end doesn't that just require that we clarify the rules underlying the CGT analysis?
Charles I actually think there is quite a close analogy here, with the British law older usage: of having 'case law' on one side, and a set of ideas derived from systematic Roman law, with no status in the law of the land, in operation through the Chancery courts of equity. Well, I suppose this is getting off-topic.
Bill: To respond to Charles, it is not a clear practical issue. as you say. Practically, it makes hardly any difference, as such positions are quite rare.
It is, in a way, a happy accident that Shuwa's ruling agrees with the CGT analysis. It is too bad that we do not have a record of Shuwa's thinking on this. It would have helped with writing the rules later, I think.
As for myself, this is the kind of thinking I was using long before I had heard of CGT. I mean, compensating Black for the extra play when he plays first, not the difference game analysis. (Not that I was able to fully analyse this position. The ruling remained a puzzle to me.)
Dave, I think that the reason it is an impasse has little to do with the rules, except that it is not an impasse under area scoring. In this way it is more like dead stones inside territory, which is an impasse under territory scoring, but not area scoring, than like seki, which is an impasse under both kinds of scoring.
I suppose that Shuwa treated it like taking dead stones, which can be resolved through play if credit is given for any net plays required for their capture. It is also possible that he treated it as a kind of snapback, and judged it by the result when White plays first. (The value of a snapback is preserved when the snapback option is played. If it is played the other way, credit must be given for the extra stone played to preserve the value.)
My objection to the current rules about torazu sanmoku has to do with the definition of life and death.
If this position is left at the end of the game, the Black stones are dead because White may capture them playing first, and that's that. But the White stones are alive, even though Black, playing first, may capture them, because that capture enables White to play a new live stone (at , for instance).
That ruling is of little practical import, but it shows that the enabling rule for life is not really derived from the meaning of life. Its main value is to induce one player or other to finish certain situations before the end of the game.
Dave Is this the right example Bill?
I thought there is still an effective play here at the marked empty point. If Black captures four stones, there is another play at the marked White stone. I actually understood the Japanese rules to say that if this position remains unplayed at the end of the game both players lose! :-)
White has four points
connects at the marked point. White has 5 points, Black has 4 points.
I thought this was the type of position where the marked White stone was alive without further play because if Black captures, White can play another stone to recapture and that new stone will not be subject to recapture.
Bill: The effective play rule is somewhat peculiar. The reasoning is that, if the players find an effective play such that whoever requests resumption of the game would lose, and therefore the players cannot reach agreement about life and death (emphasis mine), then both lose. But the rules governing life and death at the end of the game may be quite clear about such a position, anyway. In fact, the official commentary includes hot examples that might have effective plays (such as this one), but tells us how to decide life and death for them, anyway. So just when the effective play rule would kick in is unclear. Are the players allowed to ignore the rules about how to determine life and death?
Anyway, one player or other might be ahead enough that the rule would not apply to this position, anyway. In that case, White would score 5 points locally. (Unless Black requested resumption, in which case White should take Black's stones.)
But my point still stands. If this position remains at the end of the game, the White stones are alive by the enabling rule and the Black stones are dead. The rules for determining life and death are pragmatic rather than principled. If they lead to absurd results, such as anti-sekis or sekis where both sides have two eyes, too bad.