"J2003 not consistent": What you mean is that different remote environments can result in different local LD status. I agree that J2003 should be improved for the sake of better modelling intention of Japanese professional players.
Concerning specific examples, it is necessary to show that they would remain final positions to be relevant.
Japanese 1989 rules do not say something like bent4 is dead since ko fight is not allowed in confirmation but are independent of the specific shape (bent-4), allow some ko fight but rewrite the confirmation rules to restrict such a ko fight to hopefully make it ineffective.
J1989 intention logical and consistent? Uh, what a joke. First of all, the intention would have to be stated unequivocally.
Allow hypothetical play inside local-2 only? Maybe this solves things but needs exhaustive testing. It might be fine if all examples behave well but local-only play violates the spirit of global play in go.
J2003 problem
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RobertJasiek
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santo
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Re: J2003 problem
Are we 100% sure that Japanese pros would rule both the left and right parts in these examples as truly independent for ko analysis? Do we have a source, or is it speculation? My feeling is that indeed they would, but I would not be completely sure without an authoritative source. The position feels like a giant seki/semeai thing among many groups at the same time, where none of the groups has two eyes yet, thus it has some feel as something similar to "Life-and-Death Example 4", where many attacks can be made at the same time but you do not ignore the "other part" in the analysis but rather play the whole thing together. That one does not have a ko though, so it is less problematic.
Without a rule where a pass lifts "more than one" ko shape, how do you solve local moonshine life? (Which leads to infinite repetition without being able to capture under the more direct interpretation of the written 1989 pass for ko rule). There are other things like "1 two-stage-ko + 2 basic-kos seki", molasses ko, round robin kos and similar things that can all easily fail under different interpretations of the "pass for single ko" version.
To me it looks like "the Japanese way" actually is "global play where you can pass for a specific local-ko-region", so that you lift "all the kos in a specific region", regardless of the exact shape. That behaves almost always the same as J2003, unless you have a really complicated tangled mess of related ko's that look independent but are not really separated by completely independent live stones (like in this example).
This example by Jann for example is resolved under such a rule by understanding the left and right kos as different "local-ko-regions", and thus have independent passing for each. But passing for "all the kos in the locality" at the same time solves the complications created by the other weird kos, which do seem to require passing once to free "the whole shape" (or other complex ko rules).
Of course, the difficulty of such "intuitive" rule is to define what exactly a "local ko region" is
Without a rule where a pass lifts "more than one" ko shape, how do you solve local moonshine life? (Which leads to infinite repetition without being able to capture under the more direct interpretation of the written 1989 pass for ko rule). There are other things like "1 two-stage-ko + 2 basic-kos seki", molasses ko, round robin kos and similar things that can all easily fail under different interpretations of the "pass for single ko" version.
To me it looks like "the Japanese way" actually is "global play where you can pass for a specific local-ko-region", so that you lift "all the kos in a specific region", regardless of the exact shape. That behaves almost always the same as J2003, unless you have a really complicated tangled mess of related ko's that look independent but are not really separated by completely independent live stones (like in this example).
This example by Jann for example is resolved under such a rule by understanding the left and right kos as different "local-ko-regions", and thus have independent passing for each. But passing for "all the kos in the locality" at the same time solves the complications created by the other weird kos, which do seem to require passing once to free "the whole shape" (or other complex ko rules).
Of course, the difficulty of such "intuitive" rule is to define what exactly a "local ko region" is
Re: J2003 problem
What we know is old Japanese rules had bent4 independently dead by explicit rule, and J89 has almost the same because of the pass-for-ko rule. I also think passing for more than one ko simultaneously makes little sense conceptually or theoretically.santo wrote:Are we 100% sure that Japanese pros would rule both the left and right parts in these examples as truly independent for ko analysis? Do we have a source, or is it speculation?
If you mean the closed double ko loop, I think it has two possible explanations. It wouldn't be surprising if J89 pass-for-ko was intended like this: recapturing in a ko without passing for it is forbidden, but later recaptures in the same ko don't require further passes again.Without a rule where a pass lifts "more than one" ko shape, how do you solve local moonshine life?
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santo
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Re: J2003 problem
But that interpretation of passing for the ko "only once" does not handle both molasses ko (https://senseis.xmp.net/?MolassesKo) and the following "long double ko seki" at the same time (as far as I understand, both cases should be seki under Japanese rules):
If you understand passing-for-ko to mean each single ko-shape of marking specifically the two-intersections of the ko-stones, then you need to pass twice to free the two-stage-ko part of the seki, and this positions becomes seki. If you understand each "shape" like the two-stage-ko to be freed completely with a single ko pass, white dies instead.
For the molasses ko, it is the other way around: if you consider that you have to pass twice to completely free the two-stage ko, then one side is considered dead, while it is (anti)seki if a single pass frees the whole two-stage-ko shape. There is not time in these examples to "recapture the ko again later once it has become a normal-play-ko", so that rule does not change it.
These examples were discussed when creating the Katago rules, as the Katago rules use a version of the Japanese pass for ko rule for each specific pair of ko intersections and thus will consider one specific player to die in the molasses ko if left as is, creating a very small difference (there is a single recorded case of molasses ko in actual play, that happened in an amateur game).
The only way I see to handle both positions is that a pass actually acts like a "normal" play somewhere else and thus lifts all the related kos in the region. J2003 have a global ko pass doing precisely that, but then it seems that it can get some interference from the elusive "enable" rule, which is very hard to pinpoint exactly as to when a stone counts as enabled and when it does not. My feeling is that Japanese pros have an implicit notion of locality, and then consider each locality as "a single ko", even if it has 4 kos inside it like this example, it is "one ko" (one long double ko, say) on the board, and you pass for "it" specifically, to separate it from a bent4 in an opposite corner and such, but the whole shape is what you pass for.
If you understand passing-for-ko to mean each single ko-shape of marking specifically the two-intersections of the ko-stones, then you need to pass twice to free the two-stage-ko part of the seki, and this positions becomes seki. If you understand each "shape" like the two-stage-ko to be freed completely with a single ko pass, white dies instead.
For the molasses ko, it is the other way around: if you consider that you have to pass twice to completely free the two-stage ko, then one side is considered dead, while it is (anti)seki if a single pass frees the whole two-stage-ko shape. There is not time in these examples to "recapture the ko again later once it has become a normal-play-ko", so that rule does not change it.
These examples were discussed when creating the Katago rules, as the Katago rules use a version of the Japanese pass for ko rule for each specific pair of ko intersections and thus will consider one specific player to die in the molasses ko if left as is, creating a very small difference (there is a single recorded case of molasses ko in actual play, that happened in an amateur game).
The only way I see to handle both positions is that a pass actually acts like a "normal" play somewhere else and thus lifts all the related kos in the region. J2003 have a global ko pass doing precisely that, but then it seems that it can get some interference from the elusive "enable" rule, which is very hard to pinpoint exactly as to when a stone counts as enabled and when it does not. My feeling is that Japanese pros have an implicit notion of locality, and then consider each locality as "a single ko", even if it has 4 kos inside it like this example, it is "one ko" (one long double ko, say) on the board, and you pass for "it" specifically, to separate it from a bent4 in an opposite corner and such, but the whole shape is what you pass for.
Re: J2003 problem
No, I didn't mean like that. A ko recapture needs a previous pass for it, this is clearly stated in the rule, and is true for all kos individually, which the opponent took earlier. So no "shape" magic and single pass for all stages.santo wrote:If you understand each "shape" like the two-stage-ko to be freed completely with a single ko pass
A known unclear detail is whether a destroyed and later recreated ko mouth at the same intersection is still the same ko or a new ko. I am unaware of anything in J89 that would clarify this. But this needs an answer regardless of pass-once or pass-each-time interpretation.
About the molasses ko, iirc Davies was quoted saying in Japan it would be no result. I also think this is more reasonable (never safe to pass in response to the opponents pass).
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santo
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Re: J2003 problem
You mean that it is not safe to pass after the opponent pass in the molasses ko because if you do, then the game goes to scoring and life-and-death considerations rules your group death and the opponent's group alive? A resumption would not occur, as Japanese rules say that the opponent of the player asking for resumption starts, thus no player wants to resume (one player losses if they let the other start, while the other can restart just to prolong the game for no reason, as in any normal double ko, so it would also not lead to no-result).
That is very interesting, indeed. If the actual Japanese result of molasses ko is no result, then this is one less difference between Katago interpretation of the rules and the actual Japanese rules. I must say Katago rules did a really good job to extend the "hybrid" rules idea to have three different phases and use the Japanese pass-for-ko-rule (together with a special kind of "superko" rule for the special second phase, that prevents abusing the double ko seki). That contribution was key to have a "dumb-computer-player-proof" ruleset with Japanese rules consequences.
That is very interesting, indeed. If the actual Japanese result of molasses ko is no result, then this is one less difference between Katago interpretation of the rules and the actual Japanese rules. I must say Katago rules did a really good job to extend the "hybrid" rules idea to have three different phases and use the Japanese pass-for-ko-rule (together with a special kind of "superko" rule for the special second phase, that prevents abusing the double ko seki). That contribution was key to have a "dumb-computer-player-proof" ruleset with Japanese rules consequences.
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CDavis7M
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Re: J2003 problem
I think people are misinterpreting the Japanese Rules. The 1989 Japanese Rules Committee said they were going to find a rationale for past rulings and that's what they did. Consistent rulings were kept and inconsistent rulings were dismissed. The life and death rule requiring a pass is simply the rationale for how scoring works. It is a procedure that can be followed (as in the examples) but it is not a procedure that would be followed. The Japanese Rules Committee never said they were creating a procedure and the rules do not require a procedure. And the procedure, when it is shown in the examples, follows a particular style consistent with proving life and death (e.g., trying to kill rather then recreating the same position, etc.). From what I've read, the referee in a Japanese professional game would make a decision from the definitions in the rules.
Also, the Japanese Rules state the a ko should be specified. They also state that dame are filled to confirm life and death. The supposed issue with these kos is not actually an issue under the Japanese Rules. The "long double ko" is seki and molasses ko is dead. Though yes, if the players would not agree to end the game because of a molasses ko, then there would be no result.
The "destroyed and later recreated ko mount at the same intersection" is still the same ko. The rules define ko by the "shape." If stones are captured and then placed again in the same same then it is the same ko shape. We can't pretend that the players cannot recall the shape being there.
Going all the way back, the topic "J89's pass-for-ko: Misinterpreted in the Western Go World?" is a misinterpretation itself.
Also, the Japanese Rules state the a ko should be specified. They also state that dame are filled to confirm life and death. The supposed issue with these kos is not actually an issue under the Japanese Rules. The "long double ko" is seki and molasses ko is dead. Though yes, if the players would not agree to end the game because of a molasses ko, then there would be no result.
The "destroyed and later recreated ko mount at the same intersection" is still the same ko. The rules define ko by the "shape." If stones are captured and then placed again in the same same then it is the same ko shape. We can't pretend that the players cannot recall the shape being there.
Going all the way back, the topic "J89's pass-for-ko: Misinterpreted in the Western Go World?" is a misinterpretation itself.
Re: J2003 problem
No, I mean not safe to pass because that would be suicidal if normal play would continue (would depend on the stop and getting two moves in a row in case of a resumption).santo wrote:You mean that it is not safe to pass after the opponent pass in the molasses ko because if you do, then the game goes to scoring and life-and-death considerations rules your group death and the opponent's group alive?
This is a doubtful situation and it also involves the "both lose" clause, a rare case where J89 does have a logical problem. It is not clear when and how that clause should be invoked (if ever), since usually one side is happy either by scoring the stopped position as is or resuming (on the opponent's request) with him going first.
But imo the existence of this clause shows Japanese rules do not think it is ok to deliberately play a suicidal pass into a situation with an effective killing move left on the board. The stop on two passes is only a technical thing, the players' strategy should be the same whether the stop is on two passes, three passes - or on verbal agreement like in the old times.
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santo
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Re: J2003 problem
My understanding is that it is safe to pass under the Japanese resumption rule: "for whoever asks to resume, then the other player starts". Your opponent pass, you pass - you don't ask for resumption. So that way the game either goes to scoring directly, or it resumes and it is your turn - thus, your pass was safe, the opponent can at most make you play and go on, when you can play once more in the molasses ko and then be the one that passes first, etc.
But, also in addition to that, when using the 1989 "pass for single ko" version so that you must once for each stage of the two-stage-ko, then all of the stones of the player that passes last are deemed dead in life and death analysis, because no matter who starts the analysis, the player that has to retake that one will not get there in time and the opponent always kills everything.
Anyway, the conclusion ends up being the same, that passing is not safe, only that such "safety" depends on the final result according to the rules: if the rules had said seki, it seems to me like passing is safe and you can go for seki, which would then be the result. But the 1989 single-ko-passing-version rules death, not seki, and thus players will not pass, and thus it is no-result during the main game.
But, also in addition to that, when using the 1989 "pass for single ko" version so that you must once for each stage of the two-stage-ko, then all of the stones of the player that passes last are deemed dead in life and death analysis, because no matter who starts the analysis, the player that has to retake that one will not get there in time and the opponent always kills everything.
Anyway, the conclusion ends up being the same, that passing is not safe, only that such "safety" depends on the final result according to the rules: if the rules had said seki, it seems to me like passing is safe and you can go for seki, which would then be the result. But the 1989 single-ko-passing-version rules death, not seki, and thus players will not pass, and thus it is no-result during the main game.
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santo
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Re: J2003 problem
Ah, the "both players lose" clause is another beast altogether. I guess that might change things depending on exactly how you interpret it... I am simply ignoring that rule in my analysis.
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CDavis7M
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Re: J2003 problem
There is no logical problem in the "both lose" rule. Be sure to read the explanation under the rule. There's a second explanation from the Committee in their summary of the revisions.jann wrote:This is a doubtful situation and it also involves the "both lose" clause, a rare case where J89 does have a logical problem. It is not clear when and how that clause should be invoked (if ever), since usually one side is happy either by scoring the stopped position as is or resuming (on the opponent's request) with him going first.
"one side is happy either by scoring the stopped position as is or resuming (on the opponent's request) with him going first." There is a failure in the premise of one side being "happy." The player will not be happy unless they are happy to lose the game because their opponent is claiming victory. It's clear that both sides are claiming victory because otherwise the players would just resume the game to resolve it. If the supposedly happy player does not request the resumption of the game, thereby allowing their opponent to win, and they do not agree that they have lost the game, then both players lose because they do not agree and will not resume. This is the exact situation that this rules were intended to cover. It doesn't matter whether the position is actually scorable or what the score is. What matters is the agreement of the players. And of course these are rules for professional games overseen by a referee so a sad player cannot just force both players to lose.
It would be silly to pretend that the Japanese Rules Committee created a rule to address a situation that does not exist.
Re: J2003 problem
Victory is not just "claimed", is normally counted on points.CDavis7M wrote:unless they are happy to lose the game because their opponent is claiming victory.
The outcome is either decided by the score (this is the reality), by agreement (this would be hard to achieve logically, requiring the definition of special conditions on when a player is allowed to disagree), or by referee decision (again would need logical definitions of his ruling).It doesn't matter whether the position is actually scorable or what the score is. What matters is the agreement of the players. And of course these are rules for professional games overseen by a referee so a sad player cannot just force both players to lose.
I didn't say "both lose" is meaningless (it does show some intention of the rules, and that it's not ok to do risky/suicidal pass to force stop in molasses ko with killing move left on board for example). But from a logical viewpoint it does have a problem so cannot be easily applied. The rules only define how to score and doesn't define when a player is allowed to disagree ("effective move" is vague), especially without requesting resumption.