As I said, a molasses ko is quite hot. Unless either player makes a sufficiently large threat, the game is likely to end in resignation when one player's only legal play on the board is to put one of his own groups into atari. Effectively, on the board outside the molasses ko, the game becomes one of no pass go.

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

Visualize whirled peas.

Everything with love. Stay safe.

How do you define a go anomaly? The Japanese 1949 rules required single kos to be filled or otherwise resolved, but Honinbo Shusai had disagreed, and Go Seigen still did. The question came up in a game between him and Takagawa, which Go Seigen had not agreed would be played under Nihon Kiin rules. An anomaly has arisen under the J89 rules, because of their redefinition of seki. Correct play appears to be for the players to leave groups with two eyes as seki. Ikeda warns against chasing anomalies. But Ing ended up chasing anomalies his whole life.



Before the 20th century go games ended by agreement. For some reason modern rulesmakers wanted to end play by passes, even though a player might pass without wishing to end play, because she wanted to take a ko. If you allow a pass to lift a ko ban, then that pass cannot be used in itself to end play, because it requires play to continue in order for it to be possible to take the ko. You can get around that with my rule, which stops play when the same player makes a second pass in the same whole board position. That usually means that three consecutive passes end play. Ing got around it with a four pass rule. Having different types of passes is another possibility.

For territory scoring the natural place to end play is at temperature 0, where the hottest play gains no points. This, OC, is the dame stage. However, questions may arise about unresolved kos, the life and death of stones, and standoffs such as Three Points Without Capturing and Bent Four in the Corner. All such questions may be addressed in an encore played at temperature -1, where placing a stone on the board costs a point. But, as Ing discovered, even play at territory temperature -1 can still present difficult questions when an unresolved ko remains on the board. But in any event, if you have play stop by passes at temperature 0 and then have play end by passes at temperature -1, the two kinds of passes are different. The J89 rules elect to stop play at temperature 0 and use hypothetical play after that. Hypothetical passes are different from actual passes.

You may be interested in a different approach which uses hypothetical play but no pass for ko rule. It makes use of Berlekamp's komaster idea. It is still a work in progress. See https://lifein19x19.com/viewtopic.php?f=45&t=17091

BTW, I saw a Korean rule set online some years ago, translated into English. I found it quite difficult to understand. I cannot find an English tranlation of the new rule set online. My impression now is that the older rule set may have allowed a player with enough ko threats to claim a point in a ko that was unresolved when the last dame was played. Do you know? Thanks.

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

Visualize whirled peas.

Everything with love. Stay safe.

I agree on superko anomalies, but those rulesets have deeper problem: they cannot even attempt to describe the game as it is / was played in practice (triple ko draws). Your rules seem to use a similar conditional n-fold repetition rule I suggested. This, I think, leaves a simple ko area scoring ruleset in a situation territory rules start at: no problems until after the first stop (or dispute).

How should the rules work after that stop (moonshine etc) is quite subjective and depends on one's objectives. Simplicity-wise the hack mentioned earlier (superko only after first stop) seems like an alternative, both for human and bot rules.

I don't think this is a real problem because resumption should always be possible (even if there is a potential question about the order).

How do you prevent infinite resumption with a double ko seki?

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

Visualize whirled peas.

Everything with love. Stay safe.

OC there must be some limit on the number of resumptions (even without double ko seki), but I see this as something that could be left to tournament rules. It can be a server dependent hard limit or something else, doesn't really matter as long as it's not too strict. Not the same kind of actual problem as sending-two-returning-one for example, which really needs some minimal change to ko rules to allow the game to reach stop.

I think you are assuming a kind of superko rule is in effect. Using SSK, the game will likely end leaving the local shape as a seki. Using PSK, ugly(?) no pass go will result.

However, Japanese, Korean and Chinese rules do not adopt any superko rules. They don't mind the same shape repeats. Some of the whole board repetition (triple ko, quadruple ko, etc.) results in a draw, some (sending-two-returning-one, double ko trick, separated moonshine life, etc.) are not. For combined moonshine life, Japanese rule thinks its dead, but Korean and Chinese rules say a draw may result. Their real problem is to present a clear algorithm distinguishing the two cases.

What I tried to say was that... for the standard molasses ko shape, pros think it is "the type of repetition that a draw is allowed".

_________________
Jaeup Kim
Professor in Physics, Ulsan National Institute of Science and Technology, Korea
Author of the Book "Understanding the Rules of Baduk", available at https://home.unist.ac.kr/professor/jukim/bbs/board.php?bo_table=notice&wr_id=5

This was the first research project I worked on as a rule theoretician, and I soon realized that it is impossible. Anomaly is something that most strong players do not want the rule to allow, but it is certainly a subjective concept. However, when the subjective thoughts are gathered to form a certain opinion, it is not something one can easily ignore. If, let's say, a rule is carelessly written so that sending-two-returning-one results in a draw, 99% of the pros will look at it and say "I can't accept it. Change the rule!".

Maybe for one or two shapes, we can find a clever algorithm to distinguish anomaly. (For the sending-two-returning-one, we may count the captured prisoner difference.) What I am saying is that I cannot imagine a few sentences defining all anomalies, because anomaly is a subjective concept.

If there exists a clear definition of a go anomaly so that when a sequence (Q16, D4, ...) is given a program beeps that "78th move initiates anomaly!", it is so easy to remove the anomaly from the rule. You simply write down the rule you want, and add one sentence "the player who initiates an anomaly (defined by the following algorithm) forfeits."


R. Jasiek uploaded the translated version in his homepage. ( http://home.snafu.de/jasiek/k2016.html )
The old Korean rule (assuming you are talking about 1992 rule) allows the player to leave an n-move apporach ko, but not a direct ko. The conclusion is the same for the current rule, but the principle has changed.

_________________
Jaeup Kim
Professor in Physics, Ulsan National Institute of Science and Technology, Korea
Author of the Book "Understanding the Rules of Baduk", available at https://home.unist.ac.kr/professor/jukim/bbs/board.php?bo_table=notice&wr_id=5

In my ruleset, the game never temporarily stops. (I have this luxury because it is an area scoring rule.) All anomaly attacks will ultimately be penalized by sequence analysis. (The analysis is easy for a computer program). Any long period repetition which are not penalized ends the game with a draw.

_________________
Jaeup Kim
Professor in Physics, Ulsan National Institute of Science and Technology, Korea
Author of the Book "Understanding the Rules of Baduk", available at https://home.unist.ac.kr/professor/jukim/bbs/board.php?bo_table=notice&wr_id=5

This is why I suggested dividing the game before and after first stop (like is the case naturally with Japanese or Korean rules). With a good repetition rule that also handles unbalanced cycles, the answer is simpler: any (balanced) repetition before first stop is a real draw, the rest is much easier handled in dispute/resumption phases. The point here is the simplicity gained for the first phase (which is usually the only phase) - most players won't learn complicated rule additions anyway.

BTW, allowing connected moonshine to live gives the game a weird turn where one side cannot really lose anymore.

For some players dead stone agreement may imply a kind of stopped state, though you are right this is not absolutely necessary. But I also feel the kind of sequence analysis you use - however interesting theoretically - may not form attractive rules for practical human play. I can imagine even just reaching adoption of conditional n-fold repetition rule would not be easy.

It is not much easier in my experience. Yes, if repetition occurs after the first phase, there is a high chance that someone is just trolling. But who is to blame? In a rule where a connected moonshine life is allowed to live, the repetition after the first phase may still result in a draw, and no one is to blame. The purpose of the sequence analysis to identify who is to blame and penalized.

I don't understand the exact situation you are talking about. For me, whichever decision (draw or dead) is acceptable for the connected moonshine life. The problem is that the sequence of repetition for connected moonshine life and separated moonshine life are virtually the same, which means a logical rule allowing the life of a connected moonshine life is likely to allow a separated one to live, and most people will hate to see it happening. In my ruleset, the player who does not give up the connected moonshine life is penalized.

For players who are playing normally, they wouldn't even notice that a sequence analyzer is included in the rule. Only when some weird situation occurs or someone is really trolling, it's the time a program or referee to come up and try sequence analysis. The defender does not need to worry about the sequence analyzer, because he will never be penalized by it. Once the troll learns that all wicked attacks are penalized by the opponent's normal play, no one will try it any more.

Anyway, most games I play are online games, and I don't mind a sequence analyzer program working background while I am playing, as long as it is working properly.

_________________
Jaeup Kim
Professor in Physics, Ulsan National Institute of Science and Technology, Korea
Author of the Book "Understanding the Rules of Baduk", available at https://home.unist.ac.kr/professor/jukim/bbs/board.php?bo_table=notice&wr_id=5

Correct about my assumption. Sorry, I was relying upon memory from the 1990s. People say that situational superko produces a different result than positional superko. I don't think so. See SGF file.



The first player to pass can be made to violate both a positional and situational superko.




Right about Japanese and Korean rules. Chinese rules have a positional superko "in theory", but allow the organizers or authorities to have different rules, which I gather they usually do.

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

Visualize whirled peas.

Everything with love. Stay safe.

For me the very reason to separate the main phase from resumption phases is to restrict special ko rules (necessary for moonshine) to those later phases. So a player who wanted to force repetition but forgot (?) to do so and passed instead may not be able later, whether a simple hack like superko or some more sophisticated ko pass rules are used there. This is the price of having the first phase (the main game) free from extra rules, and to ensure nothing unexpected will rob the players from their legal moves in it. Basically, to allow the main game to progress in its natural way.

I meant a connected moonshine is not automatically draw, even if allowed, the player who can repeat may choose to play for a win (letting it live), and only "cash out his draw option" if that doesn't work out. This issue does not arise if it can be killed in dispute phase. BTW there are logical rules that can differentiate the two cases, for example, explicit localization and control (Pauli) - even though I prefer identical handling (cycle/ko behaviour over locality).

This is still quite different from other board games, where the players themselves have no problem applying the rules (which may even be necessary for gaining wide adoption).

I wonder if there were ever any serious games (under Chinese rules) where triple ko was NOT treated as draw? I always thought this is unversally accepted in all three main go playing countries (and their histories), with maybe even casual players being aware of this rare case.

I keep saying "anomaly" is a subjective term, so if you think it is an anomaly, I can't say it is wrong. However, I just want to point out that most people does not think having a choice of draw is not an anomaly. In a game under Chinese rule where a bent-four-in-the-corner and a double ko seki shape is left, one player may have an irresistible choice of making a draw. It is up to the player's calculation, and he can simply try scoring and win the game.

As far as I know, the answer is no. A triple ko is a de fecto draw in China, whatever the rule text says. (These kind of things make the life of rule theoreticians much harder. You may have years of rule study, but a newbie pro may still know some practical application of the rule you never learned from texts.)

_________________
Jaeup Kim
Professor in Physics, Ulsan National Institute of Science and Technology, Korea
Author of the Book "Understanding the Rules of Baduk", available at https://home.unist.ac.kr/professor/jukim/bbs/board.php?bo_table=notice&wr_id=5

I am a little bit unsure if we are talking of the same subject. Just to make life easier, let us assume that White move 0 was at (1,C), and all the upper sides are played so that no more meaningful(in a traditional sense) plays are left other than the molasses ko.

Under every rule, Black 1 is necessary unless Black gives up one's group.

In PSK, if Black chooses to pass as 5, Black's move 9 will be prohibited. Thus Black must jump into the pass fight as 5, where the first passer loses the game.

In SSK, Black can pass as 5. Black's move 9 is allowed, and White's 10 is a pass. Now Black passes as 11. (Maybe this is something you missed. White cannot play at (1,E) as 12.) In AGA rule, both players will pass one more time and the game ends leaving a molasses ko seki. (Any other choices are either prohibited or results in one's loss.)

_________________
Jaeup Kim
Professor in Physics, Ulsan National Institute of Science and Technology, Korea
Author of the Book "Understanding the Rules of Baduk", available at https://home.unist.ac.kr/professor/jukim/bbs/board.php?bo_table=notice&wr_id=5

Not sure if this applies to that situation, but Sensei's further distinguishes between situational superko and natural situational superko. I find this interesting:



NSSK sounds the most elegant to me.

Thanks.

SSK plus two passes to stop play plus preservation of the superko ban in the resumption or encore ends play in position A. Whether to call that a seki or not is another question.

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

Visualize whirled peas.

Everything with love. Stay safe.

No, I wouldn't go as far as calling this an anomaly (which I'd only say on clearly wrong rulings). It is just a suspicious situation that would not otherwise arise. The difference to bent4+dks is that bent4 is a known and accepted not-always-dead and play-out shape (area rules, unremovable threats). With moonshine life, the only reason one would think of it as alive (in the connected case only) is a side effect of explicit localization - which in itself is an unnecessary and ad-hoc rule invention in my opinion. OC there is also the case where actual capture is necessary during the main game already, for nearby fights - but in that case it is not moonshine life anymore!

I also agree on subjectivity - which I think is another advantage of dividing main phase <> resumptions: all subjectivity is pushed to dispute phases, leaving the main game clean and unquestionable.

BTW, about molasses ko: the fact that in almost all such superko analyses there are some oversights can form a rather strong argument against superko (at least its use in the main game).

Yes, it is somewhat different from a normal seki. In some sense, the whole board is frozen and players just can't touch anywhere on the board. A Whole board repetition with period 5 is another example that SSK and PSK are working differently. https://senseis.xmp.net/?SendingThreeReturningTwo

Another important lesson is this. Lifting ko ban or superko ban after a pass (or other reasons like resumption of game, change of phase and etc.) can be dangerous. In my exeprience, efforts to remove one anomaly usually results in another unexpected anomaly.

_________________
Jaeup Kim
Professor in Physics, Ulsan National Institute of Science and Technology, Korea
Author of the Book "Understanding the Rules of Baduk", available at https://home.unist.ac.kr/professor/jukim/bbs/board.php?bo_table=notice&wr_id=5

Well, the molasses ko has an odd repetition only if you count a pass as a play. The game tree of the molasses ko has no passes. AFAIK, Ing was the one who introduced the idea of a pass as a play. Otherwise, relinquishing the right to play was a typical locution.



Well, the main difference between the framers of the Japanese 1949 rules and Honinbo Shusai and Go Seigen was the question of whether there should be a final ko ban in effect. Shusai, Go Seigen, John Tromp and others say yes. The Nihon Kiin, Ing, and others say no. Yasunaga's "Draft Constitution" said no.


( http://park6.wakwak.com/~igo/igorule/yasunaga.html )

That explains his 3 "pass" rule. The first pass may have been forced by the superko rule, but the second and third passes are unencumbered, and may be taken as indicating a willingness to stop play.



I don't think that the question here is one of anomalies, but of what it means for a position to be final. If the rules embody the preferred definition, whatever it is, then let the chips fall where they may.

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

Visualize whirled peas.

Everything with love. Stay safe.

I think the latter statement has little to do with the former. IMO in all cases where passes lifting bans - supposedly - leads to problems, it is actually some other, poorly formed rule producing the anomaly, with passes only uncovering it. With normal ko, bans are temporal not positional, so a pass works naturally (unlikely to produce unexpected things by itself). Not being able to recognise this is the very source of some superko anomalies.