If your model is so good, where are your rules?

There can be strong doubts whether the writers of the official commentary really understood their examples 16-18. They can have more sequences than are apparent at a glance.

Fake dead stones behind a snapback are stones whose status is unexpected due to the presence of the snapback.

What are your definitions for "can (force) capture", "cannot (force) capture", "alive", "dead"?

Complexity: maybe. There is too little research about it.

The rules are in my head and parts of it divided on different papers. If you're interested I could (mainly a matter of motivation) write them down - I need to search the papers and also check which versions are the correct ones as I changed a lot of things during the creation (and it's over 1 year ago). Or maybe it would be more efficient to write them new...
I would be interested to get some feedback, too, because I'd like to know wether they are really good or a failure. (Sometimes when I make a thinking mistake and miss the right point to notice it, it becomes very hard to notice it later on because I repeat the same mistake without thinking about.)


For the examples 16-18 it's quite obviously that they overlooked the cycles containing ko-passes, but (for me) it's very obviously that these cycles are not allowed. Also there are some cycles without ko-passes that can also cause simular problems and need to be solved, too. My method here covers both in the same way.

I don't (explicitly) define "force" or "hypothetical-sequence" as you did in j2003.
Instead my rules uses exactly one playout for each string. Every playout ends in finite moves. Depending on the end position of the playout the string gets the state of either dead or alive. (For cycles it's a bit more complicated because then the moves played are also relevant).
Also the result of a playout doesn't affect the result of other playouts, so the order is not relevant.

OTOH in j2003 the result of capturable-1 also effects captuable-2, what is more complex.

Another advantage with my playout concept is that I designed it to give a "natural strategy". This means it's never bad to kill what you can / live where you can. In j2003 you was forced to define "hypothetical sequence" because there are cases where if you would make a playout it could be good to let capture stones that are capturable-1 or uncapturable (or not capture stones that are dead).

IMX, such a booboo is more likely. (And I try hard to come up with interpretations that make sense. I considered that "sum" might be better translated as "total", for instance.)

Unfortunately, we do not have the original Korean, but here is the relevant context.



Your suggestion, 'the number of liberties of contiguous stones is the total number of liberties of the stones as a group.', is tautologous, given that they have defined contiguous group in the preceding sentence. Not that people do not state tautologies, but to do so here would violate the pragmatic rule against telling us what we obviously know. It would not only be, as Robert points out, superfluous, but a waste of the reader's time.

Leave out "number" and change "sum" to "total" (or maybe "totality") and we get "The liberties of a contiguous group are the total of the liberties of each stone in the group." That is something that we could deduce, but it is not just a tautology. I think that "total" allows us not to count the same liberty twice. The problem arises when we talk about the number of liberties. That is one kind of mistake that non-mathematicians make, assuming that numbers add up when they don't. I am afraid that "number" is in the original Korean.

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asura, of course, I am interested in your rules.

Why do you call it obvious that cycles including ko-passes should not be allowed?

Using one finite playout (per string) is much nicer for application, of course. However, it contradicts the spirit of official Japanese rules, which seek perfection in omniscient play. OTOH, if the players make correct hypothetical choices during the one analysis sequence per string (and possibly per status), then "force" is not needed. You can then (roughly) define that a string is alive if a same-coloured permanent-stone / at least one same-coloured stone is on one of its intersections at the end of the analysis sequence for the string. Straightforward; this should work. I would have to think a bit why / whether local-2 could become superfluous in this manner. But anyway, somehow in this manner one gets pretty / possibly extremely well behaving Japanese model rules. Only a model, because THE PLAYERS MAY MAKE HYPOTHETICAL-STRATEGIC MISTAKES during every analysis sequence! (If you want to prohibit such mistakes, then you need "force" again.)

For cycles, simply end an analysis sequence on a move recreating a position / an earlier position during this analysis sequence.

I do not understand yet what you mean by "natural strategy".

I call it's obviously because the given result in the commentary. Also there can be cycles with ko-passes where without ko-passes no cycle would be.
If this is not intended, why did you change the ko-pass rule in j2003 to get this results?

I know that a playout is not exactly the same spirit as j1989, but I wouldn't call it contradicting it. Actually I could simply add your definitions about "hypo-sequence" and "force". And applying the playout-rule can be done just by talking. However this is only a theoretical difference, because under j2003 in practise you only look at some variations and can make mistakes, too, no matter what the rules say (Actually one could say you "hide" this fact with your rules.)

(roughly) defining that a string is alive if a same-coloured permanent-stone / at least one same-coloured stone is on one of its intersections at the end of the analysis sequence for the string is NOT enough for the strings that are capturable-2 under j2003. That's where my "local" definitions comes in play.

In my model I use two different types of cycles : fighting-cycle and disturbing-cycle (well and simply defined what is what so it's a bit more complicated, but that is no problem and only matters in rare cases. As a benefit it's not needed to lift all ko-bans with a ko-pass.


With "natural strategy" I mean that for ALL strings it is always better or equal for the attacker to kill the string and always better or equal for the defender to live with the string.
This may sound trivial, but it is not.


edit: Now after saying how good (hopefully) my rules are it seems I have no choice but need to write them down because else it would look more stupid than a total failure would look
The week arround Christmas I have no PC and no guitar, so I plan to do it then. Motivation and lazyness might change it though...

Allowing cycles with ko-passes, the intended outcomes are confirmed. (IIRC, cycles with ko-passes are not a problem for examples 16-18.)

The J1989 ko-pass rule needs to be changed, because it is incomplete. See the flaws

022 o 7.2 ambiguous scope of application of the ko-pass rule
023 o 7.2 ambiguous difference between pass and ko-pass
024 o 7.2 unspecified successions of pass / ko-pass
025 o 7.2 ambiguous consequences of alternating sequence on ko-passes
026 o 7.2 unspecified presupposition for early ko-pass
027 o 7.2 unspecified validity of double ko-pass
028 o 7.2 ambiguous "temporarily disappearing" ko

http://home.snafu.de/jasiek/j2003com.ht ... e1989Rules

More importantly, I changed the J1989 ko-pass rule, because its application contradicts the intention of J1989! I forgot the relevant examples, but presumably you find them here:

http://home.snafu.de/jasiek/j1989c.html

J2003 is not designed for incomplete application in practice, but for complete application in theory, even if this should require more storage than the universe offers;)

Can you please show examples
- of capturable-2 to demonstrate why your rules still need some locality concept,
- fighting cycle according to your definition,
- disturbing cycle according to your definition,
- how not all bans need to be lifted?

(Around Xmas, if you like.)

With "cycle with ko-passes" I mean a cycle that contains one ore more ko-passes. But it's NOT required to contain only ko-passes.

As far as I can see this is the main problem with the ko rules in j1989 and the (one and only ? ) reason to introduce the ko-pass for all kos from both players.

It's some time ago that I read the commentary to j2003 and IIRC everything that you wrote seems to indicate this, too. (I remember it because I was not happy with the ko-pass for all kos instead for a specific ko from the very first time and payed attention to this)

With a strict application of j1989 rule all the examples 16-18 wouldn't work.


- there are different classes of what is capturable-2 in j2003. For some classes I could avoid "local". I need it e.g. in Life-and-Death Example 2 from the official commentary.

- fighting / disturbing cycle is a bit of a word play related to ING rules:)
(a little bit related) but here it simply means: a cycle is a fighting cycle if it contains one ore more intersection of the string thats state is in question,

- else it is a disturbing cycle.
(When the game is already over the ING rules works much more easy

- as I said above the problem with the ko-pass in j1989 is when they make endless cycles possible. The most flaws you have listed are that they are not very clear formulated. But while this can be easyly fixed the cycles are a severe problem.

The way you did in j2003 solves this problem, but why should it be generally nessecary to lift all ko-bans with a ko-pass in any Japanese style rule?


If there is another reason why you made the ko-pass lifting all ko-bans I would be really intered in!

Well, of course, nothing is necessary. However, if you believe that it is desirable to end play in an unambiguously scorable position, then that score should be the same regardless of which player plays first, with no ko ban. Thus, one of the first proposals for written Japanese go rules, Yasunaga's Go Constitution, had a three pass rule for ending play. It did not explicitly talk about lifting ko bans, but otherwise why the need for the third pass? My first set of rules ended play with the second pass by the same player in the same position, which normally would be a third pass rule. I also explicitly had passes lift ko bans.

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

Visualize whirled peas.

Everything with love. Stay safe.

I did not mean passes during the game but during the determination of life and death. The rule in j1989 is that one ko-pass only lifts one specific ko-ban, but in j2003 one ko-pass lifts all ko-bans.

I don't know Yasunaga's Go Constitution, but i beleave the 3 passes are meant to avoid someone passing after the opponent has passed (e.g. because there are no neutral points to play) with an open ko. If so it wouldn't make sense if the passes don't lift a ko ban - here it would give the result whether a pass lifts one ko ban or all.

The J89 pass for ko rule is an attempt to localize the effects of kos, but in the end does not do so for multiple kos. If you then abandon the idea that multiple kos are independent, you get pass lifting all ko bans. In my Japanese style rules I started out having pass lift all ko bans, but got some results that seemed far from the spirit of the J89 rules. So I went back to a pass for ko rule and adopted a different rule to handle global effects, the once only rule. (A player can take a ko only once in a certain position of the whole board.)

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

Visualize whirled peas.

Everything with love. Stay safe.

As Martin Stiassny has pointed out elsewhere
http://www.dgob.de/yabbse/index.php?topic=5181.0
"Asian Games" were in 2010 and will again be in 2014 (then probably without go). "Asian Indoor [...] Games", as they occurred in Korea in July 2013, are a different series of events. IOW, this difference must be kept in mind when you see my abbreviating title "Asian Games 2013 Rules". Abbreviations are dangerous;)

asura, as I said, there are examples why ko-pass-for-one-particular-ko does not work as intended. That's why generic-ko-pass is needed. (No time to look up the examples ATM.) EDIT: http://home.snafu.de/jasiek/j1989c.html Example 0001 is such an example, although not the simplest.

Instead of calling your cycles "fighting/disturbing", I suggest "local"/"non-local" or something similar.

J1989 allow infinite cycles regardless of the ko-pass rule! See official example II.24+25: the ko stones of a double ko seki are declared "dead". This makes sense only if - even after an infinite cycle - a new "permanent-stone" is not "enabled". If only one cycle were used and stopped, then there would be new permanent-stones. - My infinite cycles with ko-passes simply combine the J1989 infinite cycles without ko-passes and the availability of ko-passes. Maybe the rules authors did not think of this possibility at all, but it is the consequence of their machwerk.

Of course, J1989 style rules can be formulated using a Cycle End Rule (on occurrence of a cycle, a hypothetical sequence ends). This can lead to different behaviours in arcane examples and different statuses without scoring impact (such as alive ko stones in double-ko sekis).

Japanese style rules do NOT NEED ANY KO-PASS RULE. Without, the following two examples have a different behaviour:

1) direct teire ko + elsewhere double disturbing death

2) triple ko with one external ko

If the J1989 authors could have accepted (2) (they were not aware of the more "frequent" (1), it seems, which Winfried Borchardt pointed out), they could have used the same basic ko rule used during the regular game alternation. (The Koreans fell into the same trap of wishing to have a particular outcome for (2). This causes problems in the Korean 1992 Rules and the Asian Games 2013 Rules.)

Yes, that's true.

It seems to me that it is possible to reach the "favoured" results of most the official commentary's examples without a rule of this type, and even the rules-intrinsic results (not the "favoured" ones) for the examples 16 to 18 (if we forget about the sudden, but unexplained, "collapse of a Seki").

Even an explicite definition of a "locality" is not mandatory, despite the need for some "implicite" usage, but only for the points that are set free by the capture of a string (and of which at least one has to become occupied permanently to achieve some special status of this string).

I assume that it might be a matter of taste (but not of effort, or complexity), how to first identify different status of strings, for the later combination for the assignment of "alive" (may be and "in Seki") and "dead".

In one way or the other, one has to identify

(1) Strings that are the "owner" of at least two forbidden points,
(2) Strings that are not of type (1), but cannot be taken off the board by actual play [[usually related to "Seki"]], and
(3) Strings that are neither of type (1), nor of type (2) [["pending" strings]].



Do you refer to some of the official commentary's examples ?

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The really most difficult Go problem ever: https://igohatsuyoron120.de/index.htm
Igo Hatsuyōron #120 (really solved by KataGo)

It is not necessary to define seki in Japanese style rules. See, e.g., the Intermediate Step Rules in
http://home.snafu.de/jasiek/j1989c.html
or create a hybrid of the Simplified Japanese / Korean Rules. (Actually, I have created such, but not published it. It is straightforward: just throw in a few "independently alive" phrases in the dead stone removals + territory definitions.)

I do not refer to official examples. For (1), there is none. For (2), you can, of course, look at II.8.

This is surely one of the "other" ways )


It is impossible (with Japanese style rules) to reduce something like "alive with territory" / "alive without territory" / "not alive" to only two status !

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The really most difficult Go problem ever: https://igohatsuyoron120.de/index.htm
Igo Hatsuyōron #120 (really solved by KataGo)

It seems we were not meaning the same with "undesired ko-pass cycles".
In my understanding the problem in your example only comes up because w can endless delay the capture of the single w stone on the right by alternately making a ko-capture and a ko-pass.
Instead of lifting all ko-bans with a ko-pass I'm more with Bill's solution and let the ko-pass only lift a special ko-ban and stop the cycle otherwise.


Less confusing, but also less mysterious


It's nessecary to prevent or stop the cycle. You have some freedom how to interpretate the result, but treating it the same as ending with two passes wouldn't work correctly.
For making a decision you should consider the comment to the long life (example 6).
For me it's difficult to interpretate all the comments absolutely consistent and it seems to me that they wanted ensure the correct result only but gave simply a reason that comes first to mind to justify it. But in general you cannot transfere the reasoning on other cases.

"they wanted ensure the correct result only"

In this case, it would have been much better if they had provided a selection of "special positions", together with the "officially" given status. Nothing more.
By the way: "intended" would be a better term for "correct".

Seen overall, the examples are NOT consistent (the Japanese tried to develop a consistent way of derivation, but in vain).

Especially (in my opinion) the examples with the sudden "collapse of the Seki" are inconsistent, because these can only be explained using a mismatch of "status confirmation", and "scoring".

Confirming strings to be "dead" is part of "status confirmation", but taking these stones off the board without further play, is part of "scoring". However, there is nothing said in the Rules that "scoring" might be interrupted, to do some "status confirmation" again.

Therefore, it is not very surprisingly that the consistent application of other rule-sets gives different results for some examples than the offical Japanese Rules' text.

_________________
The really most difficult Go problem ever: https://igohatsuyoron120.de/index.htm
Igo Hatsuyōron #120 (really solved by KataGo)

For me the "collapse of the Seki" is not the worst. If you add a rule that ensures you cannot endless delay the capture (by a cycle with ko-capture and ko-pass) you can prove that the "seki" is capturable in it's own analyse.
For me the most complicated thing was to assimilate all the comments about cycles and there interpretation, especially because some comments indirectly add comments or implications to that topic.


Of corse other rules give other results, else they would be the same (equivalent) rules

However for generating a model for j1989 it is required at least:
- the rules are effective decideable in all situations
- the rules give the same result in all examples from the commentary

The positions that include a merger of "Double-Ko" and "anything else" are treated (according to the intended result) as if their merged components were independent from each other (, but which they are not). Just saying: "First, decide on the 'anything else' alone. Re-arrange the position according to this result. Then, decide on the 'Double-Ko'."

By the way: In my opinion, it does not make any sense to restrict "cycles" during "status confirmation".


"Cycles" caused no problems for me. So, our viewpoint may be different.

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The really most difficult Go problem ever: https://igohatsuyoron120.de/index.htm
Igo Hatsuyōron #120 (really solved by KataGo)

It depends on how you treat them. I agree that the reasoning of the comment is a bit strange or confusing.
In my view the double-ko and the "anything else" ARE independent from eachother. (Actually all strings are independent from eachother, so there are more than two things.)
To show that the "anything else" is dead I can simply prove it by capturing it and the double-ko doesn't matter IF THERE IS A RULE THAT COVERS THESE CYCLES.
To show that the double-ko is dead requires first to capture the "anything else" (which itself has no meaning for the double-ko in this analyse) and after that you can capture the double-ko. As said above there may be more than only two playouts if there are more than two strings.


Maybe the viewpoint is different or maybe only the starting point. To make rules that works correctly in some situations is quite easy, but when you add more rules to cover more situations it becomes more and more difficult not to change the things that have worked before. There were some situation where I had the choice to make one thing easy at the cost of making another thing complicated or vice versa.

Have you thought about the comments (and implications) to the long-life in the official commentary?
I slightly recall that I found a deeper problem with this but I never was able to create a position that shows it - maybe I just saw a ghost - and atm I cannot remember my thinking about.

To be honest, I have not thought about it really hard.

However, in my opinion, the comment (referring to "repetition" >>> "no result") is somewhat incomplete.

Within the given context, "repetition" must refer to the complete "state" of the game. This "state" does not only include the visible board-position, but also the captured stones. To declare a "repetition", the difference of captured stones must be the same with both visible board-positions.

I suppose that such a "repetition" cannot happen within less than four moves. But I have no idea whether it might be preferable (for "guarantee" reasons) to have something like "... before at least four moves ..." explicitely written.

_________________
The really most difficult Go problem ever: https://igohatsuyoron120.de/index.htm
Igo Hatsuyōron #120 (really solved by KataGo)