I didn't mean any specific prohibition rule, just pointed to the fact - like earlier, with "no infinite resumptions" - that turning double kos into perpetual repetition via the forcing nature of ko passes there is obviously not acceptable in J89 (even if its poor wording/formalization would allow that, which the authors overlooked).

Did you ever notice that endless repetition is badly needed in life-and-death example 6?

Have you already understood what would happen, if the terminating move of a double-ko cycle during status confirmation was prohibited?
Do you want to have an enforced tenuki inserted after the second ko capture into a double-ko, and after the second pass-for-ko as well?

Did you ever want to win a game of Go by claiming
"I won this game. As you know for sure, dear opponent, I intended to win, so the win in mine!"?

I am sorry to say that, but the entire work of J89 lacks professional attitude.
And that cannot be disputed away with "But the authors intended ...".

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

I don't know what "badly needed" means. LD ex 6 shows uncapturable W stones and capturable B stones (which forces B to start the loop in the game).


For the double ko problem you don't want to prohibit the first or last or any specific move in the "cycle", but the infinite repetition power of ko passes. But again, I don't propose any specific fix/hack for an already (IMO) poor rule design. This doesn't mean that a poorly worded ruletext would take precedence over the intended meaning or the actual game as it's played. If so, there wouldn't be triple ko voids in Chinese professional go.

It would be nice to have flawlessly formalized Japanese (and Chinese) rules, but currently there isn't.

Endless repetition is mandatory.


As you can easily see, should you open your eyes, endless repetion is mandatory for confirming White's four stones in the corner "alive".



You haven't already understood, have you?

If you want to prohibit an endless repetition of

capturing into the ko A of the double ko
capturing into the ko B of the double ko (enforced)
ko-pass for the ko B of the double ko
ko-pass for the ko A of the double ko (enforced)
see
see
see
see
see
...

you will have to declare at least one of the moves in the cycle for "taboo".

There are several options for doing so:

==> is taboo
Effect: Capturing into a double-ko is forbidden.

==> is taboo
Effect: White will capture Black's double-ko group. Termination of the endless repetition of the cycle.

==> is taboo
Effect #1: White must tenuki, but might not have any spot on the board available where she could place her stone. If so, it did not make any sense to have played , she could have passed instead. Again, there will be no capturing into a double-ko, despite it would not be explicitely prohibited here.
Effect #2: Black might start another double-ko cycle by playing a ko-pass with . It will follow . A repetition of would be taboo, as it were the first pass-for-ko in that cycle. Black must tenuki, but -- contrary to White -- he will always find a beneficial spot on the board where he can place his stone. White might even surrender in the very beginning, as Black might be able to play TWO moves in a row elsewhere.

==> is taboo
Effect: White will capture Black's double-ko group with her move (not the one defined above) . Termination of the endless repetition of the cycle.

==> is taboo
Effect #1: White must tenuki, but might not have any spot on the board available where she could place her stone. If so, it did not make any sense to play , she could have passed instead. Again, there will be no capturing into a double-ko at all, despite a first capturing would not be explicitely prohibited here.
Effect #2: Black is unable to start another double-ko cycle with reversed colours, as would be the cycles very first move. Same effect as with declaring taboo: Capturing into a double-ko would be forbidden.


As you can easily realise, only and will terminate the double-ko cycle.
is the move that completes the cycle, and prohibiting such move is what I suggested.
Prohibiting would be an alternative option. If you chose this one, you would discover at once that prohibiting a double-ko cycle does not make any sense at all.

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

The stones are uncapturable, whether B tries the cycle or something else. I don't see your point here.


For the third time, I don't want to try patching up an already poor rule invention, but turning this into something like superko (worrying about which specific move is to be prohibited) is a bad track for sure. The problem is that J89 ko passes do not match the theory behind inventing them, so if anything this is to be addressed.

Let me say that this example 6 has absolutly no interest providing both player have the same understanding of the rule.
If both players know that white will win if the game ends here then black will not pass => the cycle will never stop during normal play => NO RESULT game.

As Jann, surely I am not motivated to discuss in detail on this J89 rule. I prefer by far to discuss J2003, or Cassandra proposal, or my own proposal.

The latter is true, Gérard.

But be warned:
There are several examples of status confirmation that will never see the end of the game if both players know the status confirmation's result.
This result may or may not vary according to the rules applied.
If there is a difference, it may or may not affect the real game.


To refuse a discussion of a fraction of such positions is therefore a contradiction in terms.

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

Discussion positions is fine but discussing them with J89 is less motivating

In my bookcase there is, among other things, Go Seigen's 10-volume "Go of the 21st Century".

I think, discussing "Go Rules of the 21st Century" will be fine.

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

Thanks for the explanation, I have only now taken the time to understand it in the context of J2003, or at least try to. Far from a definite understanding of J2003, however, I think I have got the point that matters. And I'm also curious now about Robert's comment on your example.

I do not always answer a comment because it could be only a simple comment. If it is a clear question on an exemple OC I try my best to answer the question.
What is this example your are referring to, and what kind of clarification you are waiting for?

I was referring to your position and your question to Robert in
https://www.lifein19x19.com/viewtopic.p ... 73#p266573
I agree with you that
- the small black group on the right is alive while the left one is dead (according to my certainly still incomplete knowledge of J2003)
- this status of the left black stones (dead stones) is not what we would expect.

No, I expected the left black stones being in-seki alive because if white tries to capture them then black will get a lot of new permanent-stone on the right. But this position is quite "special" because all these new permanent-stones on the right are outside the local-2 area associated to the left black group. This point is quite unusual when all the position is recognize as a seki.

BTW jmeinh, with this position you can see that J2003 may be considered not quite efficient: the rule tells you to determine the status of all groups in order to conclude if we are or not in a seki. Here the status of the black groups at the left and at the right does not matter. They could be dead or alive but any case all the position is seki.

Yes, I would also expect the left black stones being in-seki. And all the other stones too.
But application of J2003 leads to the result that the left black stones are dead and the left white chain is alive with territory, isn't it?

NO, "territory inside" requires "no dame outside" under J2003.

This is why it does not matter whether the partial groups of a composite seki are "dead" or "alive" by their status assessment.

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

ah, that is, J2003 leads to strange looking intermediate results for this position, but the score is in line with our expectations.

Yes that is the point.
In my post https://www.lifein19x19.com/viewtopic.p ... 70#p266570 this is exactly what I said by
"(only for the status of the strings of stones, not for the result of the game!)."

TERRITORY rules ALWAYS require a TWO-step process to identify territories. This can NEVER be done in only one step, because there is also "live in seki"!

The common practice (e.g. J89, J2003) includes the status assessment for the individual groups as a first step.
As a second step, its results are combined in the sense of "territory can only exist within groups that live independently".

Gérard's proposal might look like a one-pass procedure at first sight, but a deeper look will reveal that it also uses TWO steps.
The first, though not very eye-catching, step is the identification of the "borders". With this miracle tool, Gérard avoids the seki issue, at least explicitely.
In the second step, with the creation of two-eye-formations, a distinction is also made between seki and independently living groups, albeit implicitly. "If you didn't succeed, your chosen formation contained at least one seki." Thus we will probably see an iterative process here from time to time, dependent on the difficulty of the formations, until the proper border has been found.

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

Yes Thomas identification of the territories together with its borders is essential in "GT territory rule" but in practice any player had indirectly already identified these territories and borders at least during the end of the yose and during dame play. In practice any (experimented?) player knows perfectly where exactly she will claim for territory because during a very great part of the game , if not all the game, an experimented player look carefully to her potential territory and its (future) border.
For this reason, in practice, this step counts for almost nothing, even with complexe sekis, simply because these situations were already carefully analysed during the normal course of the game.
In my mind that point is even one of the major advantage of the "GT territory rule": the starting point of the confirmation phase, i.e. the identification of potential territories with its border, have already been done during the game and as such is very natural.

In J2003 I see more steps:
1) find uncapturable groups of stones (with hypothetical play)
2) find capturable-1 groups of stones (with hypothetical play)
3) find local-2 area (without hypothetical play)
4) find capturable-2 groups of stones (with hypothetical play)
5) finally all results are combined in the sense of "territory can only exist within groups that live independently"
In addition it appears in J2003 local-3 area and capturable-3 but I do not know what they are for.

I think you prefer your rules too much about "was analyzed during the game".

The big advantage of your approach is that it was probably the very first time that it was possible to cast into a framework of rules what actually happens in the mind of the player.

Or do you really assume that players acting in my unfinished "two-eyed alive" world would proceed as follows after the end of "play"?
Let's check for each and every string on the board, whether it fulfills "two-eyed alive" option #1.
Let's check for each and every other string on the board, whether it fulfills "two-eyed alive" option #2.
Let's check for each and every other string on the board, whether it fulfills "two-eyed alive" option #3.
Let's check for each and every other string on the board, whether it fulfills "in-seki alive" option #1.
Let's check for each and every other string on the board, whether it fulfills "in-seki alive" option #2.
Let's combine all the results of the status confirmation for each and every string on the board to identify territory.

For sure they would start taking the opponent's captives off the board. Same procedure as in your ruleset's world, or in any other as far it is a territorial one.

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