I have stated my opinion elsewhere that the pass-ko ban remains there as long as the hot stones is on the board.

I think you can also consider this shape when white is clearly dead because of pass-ko.

Click Here To Show Diagram Code

[go]$$W
$$ -----------------------
$$ | . X X O O . O X . O .
$$ | . X O O . O X X . O .
$$ | O O O O O X X X O O .
$$ | X X X X X X O O O . .
$$ | O O O O O O O . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .[/go]

Rather than ask if the ko is the same, should we ask if it is really the intention in j89 to let one side win a ko that would require a ko threat? Both of these position we have situation that white would win the ko if neither side had a ko threat, it appears odd to me that we would decide against white if there is not supposed to be ko fights in status confirmation.

I had the same understanding Kvasir but now I have a doubt:

Click Here To Show Diagram Code

[go]$$W
$$ -----------------------
$$ | . X X O O X a X . O .
$$ | O X O O X . X X O O .
$$ | O O O O O X X X O . .
$$ | X X X X X X O O O . .
$$ | O O O O O O O . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .[/go]

"a" was a ko earlier and "a" may be a ko in the future but in the position above "a" is no more a ko. How a pass-for-unexistent-ko can make sense?

I think we may just be at the end of the line for pass-ko.

1. It doesn't seem to give the results we want.
2. It raises questions that wouldn't otherwise need to be answered precisely.
3. It is fairly tricky to actually use this rule.

This is what I referred to here and here. This seems significant well beyond J89, because a complete ruleset will likely need (for moonshine kos) to EITHER rely on "wholeboard position" (like superko) or include rules referring to "the same ko". OC, both have huge weaknesses.

It does not make sense to want to heal errors during "play" in the subsequent L&D analysis.

Click Here To Show Diagram Code

[go]$$W
$$ -----------------------
$$ | . X X O O 1 O X . O .
$$ | . X O O . O X X . O .
$$ | O O O O O X X . O . .
$$ | X X X X X X . O O . .
$$ | O O O O O O O . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .[/go]

White would connect with , wouldn't she?

_________________
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Igo Hatsuyōron #120 (really solved by KataGo)

After some contemplation I think this example is suspect because of blacks outside liberty.

Click Here To Show Diagram Code

[go]$$W
$$ -----------------------
$$ | . X X O O . O X C O .
$$ | . X O O . O X X O O .
$$ | O O O O O X X X O . .
$$ | X X X X X X O O O . .
$$ | O O O O O O O . . . .
$$ | . . . . . . . . . . .
$$ | . . . . . . . . . . .[/go]

The rules include the following commentary.



We have actually discussed this before, how the commentary says that dame is required to be filled and then shows examples that apparently state it is too late to fill dame. At any rate, examples that dispute the life and death but leave an outside dame are suspect.

You could create an example were the outside white group may be dead but you may find that it is then black that is failing to fight the ko.

I do not see your point Kvasir.
In NORMAL PLAY and black to play then Black stones are dead because white has the advantage in the following ko fight. Now I just ask if they are also dead in CONFIRMATION PHASE which is less obvious.

What is dame and what is a point of territory next to a dead string depends on status. During a dispute you cannot tell this in advance.

Yes Jann I noted your interesting comment in https://www.lifein19x19.com/viewtopic.p ... 46#p267746

Click Here To Show Diagram Code

[go]$$B
$$ ---------------------
$$ | . . X X X X O X . .
$$ | X X O X O X O X . .
$$ | X O 1 O . O O X . .
$$ | O 2 O . O O X X . .
$$ | O . O O O X X . . .
$$ | O O O X X X . . . .
$$ | X X X X . . . . . .[/go]

After the exchange it is true that the strings adjacent to the ko have changed but according to article 6 the ko itself has not disappeared. For that reason I searched for a another (more?) convincing situation.
I do not know if the original text in japanese can help but seeing the english text it is not clear what happen for pass-for-ko request when a ko disappears and reappears later : is it a new ko at the same place or is it the same ko?

I don't think this was ever defined anywhere, so you are on your own.

"A ko capture is IN THE SAME KO as another ko capture if it is in the same ko mouth formed by the same strings."
(change strings to stones for the other, less strict way - the third, most liberal way won't even require same stones)

I'm still reluctant to actually suggest such definition (or any other definition for this), but some reasoning can be found, even theoretically. What happens if you judge NOT same ko? You get normal ko behavior, which is almost never wrong. So the strictest definition may be the most safe. OC with J89 you also need to worry about Japanese compatibility... This whole thing is a mess, and the mere fact that this is a question is a weakness of these ko-related special rules.

My point is that the liberty is on the outside of the group and connected to a group of the other color that is alive, but please bear with me I am going to try to elaborate.



Assuming the black group is not removed from the board at the end of the game I called the liberty dame because that is exactly what article 8 says. If the black group is to be removed then this liberty is territory.

So what is suspect about the problem? Maybe it is our understanding or the interaction of our understanding with the actual method of pass-ko, but I feel there is something suspect here. Which may not be saying much new.

We have discussed before (maybe I can link it if I find it) that while article 8 seems to say that "dame makes seki" this has been rejected in practice. So if we are to conclude that the liberty is dame but the outside stones are not in seki, is this not a contradiction?

To boil it down, I do find the problem to be suspect because of the position of the liberty. One may sometimes conclude that this is seki if the outside group could be captured once the ko starts. On the other hand if one assumes the outside group is always alive then we have this contradiction of a dame that is connected to dead stones of one color and alive of the other.

I don't think j89 has strong enough statements about dame and seki to allow one a proof by contradiction that overrides what has already been shown using the pass-ko method (which raises the question of 'what is ko?') but I am now doubting one should accept it.