In what context are you Cassandra? In all rules I know, if the exchangeCassandra wrote:I think it was Robert's intention to develop a logically closed and contradiction-free set of rules, which was able to achieve the desired results of the J89 life-and-death examples.Gérard TAILLE wrote:BTW, though the global ko-pass defined in J2003 is also a big progress, it is a pity to see that the status of white stones is still dead stones (=> seki => white should add a move)
As far as I understand J2003, this particular ko-pass-rule is both appropriate and necessary to fulfill the above-mentioned task.
By the way: It does not matter that White would have to add a move to get rid of the seki in J89 status corfirmation.
During actual play, Black is able to capturewith
, forcing White to connect at
, also gaining that specific point, due to the just won prisoner.
Japonese counting
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Re: Japonese counting
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Re: Japonese counting
J89, but apparently I was mistaken
+ + + + + + + + + + + + + +
If Black does nothing, White has to add a move during "play", in order to avoid "seki" by status confirmation.
White has ten points occupied with dead Black stones => 20 points.
White has six points of unoccupied territory => 6 points.
Black has two points of territory => 2 points.
=> White wins the game by 24 points.
During "play", Black plays his kikashi in the upper left.
White has eleven points occupied with dead Black stones => 22 points.
White has six points of unoccupied territory => 6 points.
Black has two points of territory => 2 points.
Black got one prisoner => 1 point.
=> White wins the game by 25 points.
It seems that I did not visualise before that capturing one White stone empties the respective point, turning it into White territory.
+ + + + + + + + + + + + + +
If Black does nothing, White has to add a move during "play", in order to avoid "seki" by status confirmation.
White has ten points occupied with dead Black stones => 20 points.
White has six points of unoccupied territory => 6 points.
Black has two points of territory => 2 points.
=> White wins the game by 24 points.
During "play", Black plays his kikashi in the upper left.
White has eleven points occupied with dead Black stones => 22 points.
White has six points of unoccupied territory => 6 points.
Black has two points of territory => 2 points.
Black got one prisoner => 1 point.
=> White wins the game by 25 points.
It seems that I did not visualise before that capturing one White stone empties the respective point, turning it into White territory.
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Re: Japonese counting
OK Cassandra, I think we agree now that black, in normal play, cannot have any interest to take the ko in the corner instead of passing to stop the game.Cassandra wrote:J89, but apparently I was mistaken![]()
+ + + + + + + + + + + + + +
If Black does nothing, White has to add a move during "play", in order to avoid "seki" by status confirmation.
White has ten points occupied with dead Black stones => 20 points.
White has six points of unoccupied territory => 6 points.
Black has two points of territory => 2 points.
=> White wins the game by 24 points.
During "play", Black plays his kikashi in the upper left.
White has eleven points occupied with dead Black stones => 22 points.
White has six points of unoccupied territory => 6 points.
Black has two points of territory => 2 points.
Black got one prisoner => 1 point.
=> White wins the game by 25 points.
It seems that I did not visualise before that capturing one White stone empties the respective point, turning it into White territory.
It remains only the question : in normal play, should white add a move before passing?
In J89 and J2003 we proved white should add this move due to the you use of the pass-ko rule.
In viewtopic.php?p=266571#p266571 you claimed that with your own understanding of japonese rule (I mean not the current J89 or J2003 as they are written) white should not add a move and I agree with you because in normal play black cannot save her stones even by playing first! For that reason I think the pass-ko rule, without minimizing the number of advantages it has, has though here a flaw which was certainly not expected.
Do you agree Cassandra?
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Re: Japonese counting
OK Cassandra let's try to have a common understanding of tripel ko or double.Cassandra wrote: Do you want to behave a final position differently, whether it contains a solidly connected TRIPLE-Ko that is shared by only two groups
Let's begin by the solidly connected TRIPLE-Ko which seems the easiest one.
In J89 and J2003 (where I am talking about J89 or J203 I am refering strictly to the test and not to the examples because they could be not coherent with the text), my understanding is the following:
In J89 the marked stones are dead because they can be captured and no new stone are enable to be played that the opponent could not capture. All other stones are alive => the left part of the board is seki
In J2008 the three single stones are also dead due to the double barrier with black and white marked stones. All other stones are alive => the left part of the board is seki
Is seki the expected result? I do not know but the losing player made a mistake by passing. She would have continue the game by playing the triple ko to reach a NO RESULT game. IOW the result of the confirmation phase is not relevant. In any case the potential losing player can always continue the game to reach a NO RESULT.
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Re: Japonese counting
In principle, yes.Gérard TAILLE wrote:For that reason I think the pass-ko rule, without minimizing the number of advantages it has, has though here a flaw which was certainly not expected.
Do you agree Cassandra?
However, in my opinion the only "advantage" of such a special-ko-ban rule is to ensure the intended results of several of the life-and-death examples of J89. Otherwise, it would not be needed, in order to create a self-contained, contradiction free rule set.
I consider it extremely likely that for EVERY ruleset "beast" could be created, which status-confirmation result "common sense" did not expect.
But let's return to J89.
I suppose that the inventors of the special-ko-ban rule wanted to avoid "no result" in several TRIPLE-KO cases.
But it seems that they overlooked the effects of their rule on "NESTED" ko shapes (as in the board position you created). The status-assessment of the position reached after two moves (Black captured in the upper left corner, White connected the resulting atari below) -- if THIS position was the final position of the game -- would match "common sense".
As you corrected me, Black's initional move would COST him one point -- if played BEFORE the game stopped.
So, what it the reasoning that he shall GAIN one point without capturing during play -- through status-confirmation?
+ + + + + + + + + + + + + + + +
By the way:
The life-and-death examples in J89 -- treating a compound of bent-four and double-ko -- do NOT cover ALL possible variations of shared double-ko formations. J89 suppresses an example like the following one -- with NESTED ko shapes.
To be honest, I have forgotten ("misplaced") the results of my J89-application trials with it. But for sure, at that time I did not dream of some restricting side conditions that prevent any triple-ko cycles.
However, I know that a status-assessment without any special ko-ban-rule will give interesting results (as well).
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Re: Japonese counting
I think you hit the nail on the head.Gérard TAILLE wrote:Is seki the expected result? I do not know but the losing player made a mistake by passing. She would have continue the game by playing the triple ko to reach a NO RESULT game. IOW the result of the confirmation phase is not relevant. In any case the potential losing player can always continue the game to reach a NO RESULT.
This is just what I meant.
If the three ko shapes are solidly connected, and consequently only two groups involved, the (J89) result of the status-assessment of this triple-ko shape would be SEKI.
=> Probably one player would prefer "no result".
If the three ko shapes are seperated (e.g. into a double-ko and a simple ko), the J89 examples enforce the death of several groups, ruling out the possibility of SEKI.
Does this mean that a triple-ko is not a triple-ko?
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Re: Japonese counting
Oops there are big differences betweeen a solid triple ko and the following position.Cassandra wrote:I think you hit the nail on the head.Gérard TAILLE wrote:Is seki the expected result? I do not know but the losing player made a mistake by passing. She would have continue the game by playing the triple ko to reach a NO RESULT game. IOW the result of the confirmation phase is not relevant. In any case the potential losing player can always continue the game to reach a NO RESULT.
This is just what I meant.
If the three ko shapes are solidly connected, and consequently only two groups involved, the (J89) result of the status-assessment of this triple-ko shape would be SEKI.
=> Probably one player would prefer "no result".
If the three ko shapes are seperated (e.g. into a double-ko and a simple ko), the J89 examples enforce the death of several groups, ruling out the possibility of SEKI.
Does this mean that a triple-ko is not a triple-ko?
Assuming neither player can allow losing her big group at the top the result is not necessarily a NO RESULT as with a solid triple ko.
As you can see black as a serious advantage because black can force a NO RESULT game.
For white it is quite different because she cannot force a cycle in normal play. After: the game stops and white must resume the game to continue the game. If we assume white is not allowed to resume the game an infinite time then the game will definitly stop and the confirmation phase will take place.
In J89 you already showed that a loop can take place in this confirmation phase => white is alive => seki.
If this result is enough for black to win then it will be the result of the game. But if the seki implies a losing game for black then black will choose to play the triple ko to reach a NO RESULT.
Comparing to the solidly connected triple ko it is quite different : the player with the advantage (here black) cannot lose, the result will be either a win of this player or NO RESULT depending of the score in case of seki.
In J2003 it is quite different: this
In J2003 all the white stones are dead.
Here again we can ask yourself what is the expected result but I do not know what japonese professionals will decide.
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Re: Japonese counting
I am happy that we agree that the types of triple-ko I mentioned are different.Gérard TAILLE wrote:Comparing to the solidly connected triple ko it is quite different : the player with the advantage (here black) cannot lose, the result will be either a win of this player or NO RESULT depending of the score in case of seki.
Positions, which have a one-sided advantage, are usual also in J89. Therefore, it does not matter whether both sides can enforce a NO RESULT, or only one.
If Black cannot lose, as you finally concluded, the only reason left for beating the White stones to death during status-confirmation is to avoid NO RESULT (i.e. no win for Black) in the case that White would win even with this position kept as a seki.
This is exactly what I mentioned as likely motivation of the authors of J89.
But why on earth should it be mandatory for the party, which large triple-ko portion is sandwiched between opponent's groups, to win a game of Go?
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Re: Japonese counting
OC I agree with you. In addition let's look at the example 11: In J89 the white marked are still alive because of the loop in the confirmation phase in top right corner.Cassandra wrote:I am happy that we agree that the types of triple-ko I mentioned are different.
In J2003 these stones are dead.
Surely it is a failure of J89 isn't it?
More generally J89 fails to handle double ko as I showed you with the example: By the way, in J2003, you have two different ways for killing white stone marked: or you can use the following barrier and play which seems more in the spirit of J2003!
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Re: Japonese counting
Look againGérard TAILLE wrote: In J89 the white marked are still alive because of the loop in the confirmation phase in top right corner.
J89 translation wrote:If both these positions are present on the board, the seven white stones on the left are dead while the enclosed black and white groups on the right are both alive in double-ko seki.
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Re: Japonese counting
I told you already that example 11 is nonsens in the pedagogical sense.Gérard TAILLE wrote:More generally J89 fails to handle double ko as I showed you with the example:
Final position of the game.
Let us do the status confirmation for the marked White stone.
This is the correct mirror for what is commented in example 11.
White's marked stone can be captured, but no new White stone can be played.
This sequence would be shorter.
White might even do nothing.
The marked White stone is "dead".
Would be he same here.
And also here.
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Re: Japonese counting
Dear Gérard,
you were not right with your conclusions above, regarding J89, but you might have found the clue for solving examples 16 to 18 as intended.
Let's try to apply the example 11 commentary on problem 16...
Do you remember this formation at the top?
Looks a bit like example 11, doesn't it?
But example 11's "White's stones at the left are dead, and the two groups at the right are alive in double-ko seki" would not lead to the intended result of this example.
So let's continue ... Ups, "collapse of the seki"!
+ + + + + + + + + + + + + + +
Would be the same here, where example 11 arises earlier as above.
Again a clone of example 11
+ + + + + + + + + + + + + +
This procedure would imply that "pass-for-ko" was intended to be done in order of the ko captures.
But this cannot be really true, can it?
you were not right with your conclusions above, regarding J89, but you might have found the clue for solving examples 16 to 18 as intended.
Let's try to apply the example 11 commentary on problem 16...
Do you remember this formation at the top?
Looks a bit like example 11, doesn't it?
But example 11's "White's stones at the left are dead, and the two groups at the right are alive in double-ko seki" would not lead to the intended result of this example.
So let's continue ... Ups, "collapse of the seki"!
+ + + + + + + + + + + + + + +
Would be the same here, where example 11 arises earlier as above.
Again a clone of example 11
+ + + + + + + + + + + + + +
This procedure would imply that "pass-for-ko" was intended to be done in order of the ko captures.
But this cannot be really true, can it?
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Re: Japonese counting
Dear Cassandra,
My diagram above propose only one position which is the position in which the game stopped.
For this position we need to apply the confirmation phase to get the status of all groups.
Assume I begin by analysing white groups, ignoring for the moment the status of black groups of stones.
Seeing in the rule the statement "Stones are said to be "alive" if they cannot be captured by the opponent, or ...", I begin by looking for uncapturable white groups and here is the result:
the marked white stones are uncapturable => they are alive.
Now I have to look for the status of the other white groups and I decide to consider the white stone in the bottom right corner.
Variation 1: and I see white has been able to put on the board new uncapturable stones in the upper left corner (remember that, at this time of the analysis I do not know which black groups may be uncapturable if not two-eyed groups).
For black, let's try another variation to try and prove the white stone in the bottom right corner is dead.
Variation 2:
pass-for-ko created by
pass-for-ko created by
pass-for-ko created by
pass-for-ko created by 
This loop can continue forever while the marked white stone in the bottom right corner is still not captured.
According to the article 7.1 the white stone in the bottom right corner is capturable but is alive.
In J89 no indenpendancies are defined between groups of stones (in J2003 we have the local-2 concept but not in J89). Indirectly the pass-for-ko rule creates a kind of independancy but it does not work very well here.
What in J89 rule can avoid the white defense above? (this defense does not work in J2003).
Example 11 is not clear because on the same diagram two positions are presented and we may think they are independant positions. In that sense your are right OC => let's forget this example 11.Cassandra wrote: Final position of the game.
Let us do the status confirmation for the marked White stone.
This is the correct mirror for what is commented in example 11.passes for the positon under investigation, not for lifting the ko ban in the double-ko!
My diagram above propose only one position which is the position in which the game stopped.
For this position we need to apply the confirmation phase to get the status of all groups.
Assume I begin by analysing white groups, ignoring for the moment the status of black groups of stones.
Seeing in the rule the statement "Stones are said to be "alive" if they cannot be captured by the opponent, or ...", I begin by looking for uncapturable white groups and here is the result:
the marked white stones are uncapturable => they are alive.
Now I have to look for the status of the other white groups and I decide to consider the white stone in the bottom right corner.
Variation 1: and I see white has been able to put on the board new uncapturable stones in the upper left corner (remember that, at this time of the analysis I do not know which black groups may be uncapturable if not two-eyed groups).
For black, let's try another variation to try and prove the white stone in the bottom right corner is dead.
Variation 2:
This loop can continue forever while the marked white stone in the bottom right corner is still not captured.
According to the article 7.1 the white stone in the bottom right corner is capturable but is alive.
In J89 no indenpendancies are defined between groups of stones (in J2003 we have the local-2 concept but not in J89). Indirectly the pass-for-ko rule creates a kind of independancy but it does not work very well here.
What in J89 rule can avoid the white defense above? (this defense does not work in J2003).
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Re: Japonese counting
I'm afraid nothing EXPLICITELY mentioned in the text can prevent this.Gérard TAILLE wrote:What in J89 rule can avoid the white defense above? (this defense does not work in J2003).
I think that this is a side-effect of the flawed special ko-ban rule that the authers of J89 were not aware of. I am sure that this special rule was designed for several application cases of triple-ko. Probably double-ko flew under the radar...
What makes things even worse: The explanations of the life-and-death examples support your assessment.
+ + + + + + + + + + + +
Example 1:
Status assessment for White's marked stone.
It can be captured.
White can recapture, so the status is still pending.
White's stone is captured for a SECOND time.
Does this mean that the J89 story ends here? Reborn but killed again?
NO!!!
White connects.
Black connects.
J89 declares the status of White's captured stone as "alive", because two uncapturable new stones could be played.
But are these stones played
-- AFTER White's stone had been captured for the first time, or
-- AFTER White's stone had been captured for the second time?
In the case of the latter, the new uncapturable stones would be irrelevant.
White's stone would be "dead".
Additionally, and this returns to your problem ...
... the new uncapturable stones are played at board points, where Black did NOT capture any White stone, and which were occupied by Black before.
I.e. there was NO rebirth of White's captured stone in the narrow sense.
If we were fond of "locality", we could swallow a sedative pill:
Everything happened inside the surrounding fencing by "two-eyed alive" groups.
But worse is to come ...
+ + + + + + + + + + + + + +
Example 4:
Status assessment for White's stones.
Black tries to capture.
The sequence shown in J89 ends with this final position.
But is is clear from the comment that the sequence during "play" is shown, which resolves the temporary seki.
You will realise that NO uncapturable White stone has been played yet, AFTER White's group at the top has been captured.
Therefore, White needs another move at the left to enable J89 declaring the captured White stones "alive".
Again, as in example 1, NO White new uncapturable stone has been played at board point, which was occupied by White's captured stones before.
I.e. NO rebirth in the narrow sense.
Contrary to example 1, there is NO "locality" sedative pill available here!
White's "new uncapturable" stone is played OUTSIDE the surrounding fencing by "two-eyed alive" groups.
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Re: Japonese counting
This nested type of a double-ko might be also missing as example 16A ...Cassandra wrote:By the way:
The life-and-death examples in J89 -- treating a compound of bent-four and double-ko -- do NOT cover ALL possible variations of shared double-ko formations. J89 suppresses an example like the following one -- with NESTED ko shapes.
To be honest, I have forgotten ("misplaced") the results of my J89-application trials with it. But for sure, at that time I did not dream of some restricting side conditions that prevent any triple-ko cycles.
However, I know that a status-assessment without any special ko-ban-rule will give interesting results (as well).
And this one as example 16B ...
And this one as example 18B ...
There might be a reason that J89 does NOT have the SANDWICHED (i.e. inner) group of the double-ko with NESTED ko shapes.
Last edited by Cassandra on Thu Aug 19, 2021 10:04 am, edited 1 time in total.
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