Japonese counting
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Gérard TAILLE
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Japonese counting
Black to play in japonese rules. How do you finish the game to get the best result?
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Mike Novack
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Re: Japonese counting
I suspect the lack of response is because not understanding what is meant by "best result" in a situation like this.
Maybe we just aren't seeing why all the outside black stones won;t die.
Maybe we just aren't seeing why all the outside black stones won;t die.
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RobertJasiek
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Re: Japonese counting
Speaking for myself, I have not responded because, by experience, writing down a careful rules application for this particular position requires ca. 3 to 4 hours.
(The term "counting" means the mechanical rearrangement or other physical procedure to count the score. The term "scoring" means the system or method by which the rules define what the score is for the game end situation determining the winner. The thread title means "Japanese scoring" while the counting procedure is immaterial for the OP's question. In ordinary, non-go English, the words counting and scoring are to some extent interchangeable. In go terminology since 1993, however, they have become terms with different meanings.)
(The term "counting" means the mechanical rearrangement or other physical procedure to count the score. The term "scoring" means the system or method by which the rules define what the score is for the game end situation determining the winner. The thread title means "Japanese scoring" while the counting procedure is immaterial for the OP's question. In ordinary, non-go English, the words counting and scoring are to some extent interchangeable. In go terminology since 1993, however, they have become terms with different meanings.)
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Gérard TAILLE
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Re: Japonese counting
You are right Mike. I think I failed to explain what was the problem in realtion with the rules.Mike Novack wrote:I suspect the lack of response is because not understanding what is meant by "best result" in a situation like this.
Maybe we just aren't seeing why all the outside black stones won;t die.
Surely Robert is right concerning the wordings "counting" or "scoring". I am not quite fluent in english but I do my best.
Let me propose a far simplier (and more efficient?) position:
Black to play. Obviously cannot save her stones on the top. My feeling is that black must play
pass
passand white wins by 11 points.
But I suspect it is only the feeling of an old player using J49 rule.
What about J89 rule? I am not sure but now the best sequence seems:
pass pass passand white wins by 10 points.
I am not sure of my rule interpretation. Thank you for an expert able to clarify the situation in J49 and in J89 contexts?
What is the point? After
pass 
pass the status of the black stones at the top is given by the confirmation phase and in this phase black can play at "a" in the top left corner and I do not see how white can kill the black stones. This defence does not exist in normal play because in the loop created black gives one more prisoner at each cycle. In confirmation phase however, the prisoners are not counted are they?-
RobertJasiek
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Gérard TAILLE
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Re: Japonese counting
OK Robert, let's begin by considering only J89. You propose black 1 at A7. What score do you expect to reach with this move? A white win by 10 points or 11 points or ?RobertJasiek wrote:Black 1 at A7 is another start to be considered.
J49? Serious?
It looks to me that this move loses one point but I may be wrong OC. Can you clarify how you finish the game after this move? IOW when will begin the confirmation phase?
Surely white expects
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RobertJasiek
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Re: Japonese counting
I have not studied the sequences but you just may not ignore A7 in your study. If it should be futile, you must prove it. Making assumptions is not applying the rules.
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Gérard TAILLE
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Re: Japonese counting
Yes Robert. In my post viewtopic.php?p=266383#p266383 I try to explain why this move black in A7 loses one point due to a cycle with one more black prisoner.RobertJasiek wrote:I have not studied the sequences but you just may not ignore A7 in your study. If it should be futile, you must prove it. Making assumptions is not applying the rules.
OC we must apply the rules and it is really my question with my example.
I suggest finishing the game by:
pass pass passand white wins by 10 points.
but because I am not completly sure of my understanding of the rule I ask to the experts if this sequence and this count is really the best result for both.
You see the curiosity here? In normal play white do not need to add a move to kill black stones, but, due to the confirmation phase, white must play three moves before the end of the game in order to declare the black stones really dead
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Mike Novack
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Re: Japonese counting
First of all, I object to the "simplification". Totally different problem. In the first example, under consideration is whether black can prevent the large white group from becoming unconditionally alive, because if so, it's all over(white can fill the upper left ko(s) and black has no ko threats after the one to live on the top is used.
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Gérard TAILLE
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Re: Japonese counting
It is not clear to me what you mean here by "unconditionally alive". this wording make sense if it exists a rather unknown environment typically with potential ko threats. Here all the board is known and we know it does not exist any ko threat.Mike Novack wrote:First of all, I object to the "simplification". Totally different problem. In the first example, under consideration is whether black can prevent the large white group from becoming unconditionally alive, because if so, it's all over(white can fill the upper left ko(s) and black has no ko threats after the one to live on the top is used.
In my first example the black group at the top is dead. The problem is not to prove black stones are dead but rather to find the sequence which gives the best result.
As I said before my example is not that efficient because after: I am worried by the dame at "a".
Because of that I have to improve the position. The following one is far better:
What is the best sequence for both?
If I am not wrong there are a strong relationship with the following position I proposed:
Re: Japonese counting
I think in the simpler position B don't want to pass since then W can pass too and have no problems (B dead). B needs to throw in once to force W to capture in the main game (costing him points).
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kvasir
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Re: Japonese counting
I thought this was a question if white needs to play zero, one or two moves on the inside. For example something like this:
Or if white just passes if black can force white to play the last move (and possibly force white to play the last move twice in exchange for black passes).
For example:
...and this position is starting to get similar to the second position by Gérard. Possibly the players fills the liberties directly or cycle the ko while filling the liberties, and white always refuses to play extra moves on the inside.
As far as I can see this is an interesting ko study that doesn't necessarily have anything to do with specific rule differences, in the endgame white may get off easily if there is no penalty for finishing the ko but similar situations happen in middle game kos were white may find it difficult to finish the ko immediately. Basically, it appears to be a ko situation in which white can clearly win a capturing race by making an eye, but if white refuses to finish the ko he can lose the advantage because the ko can potentially become direct for black to capture.
Or if white just passes if black can force white to play the last move (and possibly force white to play the last move twice in exchange for black passes).
For example:
...and this position is starting to get similar to the second position by Gérard. Possibly the players fills the liberties directly or cycle the ko while filling the liberties, and white always refuses to play extra moves on the inside.
As far as I can see this is an interesting ko study that doesn't necessarily have anything to do with specific rule differences, in the endgame white may get off easily if there is no penalty for finishing the ko but similar situations happen in middle game kos were white may find it difficult to finish the ko immediately. Basically, it appears to be a ko situation in which white can clearly win a capturing race by making an eye, but if white refuses to finish the ko he can lose the advantage because the ko can potentially become direct for black to capture.
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Cassandra
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Re: Japonese counting
Just returned from walking the labrador. His name is Honte 
So ...
is alive, as it cannot be captured, even if White moves first.
are all dead, as they can be captured.
is alive, as it cannot be captured, even if Black moves first.
@ Gérard: White should NOT pass her first move in the Nihon Kiin 1989 Rules status confirmation!
So ...
is alive, as it cannot be captured, even if White moves first. are all dead, as they can be captured. is alive, as it cannot be captured, even if Black moves first.@ Gérard: White should NOT pass her first move in the Nihon Kiin 1989 Rules status confirmation!
The really most difficult Go problem ever: https://igohatsuyoron120.de/index.htm
Igo Hatsuyōron #120 (really solved by KataGo)
Igo Hatsuyōron #120 (really solved by KataGo)
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Gérard TAILLE
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Re: Japonese counting
Kvasir, your analysis is exactly what I had in mind 
and, due to this dame, I cannot get the result I expected and this sequence was unexpected for me.
In order to avoid the unexpected sequence mentionned at the beginning of this post I proposed a slight change in the initial position.
My modified position is the following:
Now the expected sequence is and we reach a position identical to the simplication I proposed.
I will try to analyse this simpler position in an other post, and please try to take into account only my modified position.
That's true. When I built the problem I just forget to take into account the damekvasir wrote:I thought this was a question if white needs to play zero, one or two moves on the inside. For example something like this:
and, due to this dame, I cannot get the result I expected and this sequence was unexpected for me.That is the sequence I expected
In order to avoid the unexpected sequence mentionned at the beginning of this post I proposed a slight change in the initial position.
My modified position is the following:
Now the expected sequence is and we reach a position identical to the simplication I proposed.
I will try to analyse this simpler position in an other post, and please try to take into account only my modified position.
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Gérard TAILLE
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Re: Japonese counting
OK Jann, let's see what happens if both players pass in the position above and here is really the rule interpretation issuejann wrote:I think in the simpler position B don't want to pass since then W can pass too and have no problems (B dead). B needs to throw in once to force W to capture in the main game (costing him points).
I imagine the following dialog:
White : your black stones at the top are dead
black : no, if I you do not add at least one move, they are living. IOW if you want to kill them you have to resume the game and add at least one move.
white : no I do not want to add moves (because I will lose points).
black : OK in that case we enter the confirmation phase. Because you refuse to add a move that means you consider black stones are dead even if it is black to play right?
White : yes
Black : in that case I start the confirmation phase and you will try to kill me, correct?
White : yes, let's go
and the cycle will go for ever. Does that prove that white cannot kill black stones? That is the point.