https://senseis.xmp.net/?ShikatsuMyokiTsumegoSeries76
I understand White can live without any condition but I do not find how white can live if Black can avoid losing the ko fight at "a".
Can anybody help me?
Shikatsu Myoki Tsumego Series
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Gérard TAILLE
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Gérard TAILLE
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Re: Shikatsu Myoki Tsumego Series
After further analysis I think white can save one of her two groups but not both, but OC I am not completly sure.Gérard TAILLE wrote:https://senseis.xmp.net/?ShikatsuMyokiTsumegoSeries76
I understand White can live without any condition but I do not find how white can live if Black can avoid losing the ko fight at "a".
Can anybody help me?
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Kirby
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Re: Shikatsu Myoki Tsumego Series
The solution given on senseis seems fine, does it not?
be immersed
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Gérard TAILLE
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Re: Shikatsu Myoki Tsumego Series
The problem with the solution is that black has not fighted the ko. AssumeKirby wrote:The solution given on senseis seems fine, does it not?
used a ko threat, 
answer the ko threat and 
retake the ko. That way black has gained locally one move which is quite different.-
Cassandra
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Re: Shikatsu Myoki Tsumego Series
One major assumption for local tsume-go is that the rest of the board is empty / that there are no worthwile moves outside the local area shown.
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: Shikatsu Myoki Tsumego Series
Looking at the first page of Shikatsu Myoki Tsumego Series https://senseis.xmp.net/?ShikatsuMyokiTsumegoSeries I see killing, living and Ko problems.Cassandra wrote:One major assumption for local tsume-go is that the rest of the board is empty / that there are no worthwile moves outside the local area shown.
Here it is a living problem and I underderstood living here means living without conditions but may be I am wrong.
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Cassandra
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Re: Shikatsu Myoki Tsumego Series
"Double-ko" is considered "unconditionally alive".Gérard TAILLE wrote:Here it is a living problem and I underderstood living here means living without conditions but may be I am wrong.
If a ko fight were involved, it would have to be a local one.
In the problem in question, White has a local ko threat, but Black does not have any. Therefore, the ko shape will not be still active at the end of the solution sequence.
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: Shikatsu Myoki Tsumego Series
You do not get my point Cassandra. With black I only want to fight the ko at "a", not the others:Gérard TAILLE wrote:https://senseis.xmp.net/?ShikatsuMyokiTsumegoSeries76
I understand White can live without any condition but I do not find how white can live if Black can avoid losing the ko fight at "a".
Can anybody help me?
ko theat answer to ko threat-
Cassandra
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Re: Shikatsu Myoki Tsumego Series
Dear Gérard,Gérard TAILLE wrote:You do not get my point Cassandra. With black I only want to fight the ko at "a", not the others:
I am very well aware of what you wanted to do. But if you are talking about Shikatsu Myoki #76, ...
pass... your desire will end locally as in the diagramme above.
However, if you wanted to study an extended VARIATION of that position (NOT the original TSUME-GO), you should add some kind of precondition that creates a firm connection to other positions on the Go board, and also specifies which value potential external ko threats of both sides have.
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: Shikatsu Myoki Tsumego Series
Cassandra, I confess I have difficulty to understand what is your view, sorry for that.Cassandra wrote:Dear Gérard,Gérard TAILLE wrote:You do not get my point Cassandra. With black I only want to fight the ko at "a", not the others:
I am very well aware of what you wanted to do. But if you are talking about Shikatsu Myoki #76, ...
... your desire will end locally as in the diagramme above.
However, if you wanted to study an extended VARIATION of that position (NOT the original TSUME-GO), you should add some kind of precondition that creates a firm connection to other positions on the Go board, and also specifies which value potential external ko threats of both sides have.
Here is the original position
Here is the beginning of the given solution:
After the sequence above, do you claim white can live without conditions?
If not that means that you agree with me because I just do not say something else.
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Cassandra
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Re: Shikatsu Myoki Tsumego Series
"UNconditional" does not imply that there is no ko involved!
+ + + + + + + + + + + + +
+ + + + + + + + + + + + +
Shikatsu Myoki #76:
creates a SECOND ko shape.
captures the ko at right.
connects, as he does not have any LOCAL ko threat.
recaptures the ko at right.
captures the ko at left.
Double-ko = unconditional life for White.
Q.e.d.
+ + + + + + + + + + + + +
+ + + + + + + + + + + + +
Igo Hatsuyoron #80:
creates a ko shape.
captures the ko.
plays a LOCAL ko threat.
answers.
recaptures the ko.
Black does not have any LOCAL ko threat => White dies in ko. => White is NOT unconditionally dead.
(The ko is disadvantageous for Black, as he has to find the first EXTERNAL ko threat, and White has several LOCAL ko threats remaining.)
+ + + + + + + + + + + + +
+ + + + + + + + + + + + +
Shikatsu Myoki #76:
creates a SECOND ko shape. captures the ko at right. connects, as he does not have any LOCAL ko threat. recaptures the ko at right. captures the ko at left.Double-ko = unconditional life for White.
Q.e.d.
+ + + + + + + + + + + + +
+ + + + + + + + + + + + +
Igo Hatsuyoron #80:
creates a ko shape. captures the ko. plays a LOCAL ko threat. answers. recaptures the ko.Black does not have any LOCAL ko threat => White dies in ko. => White is NOT unconditionally dead.
(The ko is disadvantageous for Black, as he has to find the first EXTERNAL ko threat, and White has several LOCAL ko threats remaining.)
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: Shikatsu Myoki Tsumego Series
I agree till that point. But here, with black to play, I stop playing locally and say:Cassandra wrote:"UNconditional" does not imply that there is no ko involved!
+ + + + + + + + + + + + +
+ + + + + + + + + + + + +
Shikatsu Myoki #76:
creates a SECOND ko shape.
Black does not have any LOCAL ko threat => White lives in ko. => White is NOT unconditionally living.
Don't you agree with that?
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jlt
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Re: Shikatsu Myoki Tsumego Series
To summarize, if I followed correctly your conversation,
1) If there are no ko threats elsewhere, White lives by double ko.
2) If Black has enough ko threats elsewhere, then Black can kill White.
Cassandra calls the conjunction of 1) and 2) "living without condition", while Gérard calls that "living by ko"?
1) If there are no ko threats elsewhere, White lives by double ko.
2) If Black has enough ko threats elsewhere, then Black can kill White.
Cassandra calls the conjunction of 1) and 2) "living without condition", while Gérard calls that "living by ko"?
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Gérard TAILLE
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Re: Shikatsu Myoki Tsumego Series
Yes jlt but, in addition, if Black has enough ko threats elsewhere then the sequence given is not the best one for white. By choosing other moves I think white can save one of her groups.jlt wrote:To summarize, if I followed correctly your conversation,
1) If there are no ko threats elsewhere, White lives by double ko.
2) If Black has enough ko threats elsewhere, then Black can kill White.
Cassandra calls the conjunction of 1) and 2) "living without condition", while Gérard calls that "living by ko"?
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Cassandra
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Re: Shikatsu Myoki Tsumego Series
NO. Not if we talk about TSUME-GO.Gérard TAILLE wrote:Black does not have any LOCAL ko threat => White lives in ko. => White is NOT unconditionally living.
Don't you agree with that?
Your misunderstanding here is similar to the following:
The correct solution of a tsume-go is assumed to contain the strongest attempt of the attacker / the strongest defense of the defender.
For many of these positions -- if encountered in a real game -- you would stop the tsume-go solution sequence in between, in order to play moves in the surrounding that will benefit you in the endgame (e.g. instead of trying the strongest attempt to kill from the inside but fail, and / or to sacrifice stones unnecessarily).
Even with Shikatsu Myoki #76, you might want to play Black 2 at 5, in order to reduce White's corner territory decisively in sente, and be happy with it.
Life-and-death tsume-go are designed for training your attacking and defending techniques in close combat. They are not intended to simulate the decision criteria of a "real" game. With regard to "real" games, many tsume-go solutions must be considered wrong.
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)