Since Black wins against the strongest white defence we could find so far, that can only mean that W has an even stronger defence somewhere, right? (Unless Black is greedy and wants a better score than B+0,5. But that's hard for me to believe; the result so far and the balance of the furikawaris give a impression of perfection to me...)dany wrote: The current solution has 67 moves. The real solution has over 100 moves
The most difficult yose problem
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jmeinh
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Re: The most difficult yose problem
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Gérard TAILLE
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Re: The most difficult yose problem
Oops, does that mean it is possible for white to choose a far longer defense? It is more and more unbelivable. Could you give us another hint? Maybe where white can make another choice?dany wrote: The current solution has 67 moves. The real solution has over 100 moves
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dany
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Re: The most difficult yose problem
The same ko but with more ko threatsGérard TAILLE wrote:Oops, does that mean it is possible for white to choose a far longer defense? It is more and more unbelivable. Could you give us another hint? Maybe where white can make another choice?dany wrote: The current solution has 67 moves. The real solution has over 100 moves
Hint 3. In the position are more ko threats. But white and also black must prepare them...beforehand
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Re: The most difficult yose problem
Is it a good improvment ? (I still need some more work to continue from this new idea)dany wrote:The same ko but with more ko threatsGérard TAILLE wrote:Oops, does that mean it is possible for white to choose a far longer defense? It is more and more unbelivable. Could you give us another hint? Maybe where white can make another choice?dany wrote: The current solution has 67 moves. The real solution has over 100 moves
Hint 3. In the position are more ko threats. But white and also black must prepare them...beforehand
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Re: The most difficult yose problem
dany wrote: The same ko but with more ko threats
Hint 3. In the position are more ko threats. But white and also black must prepare them...beforehand
Yes, 24 and 25 prepare ko threatsGérard TAILLE wrote: Is it a good improvment ? (I still need some more work to continue from this new idea)
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Gérard TAILLE
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Re: The most difficult yose problem
What I have not yet discovered is how to use the white marked stone. I guess I can build a damezumari on the black marked group but it is not clear if I have to search an atari or a seki. I continue to search. In any case it is quite interesting.dany wrote:dany wrote: The same ko but with more ko threats
Hint 3. In the position are more ko threats. But white and also black must prepare them...beforehandYes, 24 and 25 prepare ko threatsGérard TAILLE wrote: Is it a good improvment ? (I still need some more work to continue from this new idea)
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Cassandra
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Re: The most difficult yose problem
I would like to suggest this 
.
Black's
does not have any benefit for the ensuing sequence after the used move at A, so it is unlikely that A is the correct choice here.
.Black's
does not have any benefit for the ensuing sequence after the used move at A, so it is unlikely that A is the correct choice here.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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Cassandra
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Re: The most difficult yose problem
Just another matter of shape:
Before the ko starts, White would like to have created another formation at the top (
), reducing Black's string to the left to only three liberties.
Before the ko starts, White would like to have created another formation at the top (
), reducing Black's string to the left to only three liberties.
Last edited by Cassandra on Sun Feb 13, 2022 12:02 pm, edited 1 time in total.
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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Cassandra
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Re: The most difficult yose problem
Just another deep "feeling":
I can't really believe that the correct solution sequence should contain so many White passes.
Therefore, I do not "feel" that Black will play
at 
in the lower right corner.
Additionally, I do not "feel" that White would start the ko-fight, as this measure would cost her some Black stones in her prisoners lid.
I can't really believe that the correct solution sequence should contain so many White passes.
Therefore, I do not "feel" that Black will play
at in the lower right corner.Additionally, I do not "feel" that White would start the ko-fight, as this measure would cost her some Black stones in her prisoners lid.
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: The most difficult yose problem
After we saw that this 
is losing.
What about the move below:
and now if and white has gained one point
and if black has lost one ko threat
we saw that this is losing.What about the move below:
and now if and white has gained one point
and if black has lost one ko threat
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Re: The most difficult yose problem
In the second diagram, Black could remove the D4 ko threat before starting the ko fight, and also the indirect ko threat on G7 (assuming that W has set 28 to 29, which seems more efficient to me). This 2-point loss should be compensated by connecting G2.Gérard TAILLE wrote: After
What about the move below:
and now if and white has gained one point
and if black has lost one ko threat
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dany
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Re: The most difficult yose problem
jmeinh wrote:In the second diagram, Black could remove the D4 ko threat before starting the ko fight, and also the indirect ko threat on G7 (assuming that W has set 28 to 29, which seems more efficient to me). This 2-point loss should be compensated by connecting G2.Gérard TAILLE wrote: After
What about the move below:
and now if and white has gained one point
and if black has lost one ko threat
interesting moveboth black and white lost 4 points and 1 ko threat. so black still win
or
black lost 3 points and white lost 4 points. both lost 1 ko threat. so black still win
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Gérard TAILLE
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Re: The most difficult yose problem
Very convincing explanation. Thank you Dany and Jmeinhdany wrote:jmeinh wrote:In the second diagram, Black could remove the D4 ko threat before starting the ko fight, and also the indirect ko threat on G7 (assuming that W has set 28 to 29, which seems more efficient to me). This 2-point loss should be compensated by connecting G2.Gérard TAILLE wrote: After
What about the move below:
and now if and white has gained one point
and if black has lost one ko threat
both black and white lost 4 points and 1 ko threat. so black still win
or
black lost 3 points and white lost 4 points. both lost 1 ko threat. so black still win
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Gérard TAILLE
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Re: The most difficult yose problem
White can reach 102 moves but by losing one point => black wins by 1.5 points in this variation:jmeinh wrote:If we want to use the white stone on the right side, how about this?
oops... not quite 100 moves, but pretty close!