It seems to me that Black can win the ko while also answering in the lower left, winning by over 10 points.
In terms of reading it out, we might first ask, "What about the seki?" Something like the first diagram will follow, but White ends up winning by 2.5, I think. This is where I would start reading and I think it is fairly straight forward. After all, if it works, we do not have to figure out the rest. Unfortunately it isn't enough.
So Black must play the ko. The diagram below we might consider the base case. Black has a ko threat at 7, which offsets White ko threat at 4. After 9, White has no further ko threats and cannot prevent Black from capturing the top right, winning by over 10 points. I could read this out. However, see the next diagram.
What if White plays 4 to eliminate Black's ko threat? Black has an interesting resource here. Connecting between 3 and 1 creates a double ko that White cannot win. White can get the rest of the yose, but still loses by over 10 points. I could not read out this double ko in my head. I only saw it using a board. So I initially assessed that White could win no matter what Black played.
Subtilities for ko threats handling
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ez4u
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Re: Subtilities for ko threats handling
Dave Sigaty
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dany
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Re: Subtilities for ko threats handling
8 wrong moveez4u wrote:It seems to me that Black can win the ko while also answering in the lower left, winning by over 10 points.
So Black must play the ko. The diagram below we might consider the base case. Black has a ko threat at 7, which offsets White ko threat at 4. After 9, White has no further ko threats and cannot prevent Black from capturing the top right, winning by over 10 points. I could read this out. However, see the next diagram.
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Gérard TAILLE
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Re: Subtilities for ko threats handling
No but surely I am interested. Do you have a link available?dany wrote:Have you heard about the real yose-and-ko monstercreated by Cho U?
I agree entirely with you. By looking again and again at this position (thank you for this advice) I have greatly improved my counting process by using a quite simple rigorous method. In addition I see some progress in vizualisation though it is a little more difficult for me.dany wrote:Such problems are a good way to improve your reading skills. if you look at this position again and again, then over time, the calculation will become easier. My second attempt 7 min
Oops it is very high isn't it? Certainly your are right if the goal is really (that was my question indeed) to find the best sequence. If now the problem is only to find the move to play in a real game then it is different because you can easily eliminate losing moves like the seki variation or a losing ko fight.Knowing you are 4 dan, do you think such endgame can be solved in real game by a very strong amateur?dany wrote:I think 6-7 dan can do it in a real game
Fine. I agree with you.dany wrote:BTW what is the result of the game according to your analyse?dany wrote:B+0.5
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ez4u
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Re: Subtilities for ko threats handling
Cool! Even with a board, I missed that. So White can capture around the outside while Black is capturing the White stones that Black ataris with 7. This is exactly the type of thing that I cannot imagine in my head. It is a step too far for my visualization capabilities.dany wrote:8 wrong moveez4u wrote:It seems to me that Black can win the ko while also answering in the lower left, winning by over 10 points.
So Black must play the ko. The diagram below we might consider the base case. Black has a ko threat at 7, which offsets White ko threat at 4. After 9, White has no further ko threats and cannot prevent Black from capturing the top right, winning by over 10 points. I could read this out. However, see the next diagram.
Dave Sigaty
"Short-lived are both the praiser and the praised, and rememberer and the remembered..."
- Marcus Aurelius; Meditations, VIII 21
"Short-lived are both the praiser and the praised, and rememberer and the remembered..."
- Marcus Aurelius; Meditations, VIII 21
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Gérard TAILLE
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Re: Subtilities for ko threats handling
Yes Ez4u I was very satisfied to discover this hidden exchange. In addition you will find that the remaining sequence is still not obvious due to the special configuration of the small yose in the middle of the board. You have to recognize that all black moves are unique against the best white defense.ez4u wrote:Cool! Even with a board, I missed that. So White can capture around the outside while Black is capturing the White stones that Black ataris with 7. This is exactly the type of thing that I cannot imagine in my head. It is a step too far for my visualization capabilities.dany wrote:8 wrong moveez4u wrote:It seems to me that Black can win the ko while also answering in the lower left, winning by over 10 points.
So Black must play the ko. The diagram below we might consider the base case. Black has a ko threat at 7, which offsets White ko threat at 4. After 9, White has no further ko threats and cannot prevent Black from capturing the top right, winning by over 10 points. I could read this out. However, see the next diagram.
BTW white can force a longer defense by beginning with:
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dany
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Re: Subtilities for ko threats handling
The most difficult yose problemGérard TAILLE wrote:No but surely I am interested. Do you have a link available?dany wrote:Have you heard about the real yose-and-ko monster
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Gérard TAILLE
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Re: Subtilities for ko threats handling
Solution of the problem; congratulation for those who managed to solve it.
Against the best white defense all black moves are unique to win.
Against the best white defense all black moves are unique to win.