Beginner Exercise 140 Solution
Difficulty: Beginner
Keywords: Problem
Solution
![[Diagram]](../../diagrams/5/ad9d78f7088f84c7e50b0a7458aabf8a.png) | Two stage ko. |
The solution to this problem is a two stage ko. If White cannot win this ko, then he can back out with a subsequently.
![[Diagram]](../../diagrams/10/809fafed73871532f7b511cbec6a5cb6.png) | White dumpling. |
A connection at is highly undesirable for White. After , the ko becomes a direct ko, and the White group is extremely heavy.
![[Diagram]](../../diagrams/35/f0e29dc360ebe8b6d0f71c365708e4b8.png) | Direct ko. |
The descent at is not good too, as it leads to a direct ko too.
Failure
![[Diagram]](../../diagrams/2/6ae059f3be6a31d074a164bbd0a29cd7.png) | Failure. |
The atari at is a failure. Instead of capturing at a, White can descend at and there is nothing else Black can do.
![[Diagram]](../../diagrams/21/116d245c99f7055abccdcc6a5bfbc93f.png) | Failure. |
The atari at here does not work either. The key move for White is , which prevents the ko.
Discussion
The following discussion is pitched at a slightly higher level than the problem, but it is still revelant to the problem.
![[Diagram]](../../diagrams/52/0caa24579c6eccdd9e7d1ef427b07907.png) | Discussion. |
Without the black stone at a, can extend and say arigato to Black for the free gift. Obviously White should not play at b otherwise black can play at and thank White instead.
![[Diagram]](../../diagrams/15/08e87bb2cc8a2a94e68d0b8d117667e5.png) | Discussion. |
So without Black a, Black should atari at . The correct response is , regardless of whether there is a Black stone at a. This is probably a IGS 1k* level indicator.
This is a copy of the living page
"Beginner Exercise 140 Solution" at
Sensei's Library.
2004 the Authors, published under the OpenContent License V1.0.
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