Beginner Exercise 42 / Solution

Sub-page of BeginnerExercise42
[Diagram]
Solution  

There is an eye at the 1-1 point?, and a potential eye at the side. W1 is the makuri technique which robs the potential eye. Notice that W1 is exactly the bao chi technique for capturing black+circle except that white+circle is under atari.

[Diagram]
Solution  

To save black+circle, the only move is to capture white+circle at B2. Then W3 pulls out and leaves Black with a false eye at white+circle.


[Diagram]
Failure (B6 at white+circle)  

If W3 is played here, then B4 can capture and live.


[Diagram]
Reference  

From the life-and-death perspective, exchanging W1 with B2 before playing W3 also kills. However, professionals and dan players do not play this way, because such exchanges are often seen as slightly suboptimal, but the reasons why it is slightly loss-making is rather subtle. In this case, two reasons can be offered. Firstly, should the outside White stones get involved in a capturing race such that White needs to capture the Black corner, Black can capture at a, forcing White b, increasing Black's liberties and creating a ko mouth which means potential for trouble. Secondly, Black c becomes a threat to bridge under via a ko. Without the W1 and B2 exchange, there is no potential for Black c to be a sente move.



Beginner Exercise 42 / Solution last edited by 195.171.106.169 on April 16, 2010 - 17:09
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