Gokyo Shumyo, Section 1, Problem 40 / Solution

Black to live  

B1 is the vital point. It clearly makes one eye at the circled point, and White can't prevent another eye to the left of B1.

Main line  
Continuation 1  

Note what a difference an extra white stone at a would make.

Continuation 2  

Again, an extra stone at a would make the difference.

Once the vital point has been played - B1 in the main line - the rest is not so difficult any more. Finding that point is the main challenge here. Let's have a look at how things can go wrong.

Failure 1a  

One is tempted to cover the two-space gap with a move like B1 here. However, White strikes at the vital point. If B5 at W8, then W6 at B5.

Failure 1b  

This results in ko.

Alternate play 1a  

ChrisR: White can avoid the ko by playing W2 first, then W4. Black's group is dead.

Yohei: Black is not dead - he can make seki as shown below.

Alternate play 1b  
Failure 2a  

ChrisR: Playing at B1 is a failing move, but it is better than playing at 3. Up to W8, this is seki.

Yohei: White won't be so kind. W2 in the following diagram kills.

Failure 2b  
Failure 2c  

Taking the vital point now is too late. W2 kills.

Failure 2d  

Maximising his eye space does not work.

Failure 2e  

B1 here does not work either.

Go to Problem 41

Gokyo Shumyo, Section 1, Problem 40 / Solution last edited by on July 10, 2009 - 04:43
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