Gokyo Shumyo, Section 1, Problem 40 / Solution

[Diagram]
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.

[Diagram]
Main line  
[Diagram]
Continuation 1  

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

[Diagram]
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.

[Diagram]
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.

[Diagram]
Failure 1b  

This results in ko.

[Diagram]
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.

[Diagram]
Alternate play 1b  
[Diagram]
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.

[Diagram]
Failure 2b  
[Diagram]
Failure 2c  

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

[Diagram]
Failure 2d  

Maximising his eye space does not work.

[Diagram]
Failure 2e  

B1 here does not work either.


Go to Problem 41


Gokyo Shumyo, Section 1, Problem 40 / Solution last edited by 138.251.241.132 on July 10, 2009 - 04:43
RecentChanges · StartingPoints · About
Edit page ·Search · Related · Page info · Latest diff
[Welcome to Sensei's Library!]
RecentChanges
StartingPoints
About
RandomPage
Search position
Page history
Latest page diff
Partner sites:
Go Teaching Ladder
Goproblems.com
Login / Prefs
Tools
Sensei's Library