Beginner Exercise 140 / Solution

Sub-page of BeginnerExercise140


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.

White dumpling.  

A connection at W4 is highly undesirable for White. After B5, the ko becomes a direct ko, and the White group is extremely heavy.

Direct ko.  

The descent at W2 is not good too, as it leads to a direct ko too.

SilverHawk: Why not B3 at a? White cannot approach on either side due to shortage of liberties, and if White ever captures the marked stone, Black can play b to put White in atari.

fractic; B3 at a captures the two white corner stones but it lets the other 4 white stones off the hook.



The atari at B1 is a failure. Instead of capturing at a, White can descend at W2 and there is nothing else Black can do.


The atari at B1 here does not work either. The key move for White is W4, which prevents the ko.


The following discussion is pitched at a slightly higher level than the problem, but it is still revelant to the problem.


Without the black stone at a, W2 can extend and say arigato to Black for the free gift. Obviously White should not play W2 at b otherwise black can play at B2 and thank White instead.


So without Black a, Black should atari at B1. The correct response is W2, regardless of whether there is a Black stone at a. This is probably a IGS 1k* level indicator.

Beginner Exercise 140 / Solution last edited by fractic on June 2, 2017 - 21:04
RecentChanges · StartingPoints · About
Edit page ·Search · Related · Page info · Latest diff
[Welcome to Sensei's Library!]
Search position
Page history
Latest page diff
Partner sites:
Go Teaching Ladder
Login / Prefs
Sensei's Library