Beginner Exercise 48 / Solution

Solution.  

puts a black stone in atari. The only defence for Black is to set up a ko at .

Variation 1.  

If , White connects underneath at . Black is totally dead.

Variation 2.  

Same as variation 1.

Variation 3.  

prevents White from connecting to the exterior stones, but kills Black easily.

Jacob4Jesus: you say kills easily, but doesn't at a secure two eyes?

MrTenuki: No, because at a is self-atari (White will capture at b). Even if Black had an extra outside liberty (which would make at b impossible), White could still fill in at the circled spot to create a dead shape and keep the group dead.

fractic: captures a stone. Let's visualize it with a diagram.

Variation 3.  

fractic: This is the position after .

Failure  

allows to makes two eyes. There is no snapback at .

Continuation  

EthrDemon?:Can't force a ko anyway as Black cannot connect at a?