Beginner Exercise 48 / Solution

Sub-page of BeginnerExercise48

W1 puts a black stone in atari. The only defence for Black is to set up a ko at B2.

Variation 1.  

If B2, White connects underneath at W3. Black is totally dead.

Variation 2.  

Same as variation 1.

Variation 3.  

B2 prevents White from connecting W1 to the exterior stones, but W3 kills Black easily.

Jacob4Jesus: you say W3 kills easily, but doesn't B4 at a secure two eyes?

MrTenuki: No, because B4 at a is self-atari (White will capture at b). Even if Black had an extra outside liberty (which would make W5 at b impossible), White could still fill in at the circled spot to create a dead shape and keep the group dead.

fractic: W3 captures a stone. Let's visualize it with a diagram.

Variation 3.  

fractic: This is the position after W3.


W1 allows B2 to makes two eyes. There is no snapback at W3.


EthrDemon?:Can't W1 force a ko anyway as Black cannot connect at a?

MrTenuki: Nope, there is no ko here:


Black simply sacrifices the marked stone to live.

...and black is alive.  

(In fact, playing out W1-B2-W3-B4 immediately would be wasting two ko threats.)

Beginner Exercise 48 / Solution last edited by stoned on December 17, 2011 - 06:35
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