Beginner Exercise 17 / Solution

White creates a ko  

The solution is to hane at ; Black has to play in order to make two eye shapes; the throw-in at then starts the ko. This is a two-stage ko that is favourable for Black - White needs three moves (, a and connect) to resolve it.

(Note on ko rules: In such a throw-in ko, Black can play immediately because it doesn't repeat a past position. White needs to play a ko threat before recapturing at .)

Black's squeamishness punished  

If Black tries to avoid the ko, he'll just die outright.

White's misstep  

If White plays on the top first, Black will just hane and make two eyes (White can't play at a because Black will immediately capture).