Beginner Exercise 173 / Solution

Solution 1  

makes two eyes at the bottom. is necessary to prevent a throw-in ko.

Solution 2  

This solution lives too, if White finds the tesuji like in Beginner Exercise 172. This line is about equal to Solution 1 in points but gives Black more ko threats.

Failure

Failure 1: ko  

invites the atari at . White can only live by fighting the ko with .

Failure 2: dead  

here will only result in a false eye after the throw-in at .