Beginner Exercise 137 / Solution

Pick a Ko  

Now, black has a choice between securing the left and the right. If he secures the right, white can make a ko on the left, and likewise, if he secures the left, play on the right as follows:

unkx80: This sequence from to is my intended solution, because white will take the ko first.

letsrock: The solution might not work in all cases. If fills at and black wins the ko on the left he can also secure the left group with b.

xela: The solution "works" regardless of who wins the ko. Remember that if black wins the ko, it means that black has ignored a ko threat somewhere else. There are two outcomes: either white wins the ko and captures some stones shown on the diagram, or white loses the ko and takes profit in a different part of the board. Either outcome is better for white than the failure diagram below.

Failure  

If white plays this way, then all of black's stones live without black needing to ignore any ko threats.