Tsumego From Games 15 / Solution
unkx80: Herman has given the correct answer.
![[Diagram]](../../diagrams/25/1ba74916c987034cc2afe2c69187786b.png)
Removing ko options.
Playing at 1 removes any chance of getting into ko. Black cannot play a, since White has one liberty more. If Black plays b, White plays c and vice-versa.