“Ask a Korean” tackles the issue of South Korean citizenship. Check out the section on “simplified naturalization”:

1. If one of your parents was a Korean citizen. (Emphasis on “was”. It’s ok if your parent renounced Korean citizenship.)

Hey, I think that includes me! My mom was born in Korea to a Korean woman, so she would’ve been a citizen, right? (She would’ve renounced it as a child when they moved to America.) That’s pretty neat.