I previously thought Korea worked this way bit it seems it's a lot more puzzling than I thought. https://overseas.mofa.go.kr/no-en/brd/m_21237/view.do?seq=33#:

I previously thought Korea worked this way bit it seems it's a lot more puzzling than I thought. https://overseas.mofa.go.kr/no-en/brd/m_21237/view.do?seq=33#:~:text=When%20a%20Korean%20baby%20is,you%20were%20born%20in%202000 https://overseas.mofa.go.kr/no-en/brd/m_21237/view.do?seq=33....