Every citizen of South Korea automatically receives a resident registration number with seventh digit of 9, 0, 1, 2, 3, or 4 (indicating as a Korean citizen) when one's parents register one's birth in South Korea.
As of 2016, holders of South Korean passports with overseas residency are now eligible for a resident registration number with seventh digit of 9, 0, 1, 2, 3, or 4 regardless of their permanent resident status.