South Korean resident registration number: a six digit birth date, a dash, then a digit saying the century and the sex followed by six more. The date is validated and the first digit after the dash is restricted to one through four, which is what keeps it apart from any other thirteen digit sequence.
Label: KR_RRN
(?<!\w)\d{2}(?:0[1-9]|1[0-2])(?:0[1-9]|[12]\d|3[01])-[1-4]\d{6}(?!\w)The form lists 900101-1234567 as the identifier. → 900101-1234567She registered under 851230-2345678 last year. → 851230-2345678The code 901301-1234567 has no such monthReference 900101-5234567Tags: kr, government-id, identity