The number consists of 13 digits. The first six digits are the date of birth in year,
month, day order. The seventh digit identifies the sex of the person; a male is 1
and a female is 2. Digits eight through 12 indicate the region of Korea in which the
person was born. The final digit is a “check digit” that mathematically confirms the
validity of the preceding 12 digits.
For foreign nationals, digits eight through thirteen identify the year of registration
and the Registration Office.