An international student asked. "Teacher, why do banks, phone shops, and hospitals all keep asking to see my card?" As a Korean, I had never thought of that as strange. ## A Life Tied to a Single Number In Korea, every person has a number. For Koreans it's the resident registration number, and for foreigners who stay long-term it's the alien registration number. Your bank account, mobile phone, and health insurance are all tied to this number. Banks require that an account be opened in your own name. Because phones are sometimes activated under someone else's name and used for fraud, identity checks for them are strict. At the hospital, too, when you hand over your card, your insurance records link up right away. That's why this card is a key that shows "who I am" all at once. ## What it costs without the card Getting the card takes time and effort. You have to go to an immigration office, submit an application, gather your documents, and pay a fee too. But not having it costs you more. Without a bank account, it's hard to pay rent or receive your salary. Without a mobile phone, all sorts of verifications get blocked too. If you go to the hospital without insurance, the medical bills can become a heavy burden. ## What to do right away If you plan to stay more than 90 days, find out how to register as early as you can after you arrive. Appointment bookings, required documents, fees, and processing times can change. Be sure to check on HiKorea (hikorea.go.kr) or at your nearest immigration office. Keep your passport with you until your card is issued. Once you have your card, don't send photos of the front and back to others carelessly.