Before you finish typing a card number, the checkout knows the network, the issuing bank, the country, and whether it's debit, credit, or prepaid — all from the BIN. Type a few digits and watch it happen.
Issuer Identification Numbers are assigned under ISO/IEC 7812. The first digit is the industry, the first 6–8 digits are the issuer — and the carve-outs tell the history of the card business.