25 Cents Military Payment Certificate

Military Payment Certificates were issued to U.S. service personnel stationed overseas as a containment measure — the system was designed to limit black-market conversion of U.S. dollars into local currencies, a persistent problem in Vietnam and elsewhere. Series 641, which covers this note, ran from 1965 to 1968 and was in active use throughout the escalation of American involvement in Southeast Asia.

MPC series changes were executed as surprise "C-Day" conversion events, announced without warning and completed within a single duty day, deliberately freezing out anyone holding certificates illegally. Locals caught holding Series 641 at conversion simply lost their money.