Face:

Korean Army emblem; denomination;

Text:

구매권 = coupon; 5 불 = 5 dollars;
주월한국군 사령부 = Headquarters of Korean Army in Vietnam;
O⊥HTZ (must be 오불) = 5 dollars;

Back:

Cheomseongdae Observatory; denomination;

Text:

5 불 = 5 dollars; 오 = 5
첨성대 = Cheomseongdae;