February 1980 CB8001
Pink and orange string halter and adjustable (?) string tanga.
Ms. Brinkley sits on a sailboat, her back to the camera (1), and her buttocks is not fully visible because she is sitting on them.
Christie Brinkley introduced the tanga in Sports Illustrated five years ago (CB7501), prematurely it turns out, so she tries again. And again next year (CB8101).
Some bikiniologists might argue this species is actually a g-string, given its string sides. The problem with this conclusion is the triangle of fabric in the back.
Annual Swimsuit Issue, Sports Illustrated, February 1980. 1 picture.