And whence came the name "roshambo" for it? I learned Rock Paper Scissors in the 70s but encountered roshambo only in the 90s.

There's a few answers from an old thread here:

http://reddit.com/r/AskHistorians/comments/2mi17d/what_are_the_origins_of_rock_paper_scissors/

As a follow-up, are there historical reasons for paper beating rock?