"You might think that "Rock, Paper, Scissors" is just a kid's game, but the fact is that some people take it very seriously. Too seriously, I'm starting to think. As is the case with most games that are primarily played by children, the exact time and place when the game was invented are unknown. There are theories, however. Geez, are there theories.
First, for the three people in the country who may be unfamiliar with the game, a short description:
"Rock, Paper, Scissors," also known as roshambo (I'll get to the reason for this presently), has been around for a long time, and most civilized people have at least a passing knowledge of the game. It is most often used to decide small matters between two people--who'll drive to the burger joint, who has to take out the garbage, etc.--but it can also be played to decide larger matters, as part of a tournament, or simply as a diversion.
The basics of the game consist of each player shaking a fist a number of times ("priming") and then extending the same hand in a fist ("rock"), out flat ("paper"), or with the index and middle fingers extended ("scissors"). Each of these is referred to as a throw, and which one wins is dependent upon the opponent's throw--paper wins against rock ("paper covers rock"), rock wins against scissors ("rock crushes, or dulls, scissors"), and scissors wins against paper ("scissors cut paper"). If each player makes the same throw, the round is a stalemate, and must be replayed.
Back in January of this year, someone in the Edmonton area had the same question as you've posed, Scott. The woman apparently was unfamiliar with our illustrious Unca Cecil, so instead of coming to the Straight Dope, she called local radio station CBC 740 AM, where morning host Ron Wilson runs a segment called "The Good Question" each morning. Mr. Wilson went to the same source that I went to for information, namely the World Rock Paper Scissors Society (hard to believe, ain't it?). The telephone interview that he conducted with a Society member by the name of Doug Walker, which I'll summarize here, can be found in its entirety at edmonton.cbc.ca/radio1/edm-am/goodques.html.
Mr. Walker claims that the earliest known written record of the game is from around 200 BC in Japan, where the game was (and is) referred to as "Jan-Ken." I found the existence of the Japanese version of the game corroborated elsewhere, although I have yet to find any corroboration for the 200 BC claim. Mr. Walker goes on to suggest that the game migrated to Europe in or by the mid-1700s, where it for some reason came to be associated with one Jean Baptiste Donatien de Vimeur, Comte de Rochambeau. If this name brings back unsettling memories of high school history, it is because Jean Baptiste was none other than the French general who was sent to command an army in support of George Washington during the American Revolution. Why this game came to be associated with the "Count of Rochambeau" is a mystery, but it certainly calls into question the means by which Washington secured Cornwallis's surrender in Yorktown. In any case, it does explain the name often used for the game, namely "rochambeau," or, more commonly, "roshambo."
This isn't the only theory about the origins of the game. A guy who goes by the handle "Master Roshambollah" on the bulletin board of the World RPS Society website (www.worldrps.com) lists two common theories about the origins of the game besides "the Asian theory": "the African theory," which relies on the creation of tools by early man in much the same way as the Asian theory, and "the European theory," in which RPS was either an early Scandinavian pastime which spread to Europe, or a traditional Celtic game that spread to Portugal and then to Europe. The European theory is advanced by another poster on the board who calls himself "Joao V de Portugal": "Current research undertaken at the University of Lisbon by Baltasar Rui Delfim, soon to be published in Nature and Time, has shown that the origins of the game of Paper, Scissors and Rock (Pihedra, Papelsh e Tijhera) can be attributed to Celtic settlers in the northern regions of Portugal, near the Portuguese/Spanish border, around the 6th century BC. . . . It is believed that the game spread to the rest of Portugal in the 3rd century BC and to the rest of the Spanish peninsula over the next 50 years. Roman invasion of Hispania in the 1st century AD made the game popular in Gallia and Italia. However, the Romans did not introduce the game to the UK because they believed that the game could make the UK colonies rebel against the Senate and it was not until the Portuguese armada of 350 AD came to England that the game was properly introduced in Britannia."