Rock, Paper, Scissors

The game seems to originate in hand games from China, likely going back a few thousand years. The trail gets more clear starting around the 17th century when some of these games migrated to Japan and explicit references to them in surviving text. One of those games, in turn, spread from Japan throughout the world in recent times.

There were a myriad of these hand games using a series of hand gestures, sometimes even using various chants. As for the many three hand gesture variants, these are called sansukumi-ken.

As variant of this, the Japanese “mushi-ken” used hand gestures representing a frog, a slug, and a snake. The specific gestures were the thumb as the frog, which defeats the slug. The slug is represented by the pinky finger and defeats the snake. The snake is represented by the index finger and defeats the frog.
The direct ancestor to Rock, Paper, Scissors is the game of jan-ken, which has been played in Japan going back to around the 17th century and uses the Rock, Paper (or cloth), Scissors trio of hand gestures we are all familiar with.

Up until relatively recently, these games were primarily used as drinking games, particularly popular at Chinese and Japanese brothels. Yakyūken is a version of Rock, Paper, Scissors played in Japan that is the game of choice for the hand gesture equivalent of strip-poker.
It then spread to the world between the 1920s and the 1950s. For example, some of the earliest references of the game outside of Japan include one account in France in 1927 where it was called “chi-fou-mi”, or another in Britain in 1924 where it was called “zhot”.

As to why this particular hand gesture game caught on in the wider world when so many others did not, it is speculated that it is because it is one of the simplest to understand and play, as well as that it makes a very effective and seemingly random way to settle a dispute or decide something between two individuals.

Fast-forwarding to today, the game has even become a competitive sport with various organizations formed in different countries. For example, in 2002, the brothers Walker formed the World RPS Society and formalized the rules for international competition. They held the “Rock, Paper, Scissors World Championships” in Toronto every year from 2003 to 2009, which was televised on Fox Sports Net at one point.

If someone wins, they are more likely to make the same choice the next time. If they lose, however, they are likely to choose the next item in the sequence from the one they just lost with. So, if one loses with rock, they are likely to choose paper the next time. If they lose with paper, they are more likely to throw scissors the next time. Thus, they are picking the thing that they just lost to.

Players who repeat the same sign twice are extremely unlikely to throw the same sign a third time, allowing you to improve your odds slightly by ruling that one out as something they will pick in most cases. Thus, if they throw scissors twice, your next throw should be paper, as they are likely to choose either paper or rock, improving your odds of a tie or win.

Incidentally, In America, another name for Rock, Paper, Scissors is “Rochambeau.” The commonly held story is that it is from a French general by the name of Jean-Baptiste Donatien de Vimeur de Rochambeau.