Best First Move in Rock Paper Scissors

Ask for the best first move and you will hear 'rock, because it is aggressive' or 'paper, because everyone throws rock.' Both lines are folk wisdom about humans, not about the rules.

Against a uniform random opponent

Every opening is equal. Expected value is a draw. Changing your opening does not raise your win rate.

Against people

Several casual surveys — not Duetly's dataset yet — find rock as a common opener, especially among people who have not thought about the game. If you believe your opponent is in that group, paper is a reasonable first throw. If you believe they also read this sentence, it is not.

A less cute answer

Pick before the page loads so you are not reacting to the buttons. Then ignore your own superstition in round 2. The first throw is the one you should care about least in a best-of-5. Start a match and spend your attention on round 3, when habits show.