Rock paper scissors online

What are the rules of rock paper scissors?

Each player makes one of three shapes at the same time: a fist for rock, a flat hand for paper, or two fingers for scissors. Rock beats scissors, scissors beat paper and paper beats rock. If both players make the same shape, the round is a draw and you play again.

Because every move beats one move and loses to another, no shape is stronger than the others. That balance is what makes the game a fair way to settle small decisions, much like a coin toss with a little more drama.

Can you beat the computer at rock paper scissors?

Not in the long run. The computer chooses rock, paper or scissors completely at random, with a one-in-three chance each, and it never looks at your move or your history. Against an opponent like that, every strategy wins about a third of rounds, loses about a third and draws about a third.

So if you are ahead after twenty rounds, enjoy it, but it is luck. Play a hundred rounds and your scores will usually drift towards an even split. That makes this page useful when two people want an impartial referee: each person plays one round against the computer, and the better result wins.

Do people have patterns when they play each other?

Often, yes, and that is where the strategy in the game really lives. People are poor at being random. Some players avoid repeating a move they just used, and some favour a particular opening. A 2014 experiment with several hundred university students in China reported that winners tended to stick with the move that had just won, while losers were more likely to switch.

These are tendencies, not rules, and a thoughtful opponent can use them against you. If you want to be unpredictable against a friend, the most reliable method is to let chance pick for you; the computer here cannot be read, which is exactly the point.

Using the game to decide things

• Who goes first. A quick round decides the first turn of a board game. For a whole group, the who goes first wheel sets the order in one spin.
• Small chores. Best of three for who unloads the dishwasher.
• Waiting time. A quick match against the computer passes a queue or a car journey, with the score kept for you.
• Teaching probability. Have a class play 30 rounds each, then pool the scores. The combined totals will usually land close to a third each, which is a nice way to show the law of large numbers.

What is rock paper scissors lizard Spock?

It is a popular five-move variant, credited to Sam Kass and Karen Bryla and made famous by the TV sitcom The Big Bang Theory. Lizard and Spock are added so that each move beats two others and loses to two others, which makes draws less common. This page plays the classic three-move game only. To play the five-move version by chance, put the five moves on a decision wheel and spin it for your throw.