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A diagram explaining the outcomes of the game
Another diagram, displaying clockwise from top: scissors, paper, rock, lizard, Spock
The normal form matrix of rock-paper-scissors-lizard-Spock. Rows represent available choices for player 1, columns those for player 2. Numbers in cells show utility (payoff) for player 1, player 2.

Rock-paper-scissors-lizard-Spock is an expansion of the classic selection method game rock-paper-scissors. It operates on the same basic principle, but includes two additional weapons: the lizard (formed by the hand as a sock-puppet-like mouth) and Spock[1] (formed by the Star Trek Vulcan salute). This reduces the chances of a round ending in a tie (from 1/3 to 1/5). The game was invented by Sam Kass with Karen Bryla, as "Rock Paper Scissors Spock Lizard".[2][non-primary source needed]

The game was mentioned in four episodes of The Big Bang Theory. According to an interview with Kass, the series producers did not ask for permission to use the game, but he was later referenced in the episode "The Rothman Disintegration" from the fifth season, for which he thanked them on his website.[3][self-published source?][2]


Each player picks a hand-shape, then all players reveal their choices at the same time. The winner is the one who defeats the others. The rules of rock-paper-scissors-lizard-Spock are:

  • Scissors cut Paper
  • Paper covers Rock
  • Rock crushes Lizard
  • Lizard poisons Spock
  • Spock smashes Scissors
  • Scissors decapitate Lizard
  • Lizard eats Paper
  • Paper disproves Spock
  • Spock vaporizes Rock
  • Rock crushes Scissors

There are fifteen possible pairings of the five gestures (including ties). Each gesture beats two of the other gestures and is beaten by the remaining two. In a tie, the process is repeated until a winner is found. The original rules (rock beats scissors, scissors beats paper, paper beats rock) remain the same.

Guinness Book of World Records[edit]

The current Guinness world record for largest tournament of rock-paper-scissors was completed using rock-paper-scissors-lizard-Spock.[4] The tournament contained 2,950 participants and was achieved by Oomba, Inc. (USA) at Gen Con 2014 in Indianapolis, Indiana, USA, on 17 August 2014.[5]