Game2by2

This app helps you discover Nash equilibria (mutual best responses) of 2x2 normal form games. It is not an equilibrium solver, however - you need to know where to look.

Select a pre-defined game from three classes (dominance solvable, coordination, and all other games, including ones with infinitely many mixed equilibria), or pick randomly-generated payoffs. The payoff entries are editable, so you can make up your own game as well. Use mixing sliders to control the players’ strategies. The expected payoff of a player’s best response is highlighted in red next to the best-reply strategy row or column.

Press the button “Is it Nash?” to see if you have found a Nash equilibrium. Two additional buttons, “RowMix” and “ColMix,” which set Row’s mixing so that Column is indifferent, and vice versa, may help you find mixed Nash equilibria. Another button highlights pure-strategy best-reply payoffs within the game matrix itself. Clicking on “Hint” presents information about the game currently displayed.

A "Help" button in the top-right corner shows more detailed instructions and discusses ideas to take-away from this app.

Send comments to peter.eso@economics.ox.ac.uk. Thanks to Renana Heller for her help in coding.