Stage 1: Instructions

Player 1 will move first, choosing between “In” or “Out.” If Player 1 chooses “Out,” then the game ends, with Player 1 earning 100 and Player 2 earning 600. If Player 2 chooses “In,” then Player 2 learns Player 1’s choice and chooses between “Up” (Player 1 earns 500 and Player 2 earns 100) or “Down” (Player 1 earns −1000 and Player 2 earns −1000).

The game is depicted below: