This rule begins with cooperation and tit for tat. However, when the other player finishes his second run of defections, an extra punishment is instituted, and the number of punishing defections is increased by one with each run of the other’s defections. The other player is given a fresh start if he is 10 or more points behind, if he has not just started a run of defections. if it has been at least 20 moves since a fresh start, if there are at least 10 moves remaining, and if the number af defections differs from a 50-50 random generator by at least 3.0 standard deviations. A fresh start involves two cooperations and then play as if the game had just started. The program defects automatically on the last two moves.