It was submitted by Anatol Rapoport, and known as “TIT FOR TAT” (TFT) that “cooperates on the first move, and subsequently echoes (reciprocates) what the other player did on the previous move”.
The results of the first tournament were analyzed and published, and a second tournament held to see if anyone could find a better strategy, but TFT won again. Axelrod analyzed the results, and
made some interesting discoveries about the nature of cooperation in these scenarios, which he describes in his book (Axelrod, 1984).