Checkers (1952)

Strachey's program inspired Arthur Samuel to develop his own checkers game in 1952 for the IBM 701 and although the IBM 701 machine on which he developed his Samuel Checkers program was among the most powerful computers of its time, its memory was not sufficient to game out every possible outcome of each move. Samuel got around this limitation by introducing what is now called “alpha-beta pruning,” a scoring system that allowed the program to evaluate the likelihood of winning from certain positions without playing them out to the end of the game. Like a human player, Samuel Checkers looked as many moves ahead as it could and made its decisions from there.

• Release Date: December 31, 1952