The Bernstein Program

The Bernstein Program is the earliest known chess game that implemented the complete rule set. The game examines two levels of moves, but unlike earlier chess games doesn't try out every possible move but only the seven most plausible moves. After determining what the most plausible moves are the game uses static factors and minimaxing to determine the best move. Running on the IBM 704 computer the program took about eight minutes to determine its move and never managed to defeat a human opponent.