Human-computer Chess Matches - Mac Hack VI (1966-1968)

Mac Hack VI (1966-1968)

In 1966 MIT student Richard Greenblatt wrote the chess program Mac Hack VI using MIDAS macro assembly language on a Digital Equipment Corporation PDP-6 computer with 16K of memory. Mac Hack VI evaluated 10 positions per second.

In 1967, several MIT students and professors (organized by Seymour Papert) challenged Dreyfus to play a game of chess against Mac Hack VI. Dr. Hubert Dreyfus, a professor of philosophy at MIT, wrote the book What Computers Can’t Do, questioning the computer’s ability to serve as a model for the human brain. He also asserted that no computer program could defeat even a 10-year-old child at chess. Dreyfus accepted the challenge. Herbert A. Simon, an artificial intelligence pioneer, watched the game. He said “It was a wonderful game - a real cliffhanger between two woodpushers with bursts of insights and fiendish plans…great moments of drama and disaster that go in such games.” The computer was beating Dreyfus when he found a move, which could have captured the enemy queen. The only way the computer could get out of this was to keep Dreyfus in checks with its own queen until it could fork the queen and king, and then exchange them. That is what the computer did. Soon, Dreyfus was losing. Finally, the computer checkmated Dreyfus in the middle of the board.

In the spring of 1967, Mac Hack VI played in the Boston Amateur championship winning 2 games and drawing 2 games. Mac Hack VI beat a 1510 United States Chess Federation player. This is the first time a computer won a game in a human tournament. At the end of 1968, Mac Hack VI achieved a rating of 1529. The average rating in the USCF was near 1500.