MacHack

MacHack was a chess program, which is considered a milestone in the history of computer chess. It was developed in November 1966 by Richard Greenblatt, a student of Marvin Minsky, MIT.

Greenblatt was inspired by the so-called Kotok - McCarthy program, a 1959-1962 developed at MIT chess program for the mainframe IBM 7090th He wrote the first version of the program in just a week and received for testing four daily hours of computing time on the institute's PDP 6 allocated. Subsequently, numerous bug fixes and additional features incorporated; while the program was over 200 times recompiled. They offered Greenblatt to write his thesis on chess programming, which never came about.

The 16 kilobytes, written in assembly language program could calculate 10 positions per second. Greenblatt implemented 50 heuristics for determining plausible trains. In the first and second half-train looking 9 trains were 15, in the third and fourth halfmove investigated. The program usually reached a search depth of five half moves in games. As the first program MacHack had a opening book containing more than 5,000 half-moves and was created by Larry Kaufman. In addition it could save 32,000 positions in a hash table and draw in the evaluation of positions that came through diverter about, it. The major weakness of the program was in the final. Since it assessed the significance of the center high, remote Yeomanry were regularly underestimated.

In January 1967 MacHack VI became the first chess program to a chess tournament, the amateur championship of Massachusetts. It achieved a draw from five games and received a rating of 1239th

At a demonstration at MIT, the program was able to win a game against the known as a critic Hubert Dreyfus artificial intelligence. Eyewitness Herbert Simon described the event as " wonderful match between two blocks sliders " ( the English word is wood pusher a more familiar term for weak players ).

Dreyfus - 1.e4 e5 2.Nf3 Nc6 MacHack Nf6 4.Nc3 Bc5 5.d3 0-0 3.Lc4 6.Sg5 Sa5 7.Ld5 c6 8.Lb3 Sxb3 9.cxb3 h6 10.Sh3 d5 11.exd5 Bg4 12. f3 Lxh3 13.gxh3 Nxd5 14.Sxd5 Qxd5 15.Ld2 Dxd3 16.b4 Be7 17.Tg1 e4 18.fxe4 Lh4 19.Tg3 Lxg3 20.hxg3 Dxg3 21.Ke2 h5 Dxh3 22.Dg1 23.Lc3 g6 24.Df2 h4 25.Df6 dG4 26.Kd2 Tad8 27.Kc2 dxe4 28.Kb3 DE6 29.Dxe6 fxe6 30.Th1 Tf4 31.Le1 Tf3 32.Ka4 h3 33.b5 34.b4 cxb5 Td4 35.Kxb5 Ta3 36.Kc5 Td5 37. KC4 b5 #

In the spring of 1967 MacHack won in a tournament for the first time a match against a player with rating of. Overall, the program played this year 18 tournament games against human players, scoring 3 wins and 3 draws in 12 defeats. It was then appointed an honorary member of the United States Chess Federation. 1969 reached MacHack a rating of 1529th

The program was ported to the PDP-10 faster and was available on several time-sharing computers. It took part in chess tournaments until 1972. In 1977, the then played otherwise inactive world champion Bobby Fischer three games against MacHack VI, where the program had no chance. One of the games was as follows:

Fischer - 1.e4 e5 2.f4 MacHack exf4 3.Lc4 d5 Nf6 5.Nc3 Bb4 4.Lxd5 6.Sf3 0-0 7.0-0 Bd6 9.d4 g5 Nxd5 8.Sxd5 10.Sxg5 Dxg5 11.e5 LH3 12. Tf2 Lxe5 13.dxe5 c6 14.Lxf4 Dg7 15.Sf6 Kh8 16.Dh5 Rd8 17.Dxh3 Sa6 18.Tf3 Qg6 19.Tc1 KG7 20.Tg3 Th8 21.Dh6 #