Early Chess Programs at MIT
1957–1958	routines by John McCarthy John McCarthy (computer scientist) John McCarthy was an American computer scientist and cognitive scientist. He coined the term "artificial intelligence" , invented the Lisp programming language and was highly influential in the early development of AI.McCarthy also influenced other areas of computing such as time sharing systems...  and Paul W. Abrahams	IBM 704 IBM 704 The IBM 704, the first mass-produced computer with floating point arithmetic hardware, was introduced by IBM in 1954. The 704 was significantly improved over the IBM 701 in terms of architecture as well as implementations which were not compatible with its predecessor.Changes from the 701 included...
1959–1962	Kotok-McCarthy Kotok-McCarthy Kotok-McCarthy also known as was the first computer program to play chess convincingly. It is also remembered because it played in and lost the first chess match between two computer programs.-Development:...	IBM 7090 IBM 7090 The IBM 7090 was a second-generation transistorized version of the earlier IBM 709 vacuum tube mainframe computers and was designed for "large-scale scientific and technological applications". The 7090 was the third member of the IBM 700/7000 series scientific computers. The first 7090 installation...
1965–1967	The Greenblatt Richard Greenblatt (programmer) Richard D. Greenblatt is an American computer programmer. Along with Bill Gosper, he may be considered to have founded the hacker community, and holds a place of distinction in the Lisp and the MIT AI Lab communities.-Childhood:...  program (Mac Hack)	DEC Digital Equipment Corporation Digital Equipment Corporation was a major American company in the computer industry and a leading vendor of computer systems, software and peripherals from the 1960s to the 1990s...  PDP-6 PDP-6 The PDP-6 was a computer model developed by Digital Equipment Corporation in 1963. It was influential primarily as the prototype for the later PDP-10; the instruction sets of the two machines are almost identical.The PDP-6 was DEC's first "big" machine...

Mac Hack is a computer chess

Computer chess

Computer chess is computer architecture encompassing hardware and software capable of playing chess autonomously without human guidance. Computer chess acts as solo entertainment , as aids to chess analysis, for computer chess competitions, and as research to provide insights into human...

 program written by Richard D. Greenblatt

Richard Greenblatt (programmer)

Richard D. Greenblatt is an American computer programmer. Along with Bill Gosper, he may be considered to have founded the hacker community, and holds a place of distinction in the Lisp and the MIT AI Lab communities.-Childhood:...

. Also known as Mac Hac and The Greenblatt Chess Program, it was developed at the Massachusetts Institute of Technology

Massachusetts Institute of Technology

The Massachusetts Institute of Technology is a private research university located in Cambridge, Massachusetts. MIT has five schools and one college, containing a total of 32 academic departments, with a strong emphasis on scientific and technological education and research.Founded in 1861 in...

. Mac Hack VI was the first chess

Chess

Chess is a two-player board game played on a chessboard, a square-checkered board with 64 squares arranged in an eight-by-eight grid. It is one of the world's most popular games, played by millions of people worldwide at home, in clubs, online, by correspondence, and in tournaments.Each player...

 program to play in human tournament conditions, the first to be granted a chess rating, and the first to win against a person in tournament play.

Its name comes from Project MAC ("Multi-Level Access Computer" or "Machine-Aided Cognition") a large sponsored research program located at MIT. Over time, it became a hack in the sense of Hackers: Heroes of the Computer Revolution

Hackers: Heroes of the Computer Revolution

Hackers: Heroes of the Computer Revolution is a book by Steven Levy about hacker culture. It was published in 1984 in Garden City, New York by Anchor Press/Doubleday...

, a book by Steven Levy

Steven Levy

Steven Levy is an American journalist who has written several books on computers, technology, cryptography, the Internet, cybersecurity, and privacy.-Career:...

 in which Greenblatt appears. The number VI refers to the PDP-6

PDP-6

The PDP-6 was a computer model developed by Digital Equipment Corporation in 1963. It was influential primarily as the prototype for the later PDP-10; the instruction sets of the two machines are almost identical.The PDP-6 was DEC's first "big" machine...

 machine for which it was written.

Development

Greenblatt was inspired to write Mac Hack upon reading MIT Artificial Intelligence Memo 41, or a similar document describing Kotok-McCarthy

Kotok-McCarthy

Kotok-McCarthy also known as was the first computer program to play chess convincingly. It is also remembered because it played in and lost the first chess match between two computer programs.-Development:...

, which he saw while visiting Stanford University

Stanford University

The Leland Stanford Junior University, commonly referred to as Stanford University or Stanford, is a private research university on an campus located near Palo Alto, California. It is situated in the northwestern Santa Clara Valley on the San Francisco Peninsula, approximately northwest of San...

 in 1965. A good chess player, he was inspired to make improvements at MIT in 1965 and 1966.

In about 2004, he had an opportunity to tell Alan Kotok

Alan Kotok

Alan Kotok was an American computer scientist known for his work at Digital Equipment Corporation and at the World Wide Web Consortium...

 that "7 7" would have done better than "4 3 2 2 1 1 1 1 0 0" in Kotok-McCarthy's REPLYS subroutine which generated each player's next plausible moves.

Greenblatt added fifty heuristic

Heuristic

Heuristic refers to experience-based techniques for problem solving, learning, and discovery. Heuristic methods are used to speed up the process of finding a satisfactory solution, where an exhaustive search is impractical...

s that reflected his knowledge of chess. Mac Hack was written in MIDAS macro assembly language

Assembly language

An assembly language is a low-level programming language for computers, microprocessors, microcontrollers, and other programmable devices. It implements a symbolic representation of the machine codes and other constants needed to program a given CPU architecture...

 on the PDP-6

PDP-6

The PDP-6 was a computer model developed by Digital Equipment Corporation in 1963. It was influential primarily as the prototype for the later PDP-10; the instruction sets of the two machines are almost identical.The PDP-6 was DEC's first "big" machine...

 computer DEC

Digital Equipment Corporation

Digital Equipment Corporation was a major American company in the computer industry and a leading vendor of computer systems, software and peripherals from the 1960s to the 1990s...

 donated to MIT (the first working PDP-6, serial number 2). Many versions may exist. During this period the program was compiled

Compiler

A compiler is a computer program that transforms source code written in a programming language into another computer language...

 about two hundred times.

Tournament play

By the time it was published in 1969 Mac Hack had played in eighteen tournaments and hundreds of complete games. The PDP-6 became an honorary member of the Massachusetts State Chess Association and the United States Chess Federation

United States Chess Federation

The United States Chess Federation is a non-profit organization, the governing chess organization within the United States, and one of the federations of the FIDE. The USCF was founded in 1939 from the merger of two regional chess organizations, and grew gradually until 1972, when membership...

, a requirement for playing tournaments. In 1966 the program was rated 1243 when it lost in the Massachusetts

Massachusetts

The Commonwealth of Massachusetts is a state in the New England region of the northeastern United States of America. It is bordered by Rhode Island and Connecticut to the south, New York to the west, and Vermont and New Hampshire to the north; at its east lies the Atlantic Ocean. As of the 2010...

 Amateur Championship. In 1967, the program played in four tournaments, winning three games, losing twelve, and drawing

Draw (chess)

In chess, a draw is when a game ends in a tie. It is one of the possible outcomes of a game, along with a win for White and a win for Black . Usually, in tournaments a draw is worth a half point to each player, while a win is worth one point to the victor and none to the loser.For the most part,...

 three. In 1967 Mac Hack VI defeated a person with a USCF rating

Elo rating system

The Elo rating system is a method for calculating the relative skill levels of players in two-player games such as chess. It is named after its creator Arpad Elo, a Hungarian-born American physics professor....

 of 1510 in game 3, tournament 2 of the Massachusetts State Championship.

Greenblatt published the program with Donald E. Eastlake III and Stephen D. Crocker in MIT Artificial Intelligence Memo 174 and recorded some games there.

Influence

Mac Hack played by teletype

Teleprinter

A teleprinter is a electromechanical typewriter that can be used to communicate typed messages from point to point and point to multipoint over a variety of communication channels that range from a simple electrical connection, such as a pair of wires, to the use of radio and microwave as the...

, was ported to the PDP-10

PDP-10

The PDP-10 was a mainframe computer family manufactured by Digital Equipment Corporation from the late 1960s on; the name stands for "Programmed Data Processor model 10". The first model was delivered in 1966...

 and was the first computer chess program to be widely distributed. Greenblatt and Tom Knight went on to advance artificial intelligence

Artificial intelligence

Artificial intelligence is the intelligence of machines and the branch of computer science that aims to create it. AI textbooks define the field as "the study and design of intelligent agents" where an intelligent agent is a system that perceives its environment and takes actions that maximize its...

 and build the Lisp machine

Lisp machine

Lisp machines were general-purpose computers designed to efficiently run Lisp as their main software language. In a sense, they were the first commercial single-user workstations...

in 1973.