Before there were Thoresen Chess Engine Competitions (TCECs) to determine the world’s strongest chess computer, there were the ACM tournaments.

The Association for Computing Machinery (ACM) hosted the first major chess tournament for computers, the First United States Computer Chess Championship, in August-September, 1970 at the New York Hilton. The event was organized by Dr. Monroe (Monty) Newborn (1938- ), who was then Professor of Computer Science at Columbia University. It was won by CHESS 3.0, a chess program from Northwestern University, written by David Slate, Larry Atkin, and Keith Gorlen. Six programs competed that year. Chess programs were played on an IBM 360/91, two IBM 360/65s, a CDC 6400 (the computer used by CHESS 3.0), a Burroughs B5500, and a Varian 620/i. The programs were CHESS 3.0 (scored 3-0), DALY CP (2-1), COKO 3 (1.5-1.5), J BIIT (1.5-1.5), SCHACH (1-2), and WITA (0-3). CHESS 3.0 was written in Fortran IV and COMPASS. Daly CP (chess program) was written in IDIIOM assembly language by NASA researcher Chris Daly and Ken King using only 4K of memory. COKO was written in Fortran IV by Dennis Cooper and Ed Kozdrowicki. J. BIIT was written in PL/I by Hans Berliner. SCHACH was written in Fortran IV by Dan Drew, Rolf Smith, and Franklin Ceruti. WITA was written in Algol by Tony Marsland. The time control was 40 moves in 2 hours, and 10 moves every subsequent hour. The rules also included time-out provisions in the case of system failures or communication failures. These time-outs were frequently used in 1970. Jaques Dutka, a mathematician and former chess master, was the tournament director. The Daly CP IDIIOM workstation was the only computer on site. The other programs had long distance communication links to their mainframe computers. Daly CP was one of the first chess programs with a Graphical User Interface (GUI).

In August 1971, CHESS 3.5 (an improved version of CHESS 3.0) won the 2nd Annual ACM North American Computer Chess Championship NACCC), held at the Chicago Hilton. CHESS 3.5, programmed by Larry Atkin and David Slate, won all its games. Other programs were TECH (2-1), GENIE (2-1), DAVID (1.5-1.5), CCCP (1.5-1.5), COKO 3 (1-2), SCHACH (1-2), and MR. TURK (0-3). Professor Ben Mittman from Northwestern University organized the event. International Master David Levy from Scotland was the tournament director. TECH was written in BLISS, a system programming language developed at Carnegie Mellon University. GENIE was a program that ran under a time sharing system using a teletype for man-machine communication. In the game COKO vs. GENIE, the COKO program missed a mate in one and various mates in two. COKO had not been programmed how to choose between alternate mates, so it didn’t, and lost.

In August 1972, CHESS 3.6 won the 3rd ACM NACCC tournament at the Sheraton Hotel in Boston. Chess 3.6 won all 3 of its games. Other programs were TECH (2-1), COKO 3 (2-1), OSTRICH (2-1), SCHACH (1-2), USC CP (1-2), MSU CP (0.5-2.5), and LEVERETT CP (0.5-2.5). Once again, David Levy was the tournament director. OSTRICH was written in Assembly by Monty Newborn and Columbia University student George Arnold.

In August 1973, CHESS 4.0 won the 4th ACM NACCC tournament at the Hyatt Regency in Atlanta with the score of 3.5-0.5. Other programs were CHAOS (3-1), OSTRICH (3-1), TECH 2 (3-1), DARTMOUTH CP (2-2), TECH (2-2), T. BELLE (2-2), COKO 4 (1.5-2.5), GEORGIA TECH CP (1.5-2.5), THE FOX (1-3), USC CP (1-3), and CHES (0.5-3.5). After the tournament, International Master Charles Kalme played Chaos and Chess 4.0 with queen odds. He won against Chaos, but lost against Chess 4.0. David Levy was the tournament director. T. Belle was written by Ken Thompson. It was a conventional brute force program written for a general-purpose minicomputer.

In 1974, RIBBIT of the University of Waterloo won the 5th ACM tournament in San Diego. The other programs were CHESS 4.0, CHAOS, BELLE, DUCHESS (Duke University), DART 4.1, TECH 2, OSTRICH, CHUTE 1, KCHES6, TYRO, and XENARBOR.

In 1975, CHESS 4.4 (CDC CYBER 175) won the 6th ACM tournament in Minneapolis. Other programs included TREEFROG, ETAOIN SHRDIU, CHAOS, DUCHESS, CHUTE 1.2, TYRO, OSTRICH, WITA, IRON FISH, BLACK KNIGHT, and SORTIE. During this event, International Master David Levy, the tournament director, won a simultaneous exhibition against the 12 computers (10 wins and 2 draws) and won. In 1975, the programs reached the level of class A players (1800-2000 rating). In 1975, the ACM events were renamed the ACM North American Computer Chess Championship (NACCC).

In 1976, CHESS 4.5 won the 7th ACM tournament in Houston. The other programs were CHAOS, BLACK KNIGHT, BLITZ 4, DUCHESS, WITA, CHUTE 1.2, L’EXCENTRIQUE, ETAOIN SHRDIU, CHESSTAR, and XENARBOR 4.

In 1977, CHESS 4.6 won the 8th ACM tournament in Seattle. There were 12 programs entered. The other programs were DUCHESS, CHAOS, XENARBOR, BLITZ 5, BLACK KNIGHT, OSTRICH, CHUTE 1.2, 8080 CHESS, TYRO, WITA, and BRUTE FORCE.

In 1978, BELLE, developed at Bell Laboratories by Ken Thompson, won the 9th ACM tournament in Washington, D.C., after defeating BLITZ 6.5 in the final round. BELLE was the first chess computer with hardware designed specifically for chess. The other programs were CHESS 4.7, CHAOS, BLITZ 6.5, SARGON 2, DUCHESS, OSTRICH 4, MIKE, BLACK KNIGHT, BS6676, AWIT, and BRUTE FORCE.

In 1979, CHESS 4.9 won the 10th ACM tournament in Detroit. In 1979, the programs were expert strength. The other programs were BELLE, DUCHESS, MYCHESS, L’EXCENTRIQUE, CHAOS, SARGON 3, OSTRICH 80, BLITZ 6.9, AWIT, BS6676, and RUFUS.

In 1980, BELLE won the 11th ACM tournament in Nashville. 1980 was the first year that CRAY BLITZ participated in the ACM chess tournaments. The other programs were CHAOS, CHALLENGER 10, BEBE, MYCHESS, OSTRICH 81, CUBE 2.0, AWIT, and CLASH.

In 1981, BELLE won the 12th ACM tournament in Los Angeles. The other programs were NUCHESS, CRAY BLITZ, BEBE, DUCHESS, PHILIDOR, OSTRICH, CHALLENGER, L’EXCENTRIQUE, MYCHESS, CUBE 2.1, CHAOS, SCHACH 2.5, CHATURANGA, AWIT, and PRODIGY.

In 1982, BELLE won the 13th ACM tournament in Dallas in tie-breaks over CRAY BLITZ, NUCHESS, and CHAOS. The other programs were BEBE, ADVANCE 2.4, SAVANT X, FIDELITY 10, OSTRICH, SCHACH 2.6, SFINKS X, PHILIDOR, PION, and CHATURANGA 2.0.

In 1983, CRAY BLITZ won the 14th ACM NACCC tournament in New York. This was also the 4th World Computer Chess Championships, so CRAY BLITZ also became the world computer chess champion. In 1983, the programs were master strength. In October, 1983, BELLE was rated 2203, the first program to be rated master strength.

In 1984, CRAY BLITZ won the 15th ACM tournament in San Francisco. The other programs were BEBE, FIDELITY, CHAOS, BELLE, NUCHESS, PHOENIX, NOVAG, INTELLIGENT, SCHACH 2.7, OSTRICH, AWIT, MERLIN, and XENARBOR.

In 1985, HITECH, developed by Hans Berliner at Carnegie-Mellon, won the 16th ACM tournament in Denver. HITECH became the first computer rated over 2400. The other programs were BEBE, INTELLIGENT, PHOENIX, CRAY BLITZ, CHAOS, LACHEX, SPOCK, OSTRICH, and AWIT.

In 1986, BELLE won the 17th ACM tournament in Dallas. The other programs were LACHEX, NOVAG, BEBE, PHOENIX, MEPHISTO, CHALLENGER, RECOM, CYRUS, FIDELITY, CHIPTEST, MERLIN, VAXCHESS, OSTRICH, WAYCOOL, and REX.

In 1987, CHIPTEST-M, developed by Feng Hsu, won the 18th ACM tournament in Dallas. CHIPTEST caused hash tables to be standard for chess programs. The other programs were CRAY BLITZ, SUN PHOENIX, LACHEX, CRYUS 68K, BEBE, NOVAG, BELLE, WAYCOOL, GNU CHESS, BP, OSTRICH, and GRECO.

In 1988, DEEP THOUGHT 0.02 won the 19th ACM tournament in Orlando. DEEP THOUGHT was rated 2550 in November, 1988. It was the first computer to beat a Grandmaster (Bent Larson), in a tournament game under time control. The other programs were CHALLENGER, MEPHISTO, CRAY BLITZ, HITECH, SUN PHOENIX, BEBE, NOVAG, BP, CRYUS 68K, AI CHESS, and WAYCOOL.

In 1989, HITECH and DEEP THOUGHT tied for first place with 4 points in the 20th ACM tournament held in Reno. MEPHISTO X (best small computing system) and BEBE tied for 3rd place. The other programs were REBEL, CRAY BLITZ, PHOENIX, BP, NOVAG, and ZARKOV. In 1989, the programs were Grandmaster strength.

Up until 1990, games were played with a time control of 40 moves in two hours, then 20 moves an hour after that. Games lasted as long as eight hours. In 1990, each side was given two hours to make all its moves. In 1990 an Endgame Championship was added to the tournament. In 1990, DEEP THOUGHT/88 (rated over 2500) took 1st place in the 21st ACM tournament. DEEP THOUGHT beat David Levy 4-0 in a match. The other programs were MEPHISTO, HITECH, M-CHESS, ZARKOV, BEBE, BELLE, NIGHTMARE, and NOW.

In 1991, DEEP THOUGHT II won the 22nd ACM tournament in Albuquerque. The other programs were M-CHESS, CRAY BLITZ, MEPHISTO, HITECH, CHESSMACH, ZARKOV, SOCRATES, BP, LACHEX, BEBE, and DELICATE BRUTE. In 1991, the event was renamed the ACM International Computer Chess Championship.

In 1993, SOCRATES II, a program that ran on an IBM PC, won the 23rd ACM tournament in Indianapolis. The other programs were CRAY BLITZ, *TECH, B*HITECH, ZARKOV, CHESSMACH, KALLISTO, BP, NOW, MCHESS, BEBE, and INNOVATION.

In 1994, the last ACM chess tournament was held in Cape May, New Jersey. The 24th ACM tournament was won by DEEP THOUGHT II. The other programs were ZARKOV, STAR SOCRATES, NOW, MCHESS PRO, CRAY BLITZ, WCHESS, EVALATOR, INNOVATION II, and SPECTOR.

The ACM chess events were cancelled in 1995 as DEEP BLUE was preparing for the first match against world chess champion Garry Kasparov.

As far as the TCEC tournaments are concerned, in 2008, the winner was Houdini. In February 2011, the winner was Houdini 1.5a over Rybka 4.0. In April 2011, the winner was Houdini 1.5a over Rybka 4.1. In May 2013, the winner was Houdini 3 over Stockfish 250413. In December 2013, the winner was Komodo 1142 over Stockfish 191113. In May 2014, the winner was Stockfish 170514 over Komodo 7x. In July 2014, the winner was Stockfish 260614 over Houdini 4. In December 2014, the Grand Champion was Komodo 1333 over Stockfish 141214. TCEC is regarded as the Unofficial World Computer Chess Championship because it uses the strongest chess engines with long time control (120 minutes + 30 seconds added per move for the whole game) matches on high-end hardware.

Also see The Slate/Atkin program and CHESS x.x at http://www.chess.com/blog/billwall/the-slateatkin-program-and-chess-xx
Computer chess history – http://www.chess.com/article/view/computers-and-chess—a-history

Bill Wall