The first chess effort on the part of a computer is a mate in 2 programmed in 1949 on a Ferranti digital machine.
The first computer program that played proper chess was written at MIT by Alex Bernstein in 1959.
The Massachusetts Amateur Championship marked the first time a chess computer played chess against human beings under tournament conditions in 1967. MacHack VI, from MIT, ended up with a 1239 provisional rating.
The first chess tournament in which the only players were computer programs was held in New York in 1970. There were 6 computer programs competing. The event was won by a CDC 6400 computer (CHESS 3.0) located at Northwestern University in Evanston, Illinois.
The first world computer championship was held in Stockholm in 1974 and won by the Soviet program, KAISSA.
Cray Blitz was the first chess computer to win a US state chess championship when it won the Mississippi Championship in 1981.
1983 was the first time a microcomputer beat a master in tournament play.
1983 was the first time a computer gained an established master's rating.
In May, 1997 DEEP BLUE defeated world champion Garry Kasparov in a match.
In 2005, HYDRA defeated Michael Adams, #7 in the world, with 5 wins and 1 draw.
In 2006, DEEP JUNIOR won the 14th World Computer Chess Championship.