An Internet chess server (ICS) is an external server that provides the facility to play, discuss, and view the board game of chess over the Internet. The term specifically refers to facilities for connecting players through a variety of graphical chess clients located on each user's computer.
In the 1970s, one could play correspondence chess in a PLATO System program called 'chess3'. Several users used chess3 regularly; often a particular user would make several moves per day, sometimes with several games simultaneously in progress. In theory one could use chess3 to play a complete game of chess in one sitting, but chess3 was not usually used this way. PLATO was not connected to Internet predecessor ARPANET in any way that allowed mass use by the public, and consequently, chess3 was and still is relatively unknown to the public.
In the eighties, chess play by email was still fairly novel. Latency with email was less significant than with traditional correspondence chess via paper letters. Often one could complete a dozen moves in a week. As network technology improved, public, widespread use of a centralised server for live play became a possibility.
Michael Moore, of the University of Utah, and Richard Nash recognised the potential of an Internet chess server and created its first incarnation, hosted at lark.utah.edu and accessible through telnet. The official opening date of the ICS was January 15, 1992. John Chanak, William Kish, and Aaron Putnam moved the server to a host machine at Carnegie Mellon University in July 1992, and took over its operation. Although it was buggy and suffered from lag problems, the server was popular among a small group of chess enthusiasts. Over time, many features were added to the ICS, such as Elo ratings and support for graphical clients, and the server was made more stable.
In late 1992, Daniel Sleator, professor of computer science at Carnegie Mellon University, took over management of the ICS. He addressed, among other issues, the frequent complaint that players would lose blitz games on time due to network lag.