GameKnot is an Internet chess server featuring tournaments an league play, along with Java single-player games, without the need to download additional software . GameKnot has been in business since 2001 and currently has approximately 750,000 registered players who have logged over 13 million games and are, as of April 2008, currently playing about 130,000 games. For a typical match, unless two users are simultaneously logged in and committed to playing quickly, games are generally played over a period of days (for example, up to three days per move per person), weeks or even months, and games may resemble a correspondence chess match. The site offers a wide variety of features, including an extensive database including generally recognized names for chess openings, site-sponsored tournaments, player-sponsored mini-tournaments, a fast-paced Blitz chess Java application in its beta stages (it has a known black castling bug), the ability to program conditional moves during a game, the option to declare a vacation to suspend games, and an in-game "analyze board" function that allows players to explore potential moves. It also keeps a record of past games, allowing players to learn from previous wins and losses. GameKnot maintains a ranking system similar to the Elo rating system used by the World Chess Federation.