Blitz chess (more commonly known as speed chess) simply refers to a game of chess that has a fast time control.

Time controls for each player in a game of blitz chess are, according to FIDE (French - Fédération Internationale des Échecs, English - International Chess Federation), 10 minutes or less per player. This can be played with or without an increment or delay per move—a more recent development due to the influx of digital clocks. Three minutes with a two-second increment is preferred. In the case of time increments, the total time per player for a 60-move game must be 10 minutes or less (hence averaging 10 seconds or less per move).

Before the advent of digital clocks, five minutes per side was the standard for blitz or speed chess. Before the introduction of chess clocks in the mid-1950s, chess club "rapid transit" tournaments had a referee who every ten seconds called out.

In 1988, Walter Browne formed the World Blitz Chess Association and its magazine "Blitz Chess", which folded in 2003.

More Info: en.wikipedia.org