Explanation
In an ordinary Swiss tournament, the earliest rounds can pair very strong participants against much weaker ones. Accelerated pairing temporarily changes how those early groups are built so players of more similar strength tend to meet sooner.
The idea is not to award real tournament points or alter the final standings. In FIDE's approved Baku method, for example, an upper part of the starting list receives virtual points used only to build pairing scoregroups. Those virtual points are reduced during the accelerated rounds and later disappear; only points actually scored in games count in the tournament standings.
Acceleration is a layer applied to an existing Swiss pairing system, not a completely different tournament format. Its main effect is at the beginning, where it aims to produce competitive games earlier and reduce rounds whose results are highly predictable from large strength differences.
Usage and context
FIDE approves specific acceleration methods, including the Baku method. An improvised change to early pairings is not automatically equivalent to an approved system.
Common confusions
Virtual points versus real points
Virtual points may affect whom a player is paired with, but they do not increase the player's actual tournament score.
