This is a list of bidding systems used in contract bridge.[1][2] Systems listed have either had an historical impact on the development of bidding in the game or have been or are currently being used at the national or international levels of competition.
Bidding systems are characterized as belonging to one of two broadly defined categories:
natural bidding systems and
artificial bidding systems.
Nevertheless, each contains elements of the other given the number and variety of treatments and conventions that have been developed by bridge bidding theorists.
