Duplicate Bridge is the most widely used variation of contract bridge in club and tournament settings.
It is called duplicate because the same bridge hand (i.e. arrangement of cards) is duplicated at other tables, in order to allow a fair comparison of playing skill and reduce "luck of the cards". In this way, every hand, whether good or bad, is played in competition with others playing the identical cards, and the element of skill is heightened whilst that of chance is reduced. Duplicate bridge stands in contrast to rubber bridge where each hand is freshly dealt and scores depend as much on the cards as on the players.
Bridge boards, simple four-way card holders, are used to enable each player's hand to be passed intact to the next table that must play the deal, and final scores are calculated by comparing each pair's result with others who played the same hand. Bidding boxes are often used to facilitate the mechanics of bidding, prevent inadvertent passing of information, and minimize the noise level. Screens are used in higher levels of competition and were introduced to eliminate cheating.
In duplicate bridge, a player normally plays with the same partner throughout an event. The two are known as a "pair". There are two exceptions: on team events with up to five or six members swapping partners for portions of the event, and in individual tournaments, in which players change partners for each round.