This stands in contrast to Bridge played without duplication, where each hand is freshly dealt and where scores may be more affected by chance in the short run.

Four-way card holders known as bridge boards are used to enable each player's hand to be preserved from table to table, and final scores are calculated by comparing each pair's result with others who played the same hand.

In duplicate bridge, players normally play all the hands with the same partner, and compete either as a partnership (in a 'Pairs tournament') or on a team with one or more other partnerships ('Teams tournament' - players are usually allowed to change partner within their team at any point if they wish).

In the introduction to his book Duplicate Whist, the author comments on the early emergence of duplicate whist: The writer has it on good authority that it was played in Berlin and Paris as far back as 1840, and later in Philadelphia and New York... Mitchell also recounts the Cavendish experiment of 1857 to demonstrate the merits of duplicate whist in reducing the element of luck and to distinguish between the skill levels of better and poorer players.

Cavendish concludes: ...that this experiment does not altogether eliminate luck, as bad play sometimes succeeds.

But by far the greater part of luck, namely, that due to the superiority of winning cards, is by the plan described quite got rid of.Initially, owing to the early clumsy mechanics of card resorting to reconstruct the hands of a just played deal,[1] the problems resulting from errors made in the transferring of cards between tables, and the unaccustomed movement of players between tables and the resultant slower pace of play, duplicate whist did not gain instant popularity.

Nevertheless, the evolution of duplicate whist continued and the procedures and apparatus (known as trays or now, more commonly, boards) for more conveniently maintaining and transferring the cards of each deal for replay had been greatly improved so that by the 1890s duplicate's popularity had become widespread.

In a pairs tournament, each deal is played a number of times by different players, after which all the scores are compared.

The information recorded includes at least the (identifying) numbers of the North-South and East-West pairs and the score achieved.

Usually the contract and the number of tricks won are also recorded, and sometimes also the opening lead.

This might be regarded as an advantage or as a disadvantage: information about their relative standing in the field might induce a pair to change their strategy (e.g. aggressive or conservative bidding and play) on the remaining hands.

Alternatively, the scores for each round may be recorded on pickup slips collected during the event to enable the scorer to start to process the results before the end of the session, so that the results can be announced soon after the end of the session.

A modern development is an electronic data-entry device on each table that transmits the results wirelessly to the director's computer.

[2] This allows results to be posted at a club or on a website very quickly after the end of play.

In this movement, the boards remain stationary while the players move according to guide cards.

This movement has the disadvantage of requiring a larger number of physical tables, and thus more space.

Trials are usually reserved for high-level competitions (such as regional and national championships, invitation tournaments etc.).

One session consists of only one round, with boards circulating among the tables and pairs remaining seated.

Depending on the number of teams competing and the structure of the tournament, a relatively larger number of boards may be played in each round of the movement (usually six to eight for "Swiss teams", usually 12, 24, or more for knockout events).

In rubber (as in IMP scoring), 30 points above the line for an overtrick is unimportant and hardly worth risking a set.

In match-points duplicate, it is common for those 30 points to mean you get a top score instead of average – and may be worth risking going down.

In rubber, an occasional 800-point penalty is disastrous, but in matchpoints it is no worse than any other bottom score.

In duplicate bridge, once a pair recognizes that they are playing for part score (less than a game), their objective is to win the auction with the minimum bid.

In rubber bridge, it may occasionally be desirable to bid above this minimum as points below the line may be needed to complete a game.

Duplicate bridge also has the unique advantage of largely neutralizing a run of bad luck with the cards because a pair that has had poor hands all night may still have the highest score for the session – as long as they play their cards more skillfully than the other pairs with the same poor hands.

That said, in such cases these pairs will probably have had fewer opportunities to exercise those skills, and their results may depend more heavily on the expertise of their opponents.

[12] Players may also be members of clubs that operate some bridge competition sanctioned by the ACBL.

They are primarily designed not as punishment for irregularities but rather for the rectification of situations where nonoffenders may otherwise be damaged.