Contract bridge, usually known simply as bridge, is a trick-taking card game using astandard deck of 52 playing cards played by four players in two competing partnerships[1]sitting opposite each other around a table.[2] For purposes of scoring and reference, each player is identified by one of the points of the compass and thus North and South play against East and West.[3] The game consists of several hands (or deals) each progressing through four phases: dealing the cards, the auction (also referred to as bidding), playing the hand, and scoring the results.[4] Dealing the cards and scoring the results are procedural activities while the auction and playing the hand are the two actively competitive phases of the game.


Cards are dealt clockwise, one at a time and face down starting on the dealer\'s[5] left so that each player receives thirteen cards. The auction starts with the dealer and rotates around the table clockwise with each player making a call,[6] the purpose being to determine which partnership will contract to take more tricks given a particular trump suit or notrump (known as the strain).[7] The partnership who makes the highest bid is said to have won the bidding and is referred to as the declaring side. The player on the declaring side who, during the auction, first stated the strain ultimately becoming trumps or notrumps is referred to as thedeclarer. The rules of play are similar to other trick-taking games with the additional feature that the hand of declarer\'s partner is displayed face up on the table after the opening leadhas been made by the member of the defending partnership to the left of declarer; the displayed hand is referred to as the dummy and is played by declarer. After all thirteen tricks have been played, the hand\'s score is determined by comparing the actual number of tricks taken by the declaring partnership with that proposed in the contract and awarding points accordingly. Individual scores of several hands are accumulated to determine the overall game score.


While the game involves skill and chance, it has many variants and event types designed to emphasize skill, vary the method of scoring, set limits on the nature of the bidding systemswhich may be used, limit the duration of play, have larger team composition, provide country representation in international play, and to group players of similar interests, skill levels, age, or gender, or combinations thereof. The most common game variants are rubber bridge andduplicate bridge. In rubber bridge, two partnerships participate in the game at one table and the objective is to score the most number of points in the play of several hands. In duplicate bridge, there are more tables and partnerships and the hands are dealt and played in such a manner that each partnership plays the same set of hands and with the scoring based upon relative performance.


Competitions in duplicate bridge range from small clubs with a handful of tables, to large tournaments such as theWorld Bridge Championships[8] where hundreds of tables play the same hands. The game variant and associated method of scoring has significant influence on bidding and card play strategies.