Editing Contract bridge (section)

=== Overview ===
Bridge is a four-player partnership [[trick-taking game]] with thirteen tricks per deal.<ref name="law1">[[#rubberlaws|Laws of Rubber Bridge]], Law 1, p. 3.</ref><ref name="law3">[[#rubberlaws|Laws of Rubber Bridge]], Law 3, pp. 3&ndash;4.</ref> The dominant variations of the game are [[rubber bridge]], which is more common in social play; and [[duplicate bridge]], which enables comparative scoring in tournament play. Each player is dealt thirteen cards from a standard 52-card deck. A {{gcb|trick|trick}} starts when a player leads (i.e., plays the first card). The leader to the first trick is determined by the auction; the leader to each subsequent trick is the player who won the preceding trick. Each player, in clockwise order, plays one card on the trick. Players must play a card of the same suit as the original card led, unless they have none (said to be "void"), in which case they may play any card.<ref name="law44" />

[[File:Four overlapping playing cards.jpg|thumb|upright=1.2|In this trick, North led {{spades}}10 so all players must play a spade unless they have none.<ref name="law44">[[#rubberlaws|Laws of Rubber Bridge]], Law 44, pp. 20&ndash;21.</ref> East "follows suit" with {{spades}}K, South with {{diamonds}}J and West with {{hearts}}7. In a no-trump game, East wins the trick, having played the highest spade. If diamonds or hearts are trumps, South or West respectively win.]]

The rank of the cards played determines which player wins the trick. Within each suit, the ace is ranked highest followed by the king, queen and jack and then the ten through to the two. In a deal in which the auction has determined that there is no trump suit, the trick is won by the highest-ranked card of the suit led; cards of suits other than that led cannot win. In a deal with a trump suit, cards of that suit are superior in rank to any of the cards of any other suit. If one or more players plays a trump to a trick when void in the suit led, the highest-ranked trump wins. For example, if the trump suit is spades and a player is void in the suit led and plays a spade card, they win the trick if no other player plays a higher spade. If a card of the trump suit is led, the usual rule for trick-taking applies and the highest-ranked card of that suit wins.<ref name="law44" />

Unlike that of its predecessor, [[whist]], the goal of bridge is not simply to take the most tricks in a deal.{{Sfn|Gibson|1974|pp=632–636}} Instead, the goal is successfully to estimate how many tricks one's partnership can take, and then to meet or exceed that estimate.<ref name="law72a">[[#rubberlaws|Laws of Rubber Bridge]], Law 72(a), pp. 34&ndash;35.</ref> To illustrate this, the simpler partnership trick-taking game of [[Spades (card game)|spades]] has a similar mechanism: the usual trick-taking rules apply with the trump suit being spades, but in the beginning of the game, players ''bid'' or estimate how many tricks they can win, and the number of tricks bid by both players in a partnership are added. If a partnership takes at least that many tricks, they receive points for the round; otherwise, they lose penalty points.

Bridge extends the concept of bidding into an {{gcb|auction}}, in which partnerships compete to win a {{gcb|contract}}, specifying both how many tricks they will need to take in order to receive points and the trump suit (or ''no trump'', meaning that there will be no trump suit). Players take turns to call in a clockwise order: each player in turn either passes, doubles{{snd}}which increases the penalties for not making the contract specified by the opposing partnership's last bid, but also increases the reward for making it<ref name="law19">[[#rubberlaws|Laws of Rubber Bridge]], Law 19, p. 10.</ref>{{snd}}or redoubles, or states a contract that their partnership will adopt, which must be higher than the previous highest bid (if any).<ref name="law18">[[#rubberlaws|Laws of Rubber Bridge]], Law 18, p. 10.</ref> Eventually, the player who bid the highest contract{{snd}}which is determined by the contract's level as well as the trump suit or no trump{{snd}}wins the contract for their partnership.

In the example auction below, the east–west pair secures the contract of 6{{spades}}; the auction concludes when there have been three successive passes.<ref name="law22">[[#rubberlaws|Laws of Rubber Bridge]], Law 22, p. 11.</ref> Note that six tricks are added to stated contract values, so the six-level contract is a contract of twelve tricks.{{Sfn|Gibson|1974|p=135}}<ref name="law81">[[#rubberlaws|Laws of Rubber Bridge]], Law 81, pp. 37&ndash;39.</ref> In practice, estimating a good contract without information about one's partner's hand is difficult, so there exist many [[bidding system]]s assigning meanings to bids, with common ones including [[Standard American]], [[Acol]], and [[2/1 game forcing]]. Contrast with Spades, where players only have to bid their own hand.

After the contract is decided and the first lead is made, the declarer's partner (dummy) lays their cards face up on the table, and the declarer plays the dummy's cards as well as their own.<ref name="law41">[[#rubberlaws|Laws of Rubber Bridge]], Law 41, p. 19.</ref> The opposing partnership is called the {{gcb|defenders}}, and their goal is to stop the declarer from fulfilling his contract. Once all the cards have been played, the deal is scored: if the declaring side makes their contract, they receive points based on the level of the contract, with some trump suits being worth more points than others and ''no trump'' being worth even more, as well as bonus points for any {{gcb|overtrick|overtricks}}. If the declarer fails to fulfill the contract, the defenders receive points depending on the declaring side's undertricks (the number of tricks short of the contract) and whether the contract was ''doubled'' or ''redoubled''.<ref name="law81" />