Editing Contract bridge (section)

== Gameplay ==

=== 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" />

=== Setup and dealing ===
[[File:Bridge table.png|thumb|left|280px|{{center|Partners sit opposite each other.}}]]
The four players sit in two partnerships with players sitting opposite their partners. A [[cardinal direction]] is assigned to each seat, so that one partnership sits in North and South, while the other sits in West and East.{{Sfn|Gibson|1974|p=134}} The cards may be freshly dealt or, in duplicate bridge games, pre-dealt.<ref name="law8">[[#rubberlaws|Laws of Rubber Bridge]], Law 8, pp. 5&ndash;6.</ref><ref name="duplaw6">[[#duplicatelaws|Laws of Duplicate Bridge]], Law 6, pp. 9&ndash;10.</ref> All that is needed in basic games are the cards and a method of keeping score, but there is often other equipment on the table, such as a board containing the cards to be played (in duplicate bridge), [[bidding box]]es, or [[Screen (bridge)|screens]].<ref name="duplaw7">[[#duplicatelaws|Laws of Duplicate Bridge]], Law 7, p. 11.</ref><ref name="biddingbox">[[#duplicatelaws|Laws of Duplicate Bridge]], p. 136: "The ACBL Board of Directors authorizes tournament organizers in ACBL sanctioned events to use bidding boxes."</ref><ref name="duplaw80">[[#duplicatelaws|Laws of Duplicate Bridge]], Law 80, pp. 99&ndash;100.</ref>

[[File:Bridge boards box.jpg|thumb|220px|{{center|[[Board (bridge)|Duplicate Boards]] with cards}}]]
In rubber bridge each player draws a card at the start of the game; the player who draws the highest card deals first. The second highest card becomes the dealer's partner and takes the chair on the opposite side of the table. They play against the other two.<ref name="law3" /> The deck is shuffled and cut, usually by the player to the left of the dealer, before dealing. Players take turns to deal, in clockwise order. The dealer deals the cards clockwise, one card at a time.<ref name="law8" /><ref name="law4">[[#rubberlaws|Laws of Rubber Bridge]], Law 4, p. 4.</ref> Normally, rubber bridge is played with two packs of cards and whilst one pack is being dealt, the dealer's partner shuffles the other pack. After shuffling the pack is placed on the right ready for the next dealer. Before dealing, the next dealer passes the cards to the previous dealer who cuts them.

In duplicate bridge the cards are pre-dealt, either by hand or by a computerized dealing machine, in order to allow for competitive scoring. Once dealt, the cards are placed in a device called a [[Board (bridge)|"board"]], having slots designated for each player's cardinal direction seating position. After a deal has been played, players return their cards to the appropriate slot in the board, ready to be played by the next table.<ref name="duplaw6be">[[#duplicatelaws|Laws of Duplicate Bridge]], Law 6B & 6E, pp. 9&ndash;10.</ref><ref name="duplaw7bc">[[#duplicatelaws|Laws of Duplicate Bridge]], Law 7B & 7C, p. 11.</ref>

=== Auction ===
{| class="wikitable floatright" style="width:220px; border:1px"
|- style="font-size:90%"
| valign="top" halign="center"|
{| class="wikitable" style="margin-left:0px; margin-right:0px; width:218px; border:0.5px"
|-
!West||North||East||South
|- style="text-align:center; font-size:120%;"
|+ {{center|'''Example auction'''}}
|- style="text-align:center; font-size:120%;"
| || ||1{{diamonds}}||1{{Hearts}}
|- style="text-align:center; font-size:120%;"
|1{{Spades}}||2{{clubs}}||2{{Spades}}||3{{Clubs}}
|- style="text-align:center; font-size:120%;"
|4{{spades}}||Pass||4NT||Pass
|- style="text-align:center; font-size:120%;"
|5{{diamonds}}||Pass||6{{spades}}||Pass
|- style="text-align:center; font-size:120%;"
|Pass||Pass || ||
|} East-West and North–South compete for the contract. East-West prevail, specifying the trump suit (spades) and the minimum number of tricks beyond six which they must win, six.
|}
The dealer opens the auction and can make the first call, and the auction proceeds clockwise.{{Efn|e.g., if North is the dealer, they make a call, then the auction continues with East, South, West, and so on.}} When it is their turn to call, a player may pass{{snd}}but can enter into the bidding later{{snd}}or bid a contract, specifying the level of their contract and either the trump suit or ''no trump'' (the denomination), provided that it is higher than the last bid by any player, including their partner.{{Sfn|Gibson|1974|p=135}} All bids promise to take a number of tricks in excess of six, so a bid must be between one (seven tricks) and seven (thirteen tricks). A bid is higher than another bid if either the level is greater (e.g., 2{{clubs}} over 1NT) or the denomination is higher at the same level, with the order being in ascending (or alphabetical) order: {{clubs}}, {{diamonds}}, {{hearts}}, {{spades}}, and NT (no trump) (e.g., 3{{spades}} over 3{{diamonds}}).{{Sfn|Gibson|1974|p=135}} Calls may be made orally or with a bidding box.

If the last bid was by the opposing partnership, one may also {{gcb|double}} the opponents' bid, increasing the penalties for undertricks, but also increasing the reward for making the contract. Doubling does not carry to future bids by the opponents unless future bids are doubled again. A player on the opposing partnership being doubled may also {{gcb|redouble}}, which increases the penalties and rewards further.{{Sfn|Gibson|1974|pp=135&ndash;136}} Players may not see their partner's hand during the auction, only their own. There exist many bidding conventions that assign agreed meanings to various calls to assist players in reaching an optimal contract (or obstruct the opponents).<ref name="law40">[[#rubberlaws|Laws of Rubber Bridge]], Law 40, pp. 18&ndash;19.</ref>

The auction ends when, after a player bids, doubles, or redoubles, every other player has passed, in which case the action proceeds to the play; or every player has passed and no bid has been made, in which case the round is considered to be "passed out" and not played.<ref name="law22"/>

=== Play ===
The player from the declaring side who first bid the denomination named in the final contract becomes declarer.{{Efn|For example, if player A bids 2{{hearts}} and player B, their partner, raises to 4{{hearts}} and that becomes the final contract, then player A becomes declarer.}}<ref name="defdeclarer">[[#rubberlaws|Laws of Rubber Bridge]], Part I ("Definitions"): Declarer.</ref> The player left to the declarer leads to the first trick. Dummy then lays his or her cards face-up on the table, organized in columns by suit. Play proceeds clockwise, with each player required to follow suit if possible. Tricks are won by the highest trump, or if there were none played, the highest card of the led suit.{{Sfn|Gibson|1974|pp=136–137}} The player who won the previous trick leads to the next trick. The declarer has control of the dummy's cards and tells his partner which card to play at dummy's turn.<ref name="law43">[[#rubberlaws|Laws of Rubber Bridge]], Law 43, p. 20.</ref> There also exist conventions that communicate further information between defenders about their hands during the play.<ref name="law41"/>

At any time, a player may {{gcb|claim}}, stating that their side will win a specific number of the remaining tricks. The claiming player lays his cards down on the table and explains the order in which he intends to play the remaining cards. The opponents can either accept the claim and the round is scored accordingly, or dispute the claim. If the claim is disputed, play continues with the claiming player's cards face up in rubber games,<ref name="law6871">[[#rubberlaws|Laws of Rubber Bridge]], Law 68–71, pp. 32–34.</ref> or in duplicate games, play ceases and the tournament director is called to adjudicate the hand.<ref name="lawd6871">[[#rubberlaws|Laws of Rubber Bridge]], Law 68–71, pp. 82–86.</ref>

=== Scoring ===
{{main|Bridge scoring}}
At the end of the hand, points are awarded to the declaring side if they make the contract, or else to the defenders. Partnerships can be {{gcb|vulnerable}}, increasing the rewards for making the contract, but also increasing the penalties for undertricks. In rubber bridge, if a side has won 100 contract points, they have won a {{gcb|game}} and are vulnerable for the remaining rounds,{{Sfn|Gibson|1974|p=138}} but in duplicate bridge, vulnerability is predetermined based on the number of each board.<ref name="duplaw2">[[#duplicatelaws|Laws of Duplicate Bridge]], Law 2, p. 6.</ref>

If the declaring side makes their contract, they receive points for {{gcb|odd tricks}}, or tricks bid and made in excess of six. In both rubber and duplicate bridge, the declaring side is awarded 20 points per odd trick for a contract in clubs or diamonds, and 30 points per odd trick for a contract in hearts or spades. For a contract in notrump, the declaring side is awarded 40 points for the first odd trick and 30 points for the remaining odd tricks. Contract points are doubled or quadrupled if the contract is respectively doubled or redoubled.{{Efn|If the declaring side makes a contract of 3NT and takes exactly nine tricks, fulfilling the contract (6&nbsp;+&nbsp;3), they receive 40 points for the first odd trick, and 60 (30&nbsp;×&nbsp;2) points for the remaining odd tricks, adding up to 100 contract points. If the contract was doubled or redoubled, the declaring side receives 200 and 400 points respectively. Additional bonus points may apply depending on the variation played; for example, in duplicate bridge, the declaring side is awarded a game bonus for having won 100 or more contract points, which is 500 if vulnerable, for a total of 600 points (500 + 100), or 300 if not vulnerable, for a total of 400 points (300&nbsp;+&nbsp;100).}}

In rubber bridge, a partnership wins one game once it has accumulated 100 contract points; excess contract points do not carry over to the next game. A partnership that wins two games wins the rubber, receiving a bonus of 500 points if the opponents have won a game, and 700 points if they have not.<ref name="law72to74">[[#rubberlaws|Laws of Rubber Bridge]], Law 72–74, pp. 34&ndash;35.</ref>

Overtricks score the same number of points per odd trick, although their doubled and redoubled values differ.<ref name="law81" /><ref name="duplaw77">[[#duplicatelaws|Laws of Duplicate Bridge]], Law 77, p. 95.</ref> Bonuses vary between the two bridge variations both in score and in type (for example, rubber bridge awards a bonus for holding a certain combination of high cards),<ref name="law81" /> although some are common between the two.

A larger bonus is awarded if the declaring side makes a small slam or grand slam, a contract of 12 or 13 tricks respectively. If the declaring side is not vulnerable, a small slam gets 500 points, and a grand slam 1000 points. If the declaring side is vulnerable, a small slam is 750 points and a grand slam is 1,500.<ref name="law81" /><ref name="duplaw77" />

In rubber bridge, the rubber finishes when a partnership has won two games, but the partnership receiving the most ''overall'' points wins the rubber.<ref name="law72to74" /> Duplicate bridge is scored comparatively, meaning that the score for the hand is compared to other tables playing the same cards and match points are scored according to the comparative results: usually either "matchpoint scoring", where each partnership receives 2 points (or 1 point) for each pair that they beat, and 1 point (or {{1/2}} point) for each tie; or IMPs (international matchpoint) scoring, where the number of IMPs varies (but less than proportionately) with the points difference between the teams.<ref name="duplaw77" />

Undertricks are scored in both variations as follows:<ref name="law81" /><ref name="duplaw77" />
{|class="wikitable"
!rowspan="3"|Undertricks
!colspan="6"|Points per undertrick
|-
!colspan="3"|Vulnerable
!colspan="3"|Not vulnerable
|-
!Undoubled
!&nbsp;Doubled&nbsp;
!Redoubled
!Undoubled
!&nbsp;Doubled&nbsp;
!Redoubled
|-
|1st undertrick
|rowspan="3" align=center|100
|align=center|200
|align=center|400
|rowspan="3" align=center|50
|align=center|100
|align=center|200
|-
|2nd and 3rd, each
|align=center|300
|align=center|600
|align=center|200
|align=center|400
|-
|4th and each subsequent
|align=center|300
|align=center|600
|align=center|300
|align=center|600
|}