Contract bridge

Contract bridge

Bridge declarer play
Alternative names	Bridge
Type	Trick-taking
Players	4
Skills required	Memory, tactics, probability, communication
Cards	52
Deck	French
Play	Clockwise
Card rank (highest to lowest)	A K Q J 10 9 8 7 6 5 4 3 2
Playing time	WBF tournament games = 7.5 minutes per deal
Random chance	Low to moderate (depending on variant played)
Related games
Whist, Auction bridge, Duplicate bridge

See also: Glossary of contract bridge terms

Contract bridge, or simply bridge, is a trick-taking game using a standard 52-card deck. It is played by four players in two competing partnerships, with partners sitting opposite each other around a table. Millions of people play bridge worldwide in clubs, tournaments, online and with friends at home, making it one of the world's most popular card games, particularly among seniors. The World Bridge Federation is the governing body for international competitive bridge.

The game consists of several deals each progressing through four phases: dealing the cards, the auction (also referred to as bidding), playing the cards, and scoring the results. However, most club and tournament play involves some variant of duplicate bridge, where the cards are not re-dealt on each occasion, the same deal being played by two or more different sets of players to enable comparative scoring.

Gameplay

Fundamentals and preliminaries

Scope

Contract bridge has immense scope by virtue of the large number of unique deals which are possible. The 52-card deck can be distributed to the four players some 5.36×10²⁸ ways. In turn, each deal presents many options on how it might be bid and played.

Players

In its most basic form, bridge is a game played by four people in two teams of competing partnerships. For purposes of scoring and reference, each player is identified by one of the cardinal directions and thus North and South play against East and West. More can participate, either as individuals or pairs or as teams of up to six, in formal tournaments or social gatherings where the governing rules of the event are prescribed by the sponsoring host.

Additional designations for each of the four players may be used when referring to their actions during the auction or play of the cards:

• Dealer: the player entitled to make the first call; so chosen by a draw of the cards or in duplicate bridge, so designated by the board to be played
• Opener: the first to make a bid
• Responder: partner of opener
• Intervenor: the first of the opponents to make a call other than pass
• Overcaller: the first of the opponents to make a call other than pass or double
• Advancer: partner of intervenor; also, partner of overcaller
• Declarer: the player who first bids the suit (or notrump) of the ultimate contract
• Dummy: partner of declarer
• First seat: the dealer
• Second seat: the player next in clockwise rotation after the dealer
• Third seat: the player next in clockwise rotation after the player in second seat
• Fourth seat: the player next in clockwise rotation after the player in third seat
• Balancing seat or passout seat: the player who if he passes would end the auction
• Opening leader: the player to the left of declarer; he makes the lead to the first trick
• Left hand opponent (LHO): the player to one's left
• Right hand opponent (RHO): the player to one's right

Contracts and objectives

Contract bridge is a trick-taking card game where on each of several deals the opposing sides first compete in a bidding auction for the right to establish the contract for that deal, the side winning the auction being known as the declaring side. The contract is an exchange of the right to establish which suit, if any, is trumps for an undertaking to win (at least) the number of tricks specified by the highest bid. After the contract has been established, the play of the cards proceeds as in most trick-taking card game until all thirteen tricks have been played; at any time during the play, one side may claim a stated number of the remaining tricks and concede the balance, if any.

Based on the actual number of tricks taken, the declaring side will have either succeeded or failed in fulfilling the contract; if successful (known as making or to have made), the declaring side scores points; if unsuccessful (known as going down or being defeated), the defending side scores points. The overriding objective is to win the contest by accumulating more points than the opponents. Although each variant of bridge has its own particular scheme for awarding and accumulating points, all are based upon whether or not the contract for each deal was made or defeated and by how many tricks.

It can sometimes be advantageous to bid a contract one does not expect to make and to be defeated, thus losing some points, rather than allow the opposing side to bid and make a contract which would score them an even greater number of points. This is known as a sacrifice, and is not uncommon if both sides are contesting the final contract.

Card, suit and bid rankings

In the standard 52-card deck used in bridge, the ace is ranked highest followed by the king, queen, and jack and the spot-cards from the ten down through to the two. Suit denominations also have a rank order with notrump being highest followed by spades, hearts, diamonds and clubs. The two lower-ranked suits (diamonds and clubs) are called the minor suits and the higher-ranked suits (spades and hearts) are called the major suits.

Bidding is based on the premise that the lowest contract available to bidders starts with the proposition to take seven tricks, i.e. one cannot contract to make less than seven tricks. Given this, the bidding is said to start at the one-level when contracting for a total of seven tricks, at the two-level for eight tricks and so on to the seven-level to contract to take all thirteen tricks. The six tricks required as the base for any bid are referred to as the “book”.

Within any level of bidding (i.e. from one to seven), suit rank establishes the bid’s rank, i.e. a bid of two diamonds outranks a bid of two clubs, a bid of three spades outranks a bid of three hearts, a bid of three notrump outranks a bid of three spades. Thus, there are 35 possible basic contracts (five at each of the seven levels); 1♣ being the lowest, followed by 1♦ etc., up to 7NT, the highest possible bid.

Vulnerability

A key feature of bridge is the concept of vulnerability. On each deal, each side is said to be either vulnerable or not vulnerable depending upon whether or not it has won a game in the current rubber; if it has, the side is said to be vulnerable; if it has not, it is said to be not vulnerable. (In duplicate play, the sides' vulnerabilities are pre-defined, depending only on the number of the board.) The scoring points that are won on a deal as a result of making a contract, and the points which are lost when failing to make a contract, are both significantly increased for the side (partnership) that is vulnerable. Accordingly, whether one's side is vulnerable affects one’s strategy for both bidding and play.

Variations

The most common contract bridge variations are rubber bridge and duplicate bridge. Variants within these two types of contract bridge are numerous.

See also: Rubber bridge

In rubber bridge, two partnerships participate in the game at one table and the objective is to score the most points in the play of several hands. A rubber is a 'best-of-three' contest and is completed when one side is first to have won two games. The side which has accumulated the most points and wins the rubber may or may not be the side to have won two games. While rubber bridge is played competitively and for stakes, it is most often played socially and with less formality than duplicate bridge.

See also: Duplicate bridge

In duplicate bridge, the cards held by each player in each deal are preserved so that each partnership plays the same set of hands as their East-West or North-South counterparts at other tables and with the scoring based upon relative performance, thus emphasizing skill over chance. While duplicate is the primary form of higher levels of competitive bridge, it is also played socially.

Dealing

In rubber bridge, partnerships may be self-determined or decided by a cut of the cards, the two highest cut playing against the two lowest, and the first dealer is the player cutting the highest card. The cards are shuffled before each deal, and the dealer deals the cards clockwise one at a time, starting with the left-hand opponent, so that each player receives a hand of thirteen cards. The deal rotates clockwise each hand. In order to save time, a second deck, preferably distinct from the first, is employed so that as the first is being dealt, the second is being shuffled by the partner of the current dealer. When shuffled, the second deck is placed to the shuffler's right, i.e. to the next dealer's left. After the play and scoring of the hand has concluded, the deal is rotated and the second deck is moved by the next dealer from his left to his right, cut by the previous dealer and dealt; the partner of the new dealer shuffles the first deck continuing the process. If the auction is passed out, i.e. no bids are made and only four passes are called, the hands are abandoned and the turn to deal passes in rotation.

Rectangular aluminum board

In duplicate bridge, the hands are shuffled and dealt only once, at the beginning of the session. Players do not play their cards to the centre of the table during the play but instead play them immediately in front of themselves and turn them face down at the end of each trick. The direction that each face down card is pointed indicates which side won each trick, so that at the end of the hand, the number of tricks taken by each side can be determined. At the end of the hand each player returns his hand, intact, to the correct slot in a bridge board such as that shown at right in which it is transported to other tables so that everyone can play the same deals. The results for different players playing the same deal are then compared. This removes much of the element of chance from scores. It also means that in the case of an irregularity or dispute over a hand before the cards are returned to the board, they can be reviewed and it can be determined who played which cards in what order.

In some competitions, boards are pre-dealt prior to the competition, especially if the same hands are to be played at many locations (for example in a large national or international tournament). Mechanical dealing machines may be used for pre-dealing hands at large tournaments and in many clubs. Even for boards dealt or assembled manually, computer software is often used to randomly generate the hands. Before the widespread availability of computers, printed books of random deals could be purchased. In the past it was common for uninteresting hands to be eliminated or replaced, but this practice is now prohibited in sanctioned tournament play. As the boards arrive for play at each subsequent table, the four players take their cards from the board and should count them to ensure that there are 13 cards in their hand before looking at the cards, so that any irregularity can be corrected before the auction and play commence.

In some countries, the rules require that after the hand is played for the first time, the players write the hands down on the traveling scoresheet, which can be consulted later if the cards are accidentally mixed up. Alternatively, if the boards are pre-dealt, "curtain cards" may be supplied which have each hand printed on them, so that each player can check at the beginning of the deal that he has the right cards. Pre-dealt hands also have the advantage that, at the end of the session, diagrams of each deal can be made available to the players for later analysis.

Auction or bidding

See also: Hand evaluation, Bidding system, and Bridge conventions

The auction is a bidding process undertaken within strict procedural and ethical protocols to determine the declaring side and the final contract. The contract is an undertaking to win at least the specified number of odd tricks in the declared denomination. Each partnership works jointly by means of various 'calls' to secure a contract at the highest level deemed advisable by them given their card holdings. A call is limited to a vocabulary of 38 words or phrases consisting of:

• a Bid which states a level and a denomination; given 7 levels of bidding and 5 denominations, there are 35 possible bids
• Double, when the previous call other than pass was a bid by an opponent
• Redouble, when the previous call other than pass was a double by an opponent
• Pass, when unwilling or unable to make one of the three preceding calls

In social games, the players may make their calls orally; otherwise, players use a bidding box containing cards for each possible call and place the respective card face up on the table in front of their position.

The auction starts with the dealer and proceeds clockwise with each player, having first evaluated their hand, making a call in order. During the auction, each bid must be 'sufficient', i.e. it must be higher than its predecessor. A bid is sufficient if it specifies any denomination at a higher level than the last bid, or a higher-ranked denomination at the same level. Thus, after a bid of 3♥, bids of 2♠ or 3♣ are not sufficient, but 3♠ or 4♦ are.

The auction continues until there are three consecutive passes not including the dealer's first call. The partnership which makes the last bid then becomes the "declaring side" and is said to have 'won' the auction. The player on the declaring side who, during the auction, first stated the denomination of the final bid becomes "declarer," the declarer's partner becomes the "dummy," and the opposing side become the "defenders." The defender to the left of declarer must make the opening lead.

In addition to establishing the level and denomination of the final contract, the final contract may be doubled (by the opponents) or redoubled (by the declaring side after the opponents had already doubled), in which case the score for the hand is increased, whether the contract is made or defeated.

If all four players pass in the first round, the deal is not played; in rubber bridge the deal is not scored and the turn to deal passes to the next player, while in duplicate the score is recorded as zero for each pair and returned to the board.

Strategy

The purpose of some early bids may be to exchange information rather than to set the final contract. For most players, many calls (bids, doubles and redoubles, and sometimes even passes) are not made with the intention that they become the final contract, but to describe the strength and distribution of the player's hand, so that the partnership can reach an informed conclusion on their best contract, and/or to obstruct the opponents' bidding. The set of agreements used by a partnership about the meaning of each call is referred to as a bidding system, full details of which must be made available to the opponents; 'secret' systems are not allowed. An opponent can ask the bidder's partner to explain the meaning of the call.

Example

West	North	East	South
Pass	1♥	Pass	1♠
Pass	2♦	Dbl	3♠
Pass	4♠	Pass	Pass
Pass

In the example at left, West was the dealer and so first to call, when he passed. North opened the bidding, which proceeded as shown to a 4♠ contract, with spades the trump suit. South, having been the first to bid spades, became the declarer. East-West become the defenders and West becomes the opening leader, after which North, the dummy, displays his cards. Ten tricks are required by North-South, the book plus the 4-level bid. Since East's double of 2♦ was cancelled by the subsequent South's 3♠ bid, it does not affect the contract.

Play of the cards

See also: Opening lead

The contract level sets a specific target: in the example above, the declarer must attempt to win ten tricks (the assumed "book" of six, plus four as bid, with spades as trumps), to make the contract and get a positive score. Success in this goal is rewarded by points in the scoring phase for the declarer's side. If the declarer fails to make the contract, the defenders are said to have set or defeated the contract (declarer has gone down), and are awarded points for doing so.

To begin play, the defender on the declarer's left makes the opening lead. In more formal play, the opening leader does so by first placing the card face down on the table to afford his partner an opportunity to ask questions about the auction, then faces it when partner has no further questions. This practice also allows the defender to return the card to his hand without penalty if the lead is not his to make.

The dummy then spreads his hand on the table with each suit in a column from highest to lowest facing the declarer, customarily with any trump suit on declarer's left and the colors of the suits alternating. The rules of play are similar to other trick-taking games, except that the declarer directs the play of cards from the dummy in addition to playing cards from his own hand. Dummy is allowed to try to prevent declarer from infringing the rules, but otherwise must not interfere with the play; for example, dummy may attempt to prevent declarer from leading from the wrong hand (by stating, e.g., "you won the last trick in dummy") but must not comment on opponents' actions or make suggestions as to play.

The hands play clockwise around the table, and each hand must "follow suit" (that is, play a card of the suit lead to the trick) if able. A hand that cannot follow suit may either "ruff" (play a trump) if there is a trump suit or "sluff" (discard a card of any other suit). The hand that plays either the highest trump or, in a trick that contains no trumps, the highest card of the suit led to the trick (1) wins the trick for its side and (2) proceeds to lead to the next trick. The play continues until all thirteen tricks are played. If confident that he will win all or a specific number of the remaining tricks, (for example because he holds all the outstanding trumps), the declarer or a defender may "claim" them by showing his hand and stating the number and how he will take them.

In rubber bridge, one player typically gathers the tricks for each side. In duplicate bridge, each player retains the card played from his hand to each trick and lays it on the table turned in the direction of the side that won the trick, thus keeping the hands separate to return them to the board at the end of play.

If upon reviewing dummy after the opening lead, declarer assesses that he does not have enough "top tricks" immediately available to make his contract, he can try to develop additional tricks through a variety of methods. These include:

• losing tricks to the defenders' high cards in order to "promote" the remaining cards of that suit in his hand and dummy.
• taking the tricks in his long suits after the defenders' cards in that suit are exhausted, to force defenders to show their distribution and discard useful cards.
• the "finesse", in which a low card is led toward a high card in partner's hand, in the hope of trapping a high card held by the defender who must play in between.
• in trump contracts, the declarer may attempt to cover losers in his hand by trumping them in dummy, while also taking care to draw out the defenders' trumps where necessary.
• cutting communications between the two defenders, for instance by allowing them to win early tricks in a suit using up the cards in one hand until they are unable to use the suit as an entry to winners in the other hand.
• more advanced techniques include the "squeeze play" in which a defender is forced to choose which card to discard before declarer has to make his own discard choice.

Defense

Defense is the play of the cards by the non-declaring partnership, with the goal of preventing the opponents achieving their contract. Bridge writer Edwin B. Kantar wrote "There is no question that defense is the most difficult aspect of playing bridge."

Of particular importance is the first defensive move, the opening lead made by the player sitting left of the declarer. There is an extensive bridge literature on the choice of opening leads. As play proceeds, defending partners can try to convey information about their hands through various systems of signals. A higher card discarded on a trick might, for example, encourage partner to continue leading that suit, whereas a lower card would be discouraging.

Good defense is particularly dependent upon partnership agreements and effective cooperation between the partners. As a result, longer-term partnerships tend to develop the most effective defensive play.

Scoring

Main article: Bridge scoring

When play ends, the score is determined by comparing the number of tricks won by the declaring side to the number required to satisfy the contract. The available scoring points for the declaring side are dependent upon both the level and strain of the contract and are awarded to them only when the contract is 'made', i.e. at least the contracted for number of tricks are won. If the declaring side fails to take the required number of tricks, defending side receives points instead for "setting" (or "defeating") the contract.

When the declarer makes the contract, the declarer's side receives points for:

• Every odd trick bid and made, known as contract points
• Each overtrick, i.e. each trick taken over the contract level, known as overtrick points
• Bonus points dependent upon the game variant being played for certain contract levels including part-game, game, small slam and grand slam contracts as well as for winning the rubber
• Bonus points in some game variants for making a doubled or redoubled contract
• Bonus points in some game variants for holding four or more honors in one hand

When the declarer fails to make the contract, the defending side receives points for undertricks – the number of tricks by which declarer fell short of the goal.

The various bonus structures give certain bid levels special significance. For example, if the declarer takes all thirteen tricks in a notrump contract, there is a large score difference between contracts of 1NT and 7NT. The bonuses available for contracting at higher levels ensures competitiveness in the auction. The most important level is game, which is any contract whose bid trick value is 100 or more points. Game level varies by suit, since different suits are worth different amounts in scoring. The game level for notrump is three, the game level for hearts or spades (the major suits) is four, and the game level for clubs or diamonds (the minor suits) is five. Because of the value of the game bonus, much of the bidding revolves around investigating the possibility of making game. Additional bonuses are awarded for bidding and making small slam (level 6, i.e. 12 tricks) and grand slam (level 7, i.e. all 13 tricks) contracts.

The concept of vulnerability affects scoring and introduces a wider range of tactics in bidding and play. Every partnership is in one of two states: vulnerable or non-vulnerable, either by virtue of their previous deals in rubber bridge or as predetermined by the board in duplicate bridge. When a pair is vulnerable, game and slam bonuses are higher, as are penalties for failure to make the contract. Finally, doubling and redoubling also has a significant effect on scoring, especially for vulnerable contract which are either defeated or which win overtricks.

While the scoring of individual hands in rubber and duplicate bridge share many features, the accumulation of scores over several hands differs significantlly. See bridge scoring for details and examples.

Rules

The rules of the game are referred to as the 'Laws' as promulgated by various bridge organizations.

Laws of duplicate bridge

Main article: Laws of Duplicate Bridge

The official rules of duplicate bridge are promulgated by the World Bridge Federation (WBF) as the "International Code of Laws of Duplicate Bridge, 2007". The Laws Committee of the WBF, composed of world experts, updates the Laws every 10 years; it also issues a Laws Commentary advising on interpretations it has rendered.

In addition to the basic rules of play, there are many additional rules covering playing conditions and the rectification of irregularities which are primarily for use by tournament directors who act as referees and have overall control of procedures during competitions. In addition, some details of procedure are left to the discretion of the zonal bridge organisation for tournaments under their aegis and some (for example, the choice of movement) to the sponsoring organisation (e.g. the club).

The zonal organisations of the WBF also publish editions of the Laws. For example, the American Contract Bridge League publishes "Laws of Duplicate Bridge, 2008", "Laws of Contract Bridge, 2003" and additional supporting documentation including: Director Decisions, Tech Files and Casebook (appeals from national bridge championships).

Rules of rubber bridge

There are no universally accepted rules for rubber bridge promulgated by bridge governing bodies; instead local rules such as The Laws of Contract Bridge as published by the American Contract Bridge League constitute the rules for those wishing to abide by a published standard.

The majority of rules mirror those of duplicate bridge in the bidding and play and differ primarily in procedures for dealing and scoring.

Laws of online play

In 2001, the World Bridge Federation promulgated a set of Laws for online play.

History

Main article: History of contract bridge

Bridge club at Shimer College, 1942.

Bridge is a member of the family of trick-taking games and is a development of Whist, which had become the dominant such game enjoying a loyal following for centuries. According to the Oxford English Dictionary, Bridge is the English pronunciation of a game called Biritch, which was also known as Russian Whist.

The oldest known Biritch rule book dated 1886 is Biritch, or Russian Whist by John Collinson. It and his subsequent letter to The Saturday Review dated May 28, 1906, document the origin of Biritch as from the Russian community in Istanbul and having some features in common with Solo Whist. The game had many significant bridge-like developments: dealer chose the trump suit, or nominated his partner to do so; there was a call of notrumps (biritch); dealer's partner's hand became dummy; points were scored above and below the line; game was 3NT, 4H and 5D (although 8 club odd tricks and 15 spade odd tricks were needed); the score could be doubled and redoubled; and there were slam bonuses. This game, and variants of it known as "bridge" and "bridge-whist", became popular in the United States and the UK in the 1890s despite the long-established dominance of whist.

In 1904 auction bridge was developed, in which the players bid in a competitive auction to decide the contract and declarer. The object became to make at least as many tricks as were contracted for and penalties were introduced for failing to do so.

The modern game of contract bridge was the result of innovations to the scoring of auction bridge made by Harold Stirling Vanderbilt and others. The most significant change was that only the tricks contracted for were scored below the line toward game or a slam bonus, a change that resulted in bidding becoming much more challenging and interesting. Also new was the concept of "vulnerability", making sacrifices to protect the lead in a rubber more expensive. The various scores were adjusted to produce a more balanced and interesting game. Vanderbilt set out his rules in 1925, and within a few years contract bridge had so supplanted other forms of the game that "bridge" became synonymous with "contract bridge."

In the USA, most of the bridge played today is duplicate bridge, which is played at clubs, in tournaments and online. In the UK, rubber bridge is still popular in both homes and clubs, as is duplicate bridge. The number of people playing contract bridge has declined since its peak in the 1940s, when a survey found it was played in 44% of US households. The game is still played, especially amongst retirees, and in 2005 the ACBL estimated there were 25 million players in the US.

Tournaments

Bridge is a game of skill played with randomly dealt cards, which makes it also a game of chance, or more exactly, a tactical game with inbuilt randomness, imperfect knowledge and restricted communication. The chance element is in the deal of the cards; in competitions and clubs the chance element is largely eliminated by comparing results of multiple pairs in identical situations. This is achievable when there are eight or more players, sitting at two or more tables, and the deals from each table are preserved and passed to the next table, thereby duplicating them for the next table of participants to play. At the end of a session, the scores for each deal are compared, and the most points are awarded to the players doing the best with each particular deal. This measures skill because each player is being judged only on the ability to bid with, and play, the same cards as other players. However very often even the most skillful play will only succeed some of the time, and the skilled player may be unlucky because an alternative, less expert play achieves a better result. But in the long run the expert player will score better.

This form of the game is referred to as duplicate bridge and is played in clubs and tournaments, which can gather as many as several hundred players. Duplicate bridge is a mind sport, and its popularity gradually became comparable to that of chess, with which it is often compared for its complexity and the mental skills required for high-level competition. Bridge and chess are the only "mind sports" recognized by the International Olympic Committee, although they were not found eligible for the main Olympic program.

The basic premise of duplicate bridge had previously been used for whist matches as early as 1857. Initially, bridge was not thought to be suitable for duplicate competition; it wasn't until the 1920s that (auction) bridge tournaments became popular.

In 1925 when contract bridge first evolved, bridge tournaments were becoming popular, but the rules were somewhat in flux, and several different organizing bodies were involved in tournament sponsorship: the American Bridge League (formerly the American Auction Bridge League, which changed its name in 1929), the American Whist League, and the United States Bridge Association. In 1935, the first officially recognized world championship was held. By 1937, however, the American Contract Bridge League had come to power (a union of the ABL and the USBA), and it remains the principal organizing body for bridge tournaments in North America. In 1958, the World Bridge Federation was founded to promote bridge world-wide, coordinate periodic revision to the Laws (each ten years, next in 2017) and conduct world championships.

Bidding boxes and bidding screens

Bidding box

In tournaments, "bidding boxes" are frequently used, as noted above. In top national and international events, "bidding screens" are used. These are placed diagonally across the table, preventing partners from seeing each other during the game; often the screen is removed after the auction is complete.

Game strategy

Bidding

Main articles: Bidding system and Bridge convention

Much of the complexity in bridge arises from the difficulty of arriving at a good final contract in the auction. This is a difficult problem: the two players in a partnership must try to communicate sufficient information about their hands to arrive at a makeable contract, but the information they can exchange is restricted – information may be passed only by the calls made and later by the cards played, not by other means; in addition, the agreed-upon meaning of each call and play must be available to the opponents.

Since a partnership that has freedom to bid gradually at leisure can exchange more information, and since a partnership that can interfere with the opponents' bidding (as by raising the bidding level rapidly) can cause difficulties for their opponents, bidding systems are both informational and strategic. It is this mixture of information exchange and evaluation, deduction, and tactics that is at the heart of bidding in bridge.

A number of basic rules of thumb in bridge bidding and play are summarized as bridge maxims.

Bidding systems and conventions

A bidding system is a set of partnership agreements on the meanings of bids. A partnership's bidding system is usually made up of a core system, modified and complemented by specific conventions (optional customizations incorporated into the main system for handling specific bidding situations) which are pre-chosen between the partners prior to play. The line between a well-known convention and a part of a system is not always clear-cut: some bidding systems include specified conventions by default. Bidding systems can be divided into mainly natural systems such as Acol and Standard American, and mainly artificial systems such as the Precision Club and Strong Diamond (see Strong Diamond).

Calls are usually considered to be either natural or conventional (artificial). A natural bid is one in which the suit and level bid is essentially passing the information "I have some cards in this suit and (usually) some high cards in my hand"; a natural double says in effect "I don't think the opponents can make their contract, so I want to raise the stakes". By contrast, a conventional (artificial) call offers and/or asks for information by means of pre-agreed coded interpretations, in which some calls convey very specific information or requests that are not part of the natural meaning of the call. Thus in response to 4NT, a 'natural' bid of 5♦ would state a preference towards a diamond suit or a desire to play the contract in 5 diamonds, whereas if the partners have agreed to use the common Blackwood convention, a bid of 5♦ in the same situation would say nothing about the diamond suit, but tell the partner that the hand in question contains exactly one ace.

Conventions are valuable in bridge because of the need to pass information beyond a simple like or dislike of a particular suit, and because the limited bidding space can be used more efficiently by taking situations in which a given call will have less utility, because the information it would convey is not valuable or because the desire to convey that information would arise only rarely, and giving that call an artificial meaning that conveys more useful (or more frequently useful) information. There are a very large number of conventions from which players can choose; many books have been written detailing bidding conventions. Well-known conventions include Stayman (to ask for the showing of any 4 card major suit in a 1NT opener's hand), Jacoby transfers (a request by the weak hand for the stronger partner to bid a particular suit first, and therefore to become the declarer), and the Blackwood convention (to ask for information on the number of aces and kings held, used in slam bidding situations).

The term preempt refers to a high level tactical bid by a weak hand, relying upon a long suit rather than high-value cards for tricks. Preemptive bids serve a double purpose – they allow players to indicate they are bidding on the basis of a long suit in an otherwise weak hand, which is important information to share, and they also consume substantial bidding room before a possibly strong opposing pair can identify whether they have a good possibility to play the hand, or in what suit or at what level they should do so. Several systems include the use of opening bids or other early bids with weak hands including long (usually six to eight card) suits at the 2, 3 or even 4 or 5 levels as preempts.

Basic natural systems

As a rule, a natural suit bid indicates a holding of at least four (or more, depending on the situation and the system) cards in that suit as an opening bid, or a lesser number when supporting partner; a natural NT bid indicates a balanced hand.

Most systems use a count of high card points as the basic evaluation of the strength of a hand, refining this by reference to shape and distribution if appropriate. In the most commonly used point count system, aces are counted as 4 points, kings as 3, queens as 2, and jacks as 1 point; therefore, the deck contains 40 points. In addition, the distribution of the cards in a hand into suits may also contribute to the strength of a hand and be counted as distribution points. A better than average hand, containing 12 or 13 points, is usually considered sufficient to open the bidding, i.e., to make the first bid in the auction. A combination of two such hands (i.e., 25 or 26 points shared between partners) is often sufficient for a partnership to bid, and generally to make, game in a major suit or notrump (more are usually needed for a minor suit game, as the level is higher).

In natural systems, a 1NT opening bid usually reflects a hand that has a relatively balanced shape (usually between two and four (or less often five) cards in each suit) and a sharply limited number of high card points, usually somewhere between 12 and 18 – the most common ranges use a span of exactly three points, (e.g., 12-14, 15-17 or 16-18), but some systems use a four-point range, usually 15-18.

Opening bids of three or higher are preemptive bids, i.e., bids made with weak hands that especially favor a particular suit, opened at a high level in order to define the hand's value quickly and to frustrate the opposition. For example, a hand of ♠ KQJ9872 ♥ 7 ♦ 42 ♣ 763 would be a candidate for an opening bid of 3♠, designed to make it difficult for the opposing team to bid and find their optimum contract even if they have the bulk of the points, as it is nearly valueless unless spades are trumps, it contains good enough spades that the penalty for being set should not be higher than the value of an opponent game, and the high card weakness makes it more likely that the opponents have enough strength to make game themselves.

Openings at the 2 level are either unusually strong (2NT, natural, and 2♣, artificial) or preemptive, depending on the system. Unusually strong bids communicate an especially high number of points (normally 20 or more) or a high trick-taking potential (normally 8 or more).

Opening bids at the one level are made with hands containing 12–13 points or more and which are not suitable for one of the preceding bids. Using Standard American with 5-card majors, opening hearts or spades usually promises a 5-card suit. Partnerships who agree to play 5-card majors open a minor suit with 4-card majors and then bid their major suit at the next opportunity. This means that an opening bid of 1♣ or 1♦ will sometimes be made with only 3 cards in that suit.

Doubles are sometimes given conventional meanings in otherwise mostly natural systems. A natural, or penalty double, is one used to try to gain extra points when the defenders are confident of setting (defeating) the contract. The most common example of a conventional double is the takeout double of a low-level suit bid, implying support for the unbid suits or the unbid major suits and asking partner to choose one of them.

Variations on the basic themes

Bidding systems depart from these basic ideas in varying degrees. Standard American, for instance, is a collection of conventions designed to bolster the accuracy and power of these basic ideas, while Precision Club is a system that uses the 1♣ opening bid for all or almost all strong hands (but sets the threshold for "strong" rather lower than most other systems – usually 16 high card points) and may include other artificial calls to handle other situations (but it may contain natural calls as well). Many experts today use a system called 2/1 game forcing (enunciated as two over one game forcing), which amongst other features adds some complexity to the treatment of the one notrump response as used in Standard American. In the UK, Acol is the most common system; its main features are a weak one notrump opening with 12-14 high card points and several variations for 2-level openings.

There are also a variety of advanced techniques used for hand evaluation. The most basic is the Milton Work point count, (the 4-3-2-1 system detailed above) but this is sometimes modified in various ways, or either augmented or replaced by other approaches such as losing trick count, honor point count, law of total tricks, or Zar Points.

Common conventions and variations within natural systems include:

• Point count required for 1 NT opening bid ('mini' 10-12, 'weak' 12-14, 'strong' 15-17 or 16-18)
• Whether an opening bid of 1♥ and 1♠ requires a minimum of 4 or 5 cards in the suit (4 or 5 card majors)
• Whether 1♣ (and sometimes 1♦) is 'natural' or 'suspect' (also called 'phoney' or 'short'), signifying an opening hand lacking a notable heart or spade suit
• Whether opening bids at the two level are 'strong' (20+ points) or 'weak' (i.e., pre-emptive with a 6 card suit). (Note: an opening bid of 2♣ is usually played in otherwise natural systems as conventional, signifying any exceptionally strong hand)
• Blackwood (either the original version or Roman Key Card)
• Stayman (together with Blackwood, described as "the two most famous conventions in Bridge".)
• Whether the partnership will play Jacoby transfers (bids of 2♦ and 2♥ over 1NT or 3♦ and 3♥ over 2NT respectively require the 1NT or 2NT bidder to rebid 2♥ and 2♠ or 3♥ and 3♠), minor suit transfers (bids of 2♠ and either 2NT or 3♣ over 1NT respectively require the 1NT bidder to bid 3♣ and 3♦) and Texas transfers (bids of 4♦ and 4♥ respectively require the 1NT, or 2NT bidder to rebid 4♥ and 4♠)
• What types of cue bids (e.g. rebidding the opponents' suit) the partnership will play, if any.
• Whether doubling a contract at the 1, 2 and sometimes higher levels signifies a belief that the opponents' contract will fail and a desire to raise the stakes (a penalty double), or an indication of strength but no biddable suit coupled with a request that partner bid something (a takeout double).
• Whether doubling or overcalling over opponents' 1NT is natural or conventional. Most common artificial agreement is Cappelletti, where 2♣ is a transfer to be passed or corrected to a major, 2♦ means both majors and a major shows that suit plus a minor.
• How the partnership's bidding practices will be varied if their opponents intervene or compete.
• Which (if any) bids are forcing and require a response.

Within play, it is also commonly agreed what systems of opening leads, signals and discards will be played:

• Conventions for the opening lead govern how the first card to be played will be chosen and what it will mean,
• Signals indicate how cards played within a suit are chosen – for example, playing a noticeably high card when this would not be expected can signal encouragement to continue playing the suit, and a low card can signal discouragement and a desire for partner to choose some other suit. (Some partnerships use "reverse" signals, meaning that a noticeably high card discourages that suit and a noticeably low card encourages that suit, thus not "wasting" a potentially useful intermediate card in the suit of interest.)
• Discards cover the situation when a defender cannot follow suit and therefore has free choice what card to play or throw away. In such circumstances the thrown-away card can be used to indicate some aspect of the hand, or a desire for a specific suit to be played.
• Count signals cover the situation when a defender is following suit (usually to a suit that the declarer has led). In such circumstances the order in which a defender plays his spot cards will indicate whether an even or odd number of cards was originally held in that suit. This can help the other defender count out the entire original distribution of the cards in that suit. It is sometimes critical to know this when defending.
• Suit preference signals cover the situation where a defender is returning a suit which will be ruffed by his partner. If he plays a high card he is showing an entry in the higher side suit and vice versa. There are some other situations where this tool may be used.
• Surrogate signals cover the situation when it is critical to show length in a side suit and it will be too late if defenders wait till that suit is played. Then, the play in the first declarer played suit is a count signal regarding the critical suit and not the trump suit itself. In fact, any signal made about a suit in another suit might be called as such.

Advanced bidding techniques

Every call (including "pass", also sometimes called "no bid") serves two purposes. It confirms or passes some information to a partner, and also denies by implication any other kind of hand which would have tended to support an alternative call. For example, a bid of 2NT immediately after partner's 1NT not only shows a balanced hand of a certain point range, but also would almost always deny possession of a five-card major suit (otherwise the player would have bid it) or even a four card major suit (in that case, the player would probably have used the Stayman convention).

Likewise, in some partnerships the bid of 2♥ in the sequence 1NT - 2♣ - 2♦ - 2♥ between partners (opponents passing throughout) explicitly shows five hearts but also confirms four cards in spades: the bidder must hold at least five hearts to make it worth looking for a heart fit after 2♦ denied a four card major, and with at least five hearts, a Stayman bid must have been justified by having exactly four spades, the other major (since Stayman (as used by this partnership) is not useful with anything except a four card major suit). Thus an astute partner can read much more than the surface meaning into the bidding. Alternatively, many partnerships play this same bidding sequence as "Crawling Stayman" by which the responder shows a weak hand (less than eight high card points) with shortness in diamonds but at least four hearts and four spades; the opening bidder may correct to spades if that appears to be the better contract.

The situations detailed here are extremely simple examples; many instances of advanced bidding involve specific agreements related to very specific situations and subtle inferences regarding entire sequences of calls.

Play techniques

Main article: List of play techniques (bridge)

Terence Reese, a prolific author of bridge books, points out that there are only four ways of taking a trick by force, two of which are very easy:

• playing a high card that no one else can beat
• trumping an opponent's high card
• establishing long suits (the last cards in a suit will take tricks if the opponents don't have the suit and are unable to trump)
• playing for the opponents' high cards to be in a particular position (if their ace is to the right of your king, your king may be able to take a trick, especially if, when that suit is led, the player to your right has to play their card before you do)

Nearly all trick-taking techniques in bridge can be reduced to one of these four methods. The optimum play of the cards can require much thought and experience and is the subject of whole books on bridge.

Example

The cards are dealt as shown in the bridge hand diagram; North is the dealer and starts the auction which proceeds as shown in the bidding table.

Example 1 Matchpoints South in 4♥ Not Vulnerable		♠	J 3
		♥	J 8 7 4
		♦	A 10 7 6 5
		♣	Q 3
♠	K Q 8 7 2	N W               E S		♠	10 9 5 4
♥	A 2			♥	9 6
♦	J 4 2			♦	K Q 9
♣	10 7 2			♣	K 9 6 4
Lead: ♠ K		♠	A 6
		♥	K Q 10 5 3
		♦	8 3
		♣	A J 8 5

West	North	East	South
	Pass	Pass	1♥
1♠	2♥	2♠	3♣
Pass	4♥	Pass	Pass
Pass

As neither North nor East have sufficient strength to open the bidding, they each pass, denying such strength. South, next in turn, opens with the bid of 1♥, which denotes a reasonable heart suit (at least 4 or 5 cards long, depending on the bidding system) and at least 12 high card points. On this hand, South has 14 high card points. West overcalls with 1♠, since he has a long spade suit of reasonable quality and 10 high card points (an overcall can be made on a hand that is not quite strong enough for an opening bid). North supports partner's suit with 2♥, showing heart support and about 6-8 points. East supports spades with 2♠. South inserts a game try of 3♣, inviting the partner to bid the game of 4♥ with good club support and overall values. North complies, as North is at the higher end of the range for his 2♥ bid, and has a fourth trump (the 2♥ bid promised only three), and the doubleton queen of clubs to fit with partner's strength there. (North could instead have bid 3♥, indicating not enough strength for game, asking South to pass and so play 3♥.)

In the auction, North-South are trying to investigate whether their cards are sufficient to make a game (nine tricks at notrump, ten tricks in hearts or spades, 11 tricks in clubs or diamonds), which yields bonus points if bid and made. East-West are competing in spades, hoping to play a contract in spades at a low level. 4♥ is the final contract, 10 tricks being required for N-S to make with hearts as trump.

South is the declarer, having been first to bid hearts, and the player to South's left, West, has to choose the first card in the play, known as the opening lead. West chooses the spade king because spades is the suit the partnership has shown strength in, and because they have agreed that when they hold two touching honors (or adjacent honors) they will play the higher one first. West plays the card face down, to give their partner and the declarer (but not dummy) a chance to ask any last questions about the bidding or to object if they believe West is not the correct hand to lead. After that, North's cards are laid on the table and North becomes dummy, as both the North and South hands will be controlled by the declarer. West turns the lead card face up, and the declarer studies the two hands to make a plan for the play. On this hand, the trump ace, a spade, and a diamond trick must be lost, so declarer must not lose a trick in clubs.

If the ♣K is held by West, South will find it very hard to prevent it making a trick (unless West leads a club). However, there is an almost-equal chance that it is held by East, in which case it can be 'trapped' against the ace, and will be beaten, using a tactic known as a finesse.

After considering the cards, the declarer directs dummy (North) to play a small spade. East plays low (small card) and South takes the ♠A, gaining the lead. (South may also elect to duck, but for the purpose of this example, let us assume South wins the ♠A at trick 1). South proceeds by drawing trump, leading the ♥K. West decides there is no benefit to holding back, and so wins the trick with the ace, and then cashes the ♠Q. For fear of conceding a ruff and discard, West plays the ♦2 instead of another spade. Declarer plays low from the table, and East scores the ♦Q. Not having anything better to do, East returns the remaining trump, taken in South's hand. The trumps now accounted for, South can now execute the finesse, perhaps trapping the king as planned. South enters the dummy (i.e. wins a trick in the dummy's hand) by leading a low diamond, using dummy's ♦A to win the trick, and leads the ♣Q from dummy to the next trick. East covers the queen with the king, and South takes the trick with the ace, and proceeds by cashing the remaining master ♣J. (If East doesn't play the king, then South will play a low club from South's hand and the queen will win anyway, this being the essence of the finesse). The game is now safe: South ruffs a small club with a dummy's trump, then ruffs a diamond in hand for an entry back, and ruffs the last club in dummy (sometimes described as a crossruff). Finally, South claims the remaining tricks by showing his or her hand, as it now contains only high trumps and there's no need to play the hand out to prove they are all winners.

(The trick-by-trick notation used above can be also expressed in tabular form, but a textual explanation is usually preferred in practice, for reader's convenience. Plays of small cards or discards are often omitted from such a description, unless they were important for the outcome).

North-South score the required 10 tricks, and their opponents take the remaining three. The contract is fulfilled, and North enters the pair numbers, the contract, and the score of +420 for the winning side (North is in charge of bookkeeping in duplicate tournaments) on the traveling sheet. North asks East to check the score entered on the traveller. All players return their own cards to the board, and the next deal is played.

On the prior hand, it is quite possible that the ♣K is held by West. For example, by swapping the ♣K and ♥A between the defending hands. Then the 4♥ contract would fail by one trick (unless West had led a club early in the play). However the failure of the contract would not mean that 4♥ is a bad contract on this hand. The contract depends on the club finesse working, or a mis-defense. The bonus points awarded for making a game contract far outweigh the penalty for going one off, so it is best strategy in the long run to bid game contracts such as this one.

Similarly, there is a minuscule chance that the ♣K is in the west hand, but the west hand has no other clubs. In that case, declarer can succeed by simply cashing the ♣A, felling the ♣K and setting up the ♣Q as a winner. However the chance of this is far lower than the simple chance of approximately 50% that East started with the ♣K. Therefore, the superior percentage play is to take the club finesse, as described above.

Computer bridge

Main article: Computer bridge

User-based play

After many years of little progress, computer bridge made great progress at the end of the 20th century. In 1996, the American Contract Bridge League (ACBL) initiated official World Championships Computer Bridge, to be held annually along with a major bridge event. The first Computer Bridge Championship took place in 1997 at the North American Bridge Championships in Albuquerque, New Mexico.

Strong bridge playing programs such as Jack (World Champion in 2001, 2002, 2003, 2004, 2006 and 2009), Wbridge5 (World Champion in 2005, 2007 and 2008), RoboBridge and many-time finalist Bridge Baron, would probably rank among the top few thousand human pairs worldwide. A series of articles published in 2005 and 2006 in the Dutch bridge magazine IMP describes matches between Jack and seven top Dutch pairs. A total of 196 boards were played. Overall, the program Jack lost, but by a small margin (359 versus 385 imps).

Internet-based play

There are several free and subscription-based services available for playing bridge on the internet. For example:

• OKbridge is the oldest of the still-running internet bridge services: was established as a commercial enterprise in 1994, but the program started to be used interactively in August 1990 on players of all standards. Beginners to world class may be found playing there. OKbridge is a subscription-based club, with services such as customer support and ethics reviews.
• SWAN Games was founded April, 2000. In March 2004, announced a partnership to provide internet services to SBF members and is a competitor in subscription-based online bridge clubs.
• Bridge Base Online (BBO) is the most active online bridge club in the world, with more than 100 000 daily connections and 500 000 hands played each day. in part because it is free to play regular games and volunteer-run tournaments.

These and other sites offer various features, such as opportunities to earn ACBL masterpoints, to play in online tournaments, to compile lists of friends, and to earn money playing Bridge. Bridge Base Online also has a Vugraph feature showing tournaments from around the world for anyone interested to watch live. As well as written commentaries from top level players, voice commentaries have been incorporated since mid-2011. Software and hardware has been tested in 2011 in order to have digital cameras recognize the cards being played, which will avoid human error or delay.

Some national contract bridge organizations now offer online bridge play to their members, including the English Bridge Union, the Dutch Bridge Federation and the Australian Bridge Federation. MSN and Yahoo! Games have several online rubber bridge rooms. In 2001, World Bridge Federation issued a special edition of the lawbook adapted for internet and other electronic forms of the game.

Advantages of online play include:

• The software prevents improper plays and calls, such as insufficient bids, revokes (failure to follow suit when able), and actions out of turn.
• Unauthorised information cannot be passed by tone of voice or body language (but can much more easily be passed by external communication).
• Detailed records are kept which can aid partners to review and improve their bidding and play.
• Hands can be easily be analysed for best play (double dummy) afterwards.
• Can play with partners far away - or across town.
• No need to assemble 4 people in one place.
• Faster play - no shifting chairs or waiting for shuffles.
• Player rating systems may attempt to measure ability without regard to the number of games played or the number of years spent accumulating masterpoints.
• Fewer restrictions on the conventions that are permitted compared to club tourneys.
• Easy to find opponents for practice in bidding and playing.
• You will meet bridge players from every country and time zone.
• Flexibility when to play (24/7), and choice of opponent skill level.
• Choice of individual, pairs, or team competitions.
• Fun to watch famous bridge stars play "live" as well as well-known personalities such as Bill Gates and Warren Buffett (who used to appear regularly on OKBridge in set games)

There are also a number of disadvantages:

• Inability to decide on bidding convention ahead of time when partners are strangers.
• A reduced social element.
• Players may leave before a hand finishes, or in the middle of a planned session, either intentionally or because of connection difficulties.

Tournaments are usually shorter online. A common length is 12 boards(deals). Online services support many simultaneous tournaments. When you finish one tournament, another will start soon.

Some online services like BBO have apps for Android and iPhone.

Card games related to bridge

• 500
• Bridgette
• Euchre

• King
• Lanterloo
• Nap

• Ombre
• Quadrille

• Skat
• Spoil Five
• Whist

See also

• Glossary of contract bridge terms
• List of bridge books
• List of bridge competitions and awards

• List of bridge magazines
• List of contract bridge people

Further reading

Further information: List of bridge books

External links

• American Contract Bridge League (ACBL)
• New Zealand Contract Bridge Association (NZCBA)
• World Bridge Federation (WBF)