| Much of the complexity in bridge arises from the | | | | Pre-emptive bids serve a double purpose - they allow |
| difficulty of arriving at a good final contract in the | | | | a player to indicate they are bidding on the basis of a |
| auction. This is a difficult problem: the two players in a | | | | long suit in an otherwise weak hand, which is important |
| partnership must try to communicate sufficient | | | | information to share, and also effectively raises the |
| information about their hands to arrive at a makeable | | | | stakes before a possibly strong opposition can identify |
| contract, but the information they can exchange is | | | | whether they have a good possibility to play the hand. |
| restricted - information may only be passed by the | | | | Several systems include bids on weak hands with 6 or |
| calls made and later by the cards played, not by other | | | | 7 card suits at the 2, 3 or even 4 level, as preempts. |
| means; and the agreed upon meaning of all information | | | | Basic natural systems |
| passed must be available to the opponents. | | | | As a rule, a natural suit bid indicates a holding or at |
| Since a partnership who have freedom to bid gradually | | | | least 4 (or more depending on the system) cards in |
| at leisure can exchange more information, and a | | | | that suit as an opening bid (or a lesser number when |
| partnership who can interfere with their opponents | | | | supporting partner); a natural NT bid indicates a |
| bidding (or who raise the bidding level rapidly) can | | | | balanced hand. |
| cause difficulties for their opponents, bidding systems | | | | Most systems use a count of high card points as the |
| are both informational, and also strategic. It is this | | | | basic evaluation of the strength of a hand, refining this |
| mixture of information exchange and evaluation, | | | | by reference to shape and distribution if appropriate. |
| deduction, and strategy that is at the heart of bidding in | | | | Aces are counted as 4 points, kings as 3, queens as 2, |
| bridge. | | | | and jacks as 1 point; therefore, the deck contains 40 |
| Bidding systems and conventions | | | | points. In addition, the distribution of the cards in a hand |
| A bidding system is the typical solution to this problem: | | | | into suits may also contribute to the strength of a hand |
| each player evaluates their hand and their best | | | | and be counted as distribution points. A better than |
| strategy, in light of new information, and makes bids to | | | | average hand, containing 12 or 13 points, is usually |
| give or request information from their partner with the | | | | considered sufficient to open the bidding, i.e. make the |
| goal of arriving at an ideal contract. A bidding system is | | | | first bid in the auction. A combination of two such |
| usually made up of a core system (such as Acol, | | | | hands (i.e. 25 or 26 points shared between partners is |
| Standard American or Precision Club), modified and | | | | often sufficient for a partnership to bid, and generally |
| complemented by specific conventions (optional | | | | make, game in no trumps; more may be needed for a |
| customisations incorporated into the main system for | | | | suit game). |
| handling specific bidding situations) which are | | | | In natural systems a one no trump (1NT) opening bid |
| pre-chosen between the partners prior to playing. The | | | | usually reflects a hand that has a relatively balanced |
| line between a well known convention, and a part of a | | | | shape (usually between 2 and 4 cards in each suit) |
| system, is not always clear-cut, some bidding systems | | | | and a limited number of high card points, somewhere |
| include specified conventions by default. Bidding | | | | between 12 and 18 (normally a 3 point range e.g. 12-14, |
| systems can be divided into mainly natural systems | | | | 15-17 or 16-18). |
| such as Acol and Standard American, and mainly | | | | Opening bids of 3 or higher are preemptive (strategic) |
| artificial systems such as the Precision Club. | | | | bids, i.e. bids made with weak hands that especially |
| Bids are usually considered to be either natural or | | | | favor a particular suit, opened at a high level in order to |
| conventional (artificial). A natural bid is one where the | | | | frustrate the opposition. A hand of |
| suit and level bid is essentially passing the information "I | | | | ¦AK98742 |
| have this suit for you", or in the case of a double "I | | | | ¦73 |
| want to raise the stakes as I don't think the opponents | | | | ¦42 |
| can make their contract". By contrast, a conventional | | | | ¦76 would be an ideal |
| (artificial) bid offers and/or asks for information by | | | | candidate for an opening bid of |
| means of pre-agreed coded interpretations in which | | | | 3¦, designed to make it |
| some bids convey very specific information or | | | | difficult for the opposing team to bid and find their |
| requests which are not part of the natural meaning of | | | | Optimum contract even if they have the bulk of the |
| the bid. Thus in response to 4NT, a 'natural' bid of 5D | | | | points. |
| would state a preference towards a diamond suit or a | | | | Openings at the 2 level may be unusually strong (2NT, |
| desire to play the contract in 5 diamonds, whereas if | | | | natural, and 2C, artificial) or preemptive depending on |
| the partners are including 'Blackwood' in their system (a | | | | the system. Unusually strong bids communicate an |
| common convention), a bid of 5D in this situation would | | | | especially high number of points (normally 20 or more) |
| say nothing about the diamond suit; it would tell the | | | | or a high trick taking potential (normally 8 or more). |
| partner that the hand in question contains exactly one | | | | Opening bids at the one level are made with hands |
| ace. | | | | containing 12/13 points or more which are not suitable |
| Conventions are valuable in bridge because of the | | | | for one of the preceding bids - with some systems |
| need to pass information beyond the simple like or | | | | (e.g. Standard American or 5-card majors) a major suit |
| dislike of a named suit, and because the limited bidding | | | | opening shows a 5-card suit (5-card major convention, |
| space can be used more efficiently by taking situations | | | | in which an opening bid of |
| where a given bid will have less utility and giving that | | | | 1¦ or |
| bid an artificial meaning that conveys more strategically | | | | 1¦ promises at least 5 |
| useful information. There are a very large number of | | | | cards in that suit. This leads to some awkward bids, |
| conventions that players often choose from. Well | | | | for instance, when a player has four cards in each |
| known conventions include Stayman (to ask for the | | | | major, and is forced to open the bidding with 1 of a |
| show of any 4 card major suit in a 1NT opening hand), | | | | 3-card minor suit). |
| Jacoby Transfers (a strategic request by the weak | | | | Doubles are sometimes used in bidding conventions. A |
| hand for the stronger partner to bid and play the game | | | | natural, or penalty double, is one used to try to gain |
| instead), and Blackwood convention (to ask for | | | | extra points when the defenders are confident of |
| information on aces and kings in a slam bidding | | | | setting (defeating) the contract. The most common |
| situation). | | | | example of a conventional double is the takeout |
| The term 'preempt' (or pre-emptive bid) is used to | | | | double of a low-level suit bid, implying support for the |
| signify a high level tactical bid by a weak hand, relying | | | | unbid suits and asking partner to choose one of them. |
| upon a long suit rather than high value cards for tricks. | | | | |