The Copenhagen convention in the game of contract bridge is a conventional overcall which shows a two-suited hand. It was first devised by Mr. John Trelde and Mr. Gert Lenk, both of Copenhagen, Denmark. While it is rarely used in North America (where Michaels cuebids are most popular), it is fairly popular in Europe, especially Denmark.
The requirement for a bid in the Copenhagen convention is a two-suited hand with at least five cards in each suit and typically an opening hand. Point count requirements vary, but it is commonly agreed that an overcall using this convention is constructive and should be made on hands that hold the prospect of winning the auction. When made on very weak hands, the chances are the opponents will win the auction and will have been warned about the unbalanced holding, leading to games that would not have been bid otherwise. Given that a bid using the Copenhagen convention is forcing for one round, most partnerships apply no upper limit to its high card strength.
To use the convention, when the opponents make a one level opening, you make one of three bids. To show the bottom two unbid suits, bid 2 NT. To show the top and bottom unbid suits, bid 3♣. To show the top two unbid suits, bid 3♦. If the opponents have bid two suits, both at the one level, then the only overcall is 2 NT, which shows the two unbid suits.
As opposed to Michaels cuebids, the 3♣ and 3♦ jump overcalls aren't available as natural bids. Bids at the two level (barring 2 NT) are natural. The Copenhagen convention is more precise in terms of uniquely defining the specific suits denoted than standard Michaels cuebids. However, the lowest level the hand can be played at is the three level, and rarely will a nine card trump suit fit be found. This goes against the Law of Total Tricks, which states the three level should have at least a nine card fit. The Ghestem convention and its variants have similar advantages but also allow some fits to be found at the two level by using a cuebid at the 2 level rather than 3♦.
Standard American is a bidding system for the game of bridge widely used in North America and elsewhere. Owing to the popularization of the game by Charles Goren in the 1940s and 1950s, its early versions were sometimes referred to simply as 'Goren'. With the addition and evolution of various treatments and conventions, it is now more generally referred to as Standard American. It is a bidding system based on five-card majors and a strong notrump; players may add conventions and refine the meanings of bids through partnership agreements summarized in their convention card. One standardised version, SAYC, is widely used by casual partnerships and in online bridge.
In the card game of bridge, the unusual notrump is a conventional overcall showing a two-suited hand. It was originally devised by Al Roth in 1948 with Tobias Stone, to show the minor suits after the opponents opened in a major.
A bridge convention is an agreement about an artificial call or a set of related artificial calls. Calls made during the auction phase of a contract bridge game convey information about the player's card holdings. Calls may be "natural" or "artificial".
The Michaels cuebid is a conventional bid used in the card game contract bridge. First devised by Michael Michaels of Miami Beach, FL, it is an overcaller's cuebid in opponent's opening suit and is normally used to show a two-suited hand with at least five cards in each suit and eight or more points.
Preempt is a bid in contract bridge whose primary objectives are (1) to thwart opponents' ability to bid to their best contract, with some safety, and (2) to fully describe one's hand to one's partner in a single bid. A preemptive bid is usually made by jumping, i.e. skipping one or more bidding levels. Since it deprives the opponents of the bidding space, it is expected that they will either find a wrong contract of their own, or fail to find any. A preemptive bid often has the aim of a save, where a partnership bids a contract knowing it cannot be made, but assumes that, the penalty will still be smaller than the value of opponents' bid and made contract.
These terms are used in contract bridge, using duplicate or rubber scoring. Some of them are also used in whist, bid whist, the obsolete game auction bridge, and other trick-taking games. This glossary supplements the Glossary of card game terms.
The weak two bid is a common treatment used in the game of contract bridge, where an opening bid of two diamonds, hearts or spades signifies a weak hand, typically containing a long suit. It may be deployed within any system structure that offers a forcing artificial opening to handle hands of (eg) 20+ points, or an expectation of 8 or more tricks. It is form of preemptive bid.
In the card game contract bridge, a takeout double is a low-level conventional call of "Double" over an opponent's bid as a request for partner to bid his best of the unbid suits. The most common takeout double is after an opponent's opening bid of one of a suit where the double shows a hand with opening values, support for all three unbid suits and shortness in the suit doubled. Normally, the partner of the doubler must bid his best suit but may pass if (a) his right hand opponent intervenes or (b) on the more rare occasions when his hand is such that he wishes to convert the takeout double to a penalty double.
In the card game contract bridge, DONT is a conventional overcall used to interfere with an opponent's one notrump (1NT) opening bid. DONT, an acronym for Disturb Opponents' Notrump, was designed by Marty Bergen, and is therefore also referred to as "Bergen over Notrump". Although the method is often criticized for being too nebulous, it remains fairly popular. The convention was first published in the September/October 1989 issue of Bridge Today.
Bridge bidding systems that incorporate a strong 2 clubs opening bid include modern Standard American, standard Acol, 2/1 game forcing and many others.
Slam-seeking conventions are codified artificial bids used in the card game contract bridge. Bidding and making a small slam or grand slam yields high bonuses ranging from 500 to 1500 points. However, the risk is also high as failure to fulfill the slam contract also means failure to score the bonus points for a game (300-500). Conventions have been devised to maximise the opportunity for success whilst minimising the risk of failure.
The Raptor 1NT overcall over an opposing 1-level suit opening is a contract bridge convention that indicates a two-suited hand with exactly four cards in the unbid major and a longer suit in an unbid minor.
In the game of bridge, Ghestem is a conventional overcall structure, using 2NT, 3♣, and the (non-jump) cuebid over an opposing opening at the one level to denote two-suited hands in two of the remaining three suits.
In contract bridge, a cue bid is either a bid of the opponents' suit, or "slam seeking": a slam-investigating bid made during an auction's later rounds that shows control of a suit.
In contract bridge, an overcall is a bid made after an opening bid has been made by an opponent; the term refers only to the first such bid. A direct overcall is such a bid made by the player seated immediately to the left of the opener, i.e. next in the bidding rotation; an overcall in the 'last seat', i.e. by the player to the right of opener, which is made after two intervening passes, is referred to as a balancing or protective overcall.
EHAA is a highly natural bidding system in contract bridge characterized by four-card majors, sound opening bids, undisciplined weak two-bids in all four suits and a mini notrump, usually of 10–12 high card points.
Inverted minors refers to a treatment introduced by the Kaplan–Sheinwold (K–S) bidding system for the popular card game bridge. The original structure of Precision, another bidding system, also employed inverted minors over a 1♦ opening. However, the treatment is no longer restricted to users of these bidding systems. although partnerships that use a Short club system tend also to use the convention only after a 1♦ opener.
New Minor Forcing (NMF), is a contract bridge bidding convention used to find a 5-3 or 4-4 major suit fit after a specific sequence of bids in which opener has rebid one notrump. The convention is triggered by responder at his second turn by an artificial bid of two in an unbid minor; it requires that he hold five cards in the major he has previously bid and an unlimited hand ranging in value from at least game invitational strength to that sufficient to have interest in slam; he may also hold four cards in the other major. Accordingly, there are six bidding sequences in which the New Minor Forcing bid may be applied:
Unusual vs. unusual is a competitive bidding convention used in contract bridge by the opening side after an opponent has made an overcall showing two suits.
Astro is a contract bridge bidding convention used to intervene over an opponent's one notrump (1NT) opening bid. The name is derived from the initials of the surnames of its inventors - Paul Allinger, Roger Stern and Lawrence Rosler.