Bridge bidding systems that incorporate a strong 2 clubs opening bid include modern Standard American, standard Acol, 2/1 game forcing and many others.
In most natural bridge bidding systems, the opening bid of 2♣ is used exclusively for hands too strong for an opening bid at the one-level. Typically, the bid is reserved for hands that are almost strong enough to bid to the game level on their own power, or even stronger. The exact requirements for the bid vary considerably depending upon the system used and partnership agreement.
In most early bidding systems, opening bids of two of a suit signified a very strong hand and were referred to as strong two bids. [1] [2] However, pioneer bridge inventors like Pierre Albarran and David Burnstine [3] saw that the frequency of such bids is fairly low, and that a 2♣ bid can be used for all strong hands, leaving other two-level opening bids for other purposes (for example, weak two bids).
The strength requirements for the 2♣ bid differ slightly in different systems. In all cases they show a hand which is close to game forcing. For balanced hands, a 2♣ bid shows 22 or more points in Standard American (Yellow Card), and 23 or more points in standard Acol. For unbalanced hands, the typical strength is about 9 or more playing tricks, or 3 losers or less if using Losing-Trick Count.
With "natural" responses, which is the most commonly used treatment, the 2♦ bid is artificial and very weak (up to 6 HCP). All other bids are natural and positive. [4]
Some players alter or reverse the order of natural responses in order to preserve bidding space and allow for more accuracy in later bidding. There are several treatments in circulation:
"Three Point Step" responses to a strong 2♣ opening bid is another option. In this simple convention, the responder specifies the high card strength of his or her hand, without regard to distribution, as follows.
If requested, the explanation of an alert should describe the meaning of the bid completely; for example:
or
This convention for response has two significant advantages and two relatively minor disadvantages over other responses. The first advantage is that the 2♦ "Drop dead!" response alerts the opening bidder to partner's weakness immediately, while there's plenty of room to find a safe landing spot, when partner's hand is too weak to go on to game—which happens quite often in actual play. The second major advantage is that it immediately tells the opening bidder the combined high card strength of the two hands to within one HCP, and thus the most probable optimal level to which to bid (with the caveat that one sometimes can go a level higher with a good trump fit). The first drawback is that the weaker hand occasionally will end up declaring a contract with a trump fit in the major suit of the response. (Note that a transfer following opener's rebid of 2NT over a response of either 2♥ or 2♠ may be to the suit of the response. Such transfers cannot achieve the objective of making the strong hand the declarer, but they still help to find such a trump fit.) The second drawback is that it uses up some bidding space if the responder has an unusually strong hand. Nonetheless, opener's minimum of 22 HCP leaves a maximum of 18 HCP distributed among the other three hands. It's quite rare for responder to hold more than half of them. Indeed, this convention has gained popularity both for its simplicity (comparable to standard Blackwood) and for the infrequent occurrence and relatively minor consequences of its drawbacks.
The origin of this convention is uncertain. Some players have attributed it to Oswald Jacoby, of Jacoby Transfer and Jacoby 2NT fame, while others refer to it as "Castlebury" (or "Castleberry"?), but the present author is not aware of any source that would verify either attribution.
Some players prefer to show their controls (high cards) rather than suits in the response to 2♣ opening bid. This has an advantage in cases when the opener has a strong one- or two-suiter (i.e. has an interest in cover cards rather than finding the suit fit), but can take up bidding space and miss a suit fit when the opener is balanced or semi-balanced.
Some players play that 2♣ can also contain a weak variant, for example the 2♦ weak two bid. In this scheme, 2♦ by responder is a waiting bid, asking the opener to describe his hand further if he is strong. If the opening hand has a weak two bid in diamonds, he should pass. However, if the responder has a strong hand, typically 15 high card points or more, he responds with 2NT. This treatment is often subject to restrictions in tournament play, as it has a destructive potential—see Bridge convention#Regulations.
One major advantage of the artificial opening bid of 2♣ for all types of strong hands is that other opening bids at the two-level (2♦, 2♥ and 2♠) become available for weak two bids, thus eliminating many possible bids for the opponents. These weak two hands appear 20 times as often as the very strong hands, which illustrates the inefficiency of reserving all opening bids at the two-level for very strong hands.
An alternative is to use strong two bids for hands which are strong but not game forcing, which reduces the range of one-level openings and helps bidding accuracy. However, since weak twos are so useful, there are methods which allow weak twos in hearts and spades and use 2♦ to show a different range of strong hands; these are Benjaminised (Benji) Acol, Reverse Benji and the Multicoloured Two Diamonds.
Another advantage is the relative precision with which strong balanced hands can be bid. An opening bid of 2 NT indicates a balanced hand with 20-21 HCP in Standard American or 20-22 HCP in standard Acol, and for even stronger balanced hands, the opening bid of 2♣ can be used. The opener's rebid (in these cases always in No Trump) then indicates the strength of the hand using steps of 2-3 HCP. Hence 2♣ - 2♦ - 2NT shows 22-24 HCP's in Standard American or 23-24 HCP in Acol, while a 3NT rebid can show 25+ HCP's.
If the opening bid of 2♣ is exclusively used for strong hands, the auction becomes more susceptive to disruptive (jump) overcalls (especially when the opposing partnership is not vulnerable) than the "old" treatment of strong two bids. However, that danger is smaller when compared to strong 1♣ system in strong club systems, because 2♣ bid is made with bigger high-card strength and on a higher level. On the other hand, the strong 2♣ opening reduces the bidding space for the pair themselves compared with strong 1♣—sometimes, the pair can be unable to find a fit on a relatively low level (below 3NT), and/or reduce the space for effective slam investigation with cue bidding.
In most strong club systems, the opening bid of 2♣ is natural and promises a hand with long clubs (for example, in both Precision and Blue club, it shows 11-15 high card points and either a 6-card club suit or at least a 5-card club suit and a 4-card major suit). As such, it makes overcalls more difficult, since they have to be made at the two-level. Chances are therefore increased that the side of the opener has an undisturbed auction, and the opponents will not discover a fit in a major suit. However, as a corollary, their strong 1♣ opening bid is more susceptible to preempting by opponents.
Another variant advocates two strong forcing openings, 2♣ for strong hands with fewer than four spades and 2♦ for strong hands with four or more spades. [5]
Stayman is a bidding convention in the card game contract bridge. It is used by a partnership to find a 4-4 or 5-3 trump fit in a major suit after making a one notrump (1NT) opening bid and it has been adapted for use after a 2NT opening, a 1NT overcall, and many other natural notrump bids.
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.
Acol is the bridge bidding system that, according to The Official Encyclopedia of Bridge, is "standard in British tournament play and widely used in other parts of the world". It is a natural system using four-card majors and, most commonly, a weak no trump.
Polish Club is a bridge bidding system which was developed in Poland, where it is the most popular bidding system, and which is also used by players of other countries. It is a type of small club system.
A game try in the card game of bridge is a bid that shows interest in bidding a game and asks partner to help in making the decision.
The forcing notrump is a bidding convention in the card game of bridge.
The Jacoby transfer, or simply transfers, in the card game contract bridge, is a convention in most bridge bidding systems initiated by responder following partner's notrump opening bid that forces opener to rebid in the suit ranked just above that bid by responder. For example, a response in diamonds forces a rebid in hearts and a response in hearts forces a rebid in spades. Transfers are used to show a weak hand with a long major suit, and to ensure that opener declare the hand if the final contract is in the suit transferred to, preventing the opponents from seeing the cards of the stronger hand.
Zar Points (ZP) is a statistically derived method for evaluating contract bridge hands developed by Zar Petkov. The statistical research Petkov conducted in the areas of hand evaluation and bidding is useful to bridge players, regardless of their bidding or hand evaluation system. The research showed that the Milton Work point count method, even when adjusted for distribution, is not sufficiently accurate in evaluating all hands. As a result, players often make incorrect or sub-optimal bids. Zar Points are designed to take many additional factors into consideration by assigning points to each factor based on statistical weight. While most of these factors are already implicitly taken into account by experienced players, Zar Points provides a quantitative method that allows them to be incorporated into bidding.
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 with a long suit. It is used in combination with the strong two clubs bid and is a form of preemptive bid. The term refers to an opening bid, and is not to be confused with the "weak jump overcall", which denotes a similar type of hand, but is bid over an opponent's opening bid.
Jacoby 2NT is a bridge convention in which a bid of 2NT over partner's opening bid of one heart or one spade shows a hand with both
Multi coloured 2 diamonds, or simply Multi, is a contract bridge convention whereby the opening bid of 2♦ shows several possible types of hands. These always include a weak-two bid in either major suit; the additional meaning may be a strong balanced hand, or a 20-22 three suiter. The inherent ambiguity as to both suit and strength makes it a powerful and popular convention capable of seriously disrupting the opponents' bidding.
In natural bidding systems most notrump (NT) bids are made with balanced hands and within a narrowly defined high card point (HCP) range. In these systems, such as Acol and Standard American, NT bids are limit bids and therefore are not forcing. Bearing in mind the need to bid only to the optimum contract and no higher, bids above game are made only in specific circumstances, one of which is to alert partner to the fact that a slam may be possible and inviting partner to take part in the decision making process.
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 overcall.
The Kaplan–Sheinwold bidding system was developed and popularized by Edgar Kaplan and Alfred Sheinwold during their partnership, which flourished during the 1950s and 1960s. K-S is one of many natural systems. The system was definitively described in their 1958 book How to Play Winning Bridge and later revised and retitled to The Kaplan-Sheinwold System of Winning Bridge in 1963.
A reverse, in the card game contract bridge, is a bidding sequence designed to show additional strength without the need to make a jump bid; specifically two suits are bid in the reverse order to that expected by the basic bidding system. Precise methods and definitions vary with country, bidding system and partnership agreements.
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:
Bridge base basic, also known as BBO basic, is a bidding system for the game of bridge based on the Standard American Yellow Card (SAYC). It is simplified, suitable for beginners, and widely used in internet bridge, particularly on Bridge Base Online. It is taught in Fred Gitelman's educational software called Learn to Play Bridge that is available as a free download from the American Contract Bridge League's website.
Transfer Walsh is a bidding convention used in contract bridge. After a 1♣ opening bid, responses of 1♦ and 1♥ show heart and spade suits respectively. The "Walsh" terminology refers to the fact that these bids may conceal an equal or longer diamond suit. It allows opener to play a greater proportion of major-suit and no-trump contracts, particularly when using five-card majors.