Multi-coloured 2 diamonds, is a contract bridge convention whereby the opening bid of 2D shows a defined range of hand types. These always include a weak-two bid in a major suit, and the second option, that must be a strong. The inherent ambiguity as to both suit and strength makes a powerful, and hence popular. It was originally considered disruptive, but is now thought fairly easy to defend. It is commonplace in the British Isles, permitted in international competition, but rarely seen North America.
The convention offers several constructive system opportunities. You might choose that its weak option always be a standard 6-card Major, and then use 2H and 2S as e.g. the Muiderberg/Lucas Two two-suited weak openings.
The strong options are also important as they may be used "garage” hand types that are otherwise awkward within your general system. Some English pairs include 2NT with 5-card major or 6-card minor. This avoids need for puppet Stayman, greatly streamlining assessment of slam prospects over a simplified 2NT opening.
While technically a "brown sticker" convention because Multi has known "anchor suit", its popularity, and availability of published defenses, have persuaded the World Bridge Federation to allow its use even in lower rankings tournaments. It is described in the WBF Convention Booklet. It is permitted by the English Bridge Union at competition Level 4.
You may not describe 2D as "Multi" unless it is ambiguous as with respect to its weak major option
An opening bid of 2D - which must contain both a weak AND a strong option.
The weak option must be either 5+ ambiguous major (any style) or "always hearts" ("Always spades" not permitted)
The strong option must be 1 or 2 (no more) choices taken from:
You are not permitted to pass 2D.
The initial response should assume that opener has a weak two in a major. It is standard to offer a Paradox method advance. That is to say that 2H is pass/correct. A call of 2S "paradoxically" indicates that you are willing to play in hearts, be that in a 3H or 4H contract. You have bid the suit that you don't support!
A common agreement is that calls of 3H and above "extend the pre-empt". Paradox methods are again applied; 3S implies that you are willing to play in 4H. You should decide whether direct call of 4H major is to play, or pass/correct!
It is important to discuss this with your partner. A simple agreement over double is to simply make the same Paradox advance that you would have done anyway. You should agree whether pass, or redouble show willingness to play in diamonds. Always bear in mind that fourth hand will usually make a bid, and you will always get a second opportunity to bid or double.
A common agreement is that 3H or 4H over a minor overcall are pass/correct.
Overcalls in a major suit is more awkward to handle, but a common agreement is that opener must double or bid should he hold the strong option, clarifying type if you have 2 of those.
There are numerous popular defenses to the Multi. The "Dixon" method below is not necessarily best from a technical point of view, however it is perfectly adequate and is easy to remember. In general, when defending against a multi players should assume that the opener holds one of the weak options. They occur much more frequently than the strong ones!
With a good suit, it is important to bid aggressively on the first round of bidding, before opener's partner has disambiguated the opening. Otherwise, it is often wise to wait until it is apparent what opener's suit is. In this mode 2nd hand passes initially, A takeout double of the Pass or correct response then becomes your key weapon on round 2 of bidding.
It is helpful to discuss the concept of "position"(i.e. relative to opener) with your partner, in any defence agreement.
2 Clubs may also be used as a Multi opening. It is most commonly seen in conjunction with Benjaminised Acol, where a 2D opening is strong. 2C strong options might be either the game forcing, or Acol Two hand types.
Depending on regulations, weak option is usually ambiguous with respect to major, but you may be allowed to include a weak, 5+ diamonds type in addition.
Tartan Two bids allow multi-like openings in 2H or 2S, showing either a Strong Two in the suit, a weak 2-suiter including that suit, or (optionally) strong balanced. In essence they combine Acol Two's with a Lucas Two. A significant disadvantage is that you cannot stop at the 2 level with the weak hand type.
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 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 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 long suit, usually a major, 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.
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.
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.
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
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 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 or protective overcall.
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.
The Carrot 1NT is a contract bridge convention, in which a 1NT opening bid shows a balanced hand 13–17 HCP. With 13–14 HCP, the opener may not have a 4-card major. With 15–17 HCP, all balanced hands may be opened 1NT.
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.
Antispades Twos is the name of a bidding convention in the card game bridge. It is a two-level pre-emptive opening based on either a 6-card suit or a two-suiter with at least nine cards distributed across any two suits.