Multi two diamonds

Multi-coloured 2 diamonds, is a contract bridge convention whereby the opening bid of 2♦ 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 in North America.

The convention offers several constructive system opportunities. It might be decided that its weak option always be a standard 6-card Major, and then that 2♥ and 2♠ are used as e.g. the Muiderberg/Lucas Two two-suited weak openings.

The strong options are also important as they may be used for 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 no 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. 2♦ is not "Multi" if it is not ambiguous with respect to its weak major option