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 eg 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 Description 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: An Acol Two, the suit need not be specified A strong 3-suited hand, the singleton need not be specified A strong balanced or semi balanced hand (±singleton) Any game forcing of hand type or types Continuation 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