In recent years the Multi-2♦ Opening bid has become very popular and widespread in Duplicate bridge competition.
This bid replaces the regular weak . . . . . , . . . . . . . . and . . . . . . . . opening bids as outline in this course in Lesson 16.
The Game force 2♣ Opening (also introduced in Lesson 16) remains in use however.

Even if you do not intend to use these bids it is useful to have a general knowledge of their meaning as they are used by many intermediate and better players you might find yourself playing against.

The Multi-2♦ combines a number of possibilities into the one Opening bid. There are a range of combinations used. I have selected one popular version here, which also fits in well with the overall System outlined here by Jazclass.

The Multi-2♦ Opening covers the following hand options :

The Multi-2♦ therefore telescopes the weak 2s for . . . . . . into one bid.
It also includes the balanced . . . . . point hand which is too . . . . . for a 1 Opening bid, but too . . . . for a 2♣ Game force.
The third option includes the strong . . . . . . hands without a . . . card suit (. . . . . . ), just under or within the . . . . . . . . opening bid range.

This makes the bids of 2♥, 2♠ and 2NT* available for other purposes which will outlined in the next Lesson.

There are two weak responses to the Multi-2♦ Opening bid. They are

• 2♦ - . . . . . = "Pass or correct"

• 2♦ - . . . . . . . = "I have no interest in . . . . , but if you have . . . . . instead I might be interested in Game."

Opener's replies are as follow.

After a 2♠ response Opener's replies are the same as above, except when Opener holds a weak 6+card . . . . suit.
In that case Opener replies 3♥ with a . . . . . (. .. HCP) and 4♥ with a . . . . . . . (. . . . . HCP).

The 2NT response after a 2♦ opening bid shows 12+ HCPs, is artificial and a strong enquiry similar in nature to the Ogust Convention. There are several possibilities for weak major suit responses. Here follows my recommended version.

After Opener's weak reply of 3♥ or 3♠, the Responder usually . . . . . . .
After Opener's positive reply of 3♣ or 3♦, a . . . . . . . is usually reached.

A further bid by Responder . . . . . from Opener's previous bid asks for the number of top Honours (A, K or Q) in Opener's long suit.

For example :

With one of the strong option hands, Opener's reply to Responder's 2NT strong enquiry are very simple :

After this the bidding usually reaches a Slam contract.

Interference over a multi-2♦ Opening bid is not uncommon in cases where Opener's bid is based on a weak long major suit. The following standard actions over this are outlined below.

A. After Opponents Double

1. Pass = . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2. Bid a suit = . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3. Bid 2NT = . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4. DBL = . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1. Pass = . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2. Bid a suit = . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3. DBL = . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4. Cue bid Enemy suit = . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1. DBL = . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2. 3♥ = . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3. 3♠ = . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .