A Multi Two Diamonds is a bid which is used to describe a number of possible hands
The Multi Two Diamonds bid is defined in the EBU Orange book as-:
"Must contain a weak option and one or two strong options."
Weak Options.
A weak two-bid in Hearts or Spades, defined as no more than a 5 point range between 4pts and 12pts and containing 5+ cards.
A weak two-bid in Hearts only but not in Spades only
Strong Options.
Any 4-4-4-1 shape with defined point range.
A balanced hand of defined point range
An Acol Strong Two in any suit provided in has a least 14 points and complies with the Rule of 25
Any Game Forcing Hand
So your decision!
You can play it as a weak two in a Major and one or two of the strong options
If their is no
interference the standard responses are ;
2 ♥ - usual meaning is " if your hand is a weak two
in Hearts I don't want to proceed any further.
2 ♠- usual meaning is " if your hand is a weak two in Spades
I don't want to proceed any further, but I can compete up
to 3 ♥
2NT Ask opener to describe their hand and normally means
that the Responder is interested in Game somewhere.
After any of these responses the bids will vary considerably
depending on which options you are playing.
You have to work them
out for yourself. Not only the straightforward ones but after interference.
If you want to play this convention- beware
Most tournament players can cope with it using planned defensive bidding methods
and will cause you problems by interfering as much as possible.
For example, you are South.
North opens 2 ♦, which you alert, and explain, if asked
East bids anything- 2 ♥ 2 ♠
3 ♣ 3 ♦ Double, 2NT etc
Your bids can be Double, Redouble, 2NT, and any suit at the 3 or 4 level
So if you bid (or Pass) your partner must know what you are saying
So put together you own system, if you have a regular partnership, and feel it
could be useful but be very careful.