Multi is an opening cpnvention to show weak 2 either in spade or heart. Many also like to include a strong NT(20-21 / 22-24) in the conventions but that is optional. 


RESPONSES TO 2D OPENING:

• 2H: Not game if Weak 2 Hearts.

• 2S: Invitational if Hearts.

• 2NT: Forcing.

• 3C: Natural and forcing.

• 3D: Natural and forcing.

• 3H: Preempt in weak 2 suit.

• 3NT: To play.

REBIDS AFTER 2D - 2H:

• Pass: Weak 2 Hearts.

• 2S: Weak 2 Spades.

• 2NT: Strong NT. (Optional)

REBIDS AFTER 2D - 2S:

• Pass: Weak 2 in spades.

• 2NT: Strong NT.  (Optional)

• 3H: Weak 2 in hearts and minimum.

• 4H: Weak 2 in hearts and maximum.

REBIDS AFTER 2D - 2NT:

• 3C: Weak 2 Hearts. Minimum.

• 3D: Weak 2 Spades. Minimum.

• 3H: Weak 2 Hearts. Maximum. --> New suit Cue-Bid.

• 3S: Weak 2 Spades. Maximum. --> New suit Cue-Bid.

• 3NT: Strong NT. (Optional)