An opening 2D shows one of three types of hands
(i) Weak two in a major suit
(ii) A strong balanced hand of a defined range (about 21-22 HCP balanced)
(iii) Strong three-suited hand. (4441 or 4450 shape and about 18-21 HCP)
Responses to 2D. The first response assumes that Opener has a weak two
in a major. Opener may use these responses with a stronger hand to determine the best contract
2H: Willingness to play here opposite weak heart bid
2S: Willingness to play here, but also interested in hearts (obviously, has support for both)
2N: Forcing, asking opener to clarify his hand.
3C natural, 6+ card suit, constructive and non-forcing
3D natural, 6+ card suit, constructive and non-forcing
3H Preemptive in whichever major opener holds, if opener has a weak 2 bid
3NT to play, usually based on a long minor suit
4C natural and game-forcing
4D natural and game-forcing
4H to play in partner's major (must have support for both, of course)
4S to play
If responder is only interested in playing 4H, respond 2H, then bid 4H after partner's expected 2S rebid
Opener's rebids. With type (i):
Over 2H: pass or bid 2S
Over 2S: pass or bid 3H
Over 2N: bid 3C to show hearts, upper range; 3D to show spades, upper
range; 3H or 3S with lower range.
With type (ii) hand: rebid in notrumps at the minimum level.
Other rebids show type (iii) and should be specified on the convention card.