Responses A. 2C - Puppet Stayman. Used with either a diamond signoff, interest in a major, or some type of invitational hand. B. 2D - Relay Stayman. Forcing to game. Either preemptive in next higher suit or void in that suit.
Responder is weak.
I. 4H, 4S, 5C, 5D - to play, says it is our hand. Responder signs off by bidding 2NT, 3C, or 3D and invites game with 3H or 3S. B. 2D by opener denies a 5-card major. 2M are to play. This creates a game force and is artificial. It begins a series of relay bids by responder to discover opener's distribution and high card placement.