http://home.mn.rr.co...ed_reverses.htm
For this discussion, a reverse is defined as when opener's second bid is a non-jump 2-level bid of a higher-ranking suit after responder has made a 1-level bid. A reverse by opener shows 17+ points and insufficient values to bid two clubs. Structured reverses are used to help opener decide what level to set the contract. A reverse is absolutely forcing for one round, and in some cases more, but is not absolutely forcing to game.
Responder's obligation is to show the strength of his hand on the next bid. With a "weak" hand, in this case, defined as less than 9 points, he has only two options: if he holds a 5-card or longer major suit that he can bid at the two-level, he bids it; lacking a 5-card major, or if he would be forced to bid his major at the three-level, he can show weakness by bidding two no-trump. Any other bid shows 9+ points. Responder's second bid is also forcing. After showing a weakness signal, responder may later show support for one of opener's suits.
Sequences that are non-forcing when responder has shown weakness:
Opener bids 2NT
1C 1S
2H 2S
2NT (allowed to pass, but may bid 3C, 3D, 3H, 3S, or 3NT--in each case the meaning is obvious)
Opener re-bids his first suit
1C 1S
2D 2NT
3C (allowed to pass, but may bid 3C, 3D, 3H, or 3NT, spades is out as responder has already denied holding 5+ spades)
Opener raises responder's suit, but not to game
1C 1S
2H 2S
3S (allowed to pass, or may bid 4C, 4H, or 4S)
Opener bids 3NT
1C 1S
2H 2S
3NT (allowed to pass, opener wants to play in game regardless)
Despite responder's weakness signals above, there will be times when he will still either invite or raise to game. Responder can have a hand that wants to play in game opposite opener's hand, but want to first discourage opener from considering slam.
Forcing sequences where responder has shown weakness
Opener bids the fourth suit
1C 1S
2H 2S
3D (responder cannot pass, if the fourth suit is a minor, it should be a legit 5-4-4 hand, if a major, the fourth suit is suspect)
Opener re-bids his SECOND suit
1C 1S
2H 2S
3H (opener is showing 6 clubs and 5 hearts or better, responder cannot pass)
Opener jumps in his first bid suit
1C 1S
2D 2NT
4C (opener shows a 6+ card club suit and responder cannot pass)
Opener supports responder's non-five-card suit (I question this a bit)
1C 1S
2H 2NT
3S (responder cannot pass, and opener is showing 3-card support)
Strong Auctions
Responder supports either of opener's suits, there is no need to jump, game-force and slam is possible
1C 1S
2H 3C
or
1C 1S
2H 3H
Responder bids 3NT, suggests to play here, but is neither forcing nor drop-dead. Responder holds about 10-12 HCP's.
1C 1S
2H 3NT
Responder jumps in his own suit, this shows a good 6+ card suit and is forcing to game
1C 1H
2D 3H
Auctions where responder bids 1NT. To show weakness, responder's only options are to bid 2NT or support opener's first bid suit.
1D 1NT
2H 2NT (this shows weakness and opener can pass)
1D 1NT
2H 3D (this shows weakness and opener can pass)
1D 1NT
2H 3H (forcing to game, shows exactly 3 good hearts)
1D 1NT
2H 3C (shows a real club suit and is forcing to game)
1D 1NT
2H 3NT (opener can pass, un-bid suits will be stopped, 10-11 HCP's)
1D 1NT
2H 2S (since you denied spades with your first bid, shows a spade stopper with 3 spades and looking for 3NT)
1H 1NT
2S 3H (this topic is open for discussion. obviously forcing to game, but is this weaker or stronger than the auction in 8)
1H 1NT
2S 4H (using the principle of rapid arrival, this should likely be the weaker hand, but see question in sequence 7)