(Mostly from Aaron Mohrman and Jeff Ford.)
In order to clarify 2/1 auctions, we like for most bids by opener and by responder to be natural. Therefore, we overload the 2C response (alertable): Game Force, either balanced or with clubs.
After 1S – 2C the structure is as follows:
- 2D – Artificial waiting bid showing a nondescript opener. Then:
- 2H – A real 5-card club suit. (This is not natural: responder has denied 5 hearts and opener has denied 4 hearts so we cannot have a fit.)
- 2S – Primary spade support. This initiates a standard 2/1 auction when a fit has been discovered.
- 2NT – A balanced hand oriented towards playing no-trump. (Less than 3 spades.)
- 3C – A club suit I would have bid and rebid in a standard 2/1 auction. This usually shows at least six clubs.
- 2H – 4+ hearts
- 2S – 6+ spades
- 2NT – A hand well oriented to playing no-trump
- 3C – A high reverse an independent club suit and extra strength or distribution. It is not a raise, because responder may not have a real club suit (could be as short as 2).
After 1H – 2C the structure is as follows:
- 2D – Artificial waiting bid showing a nondescript opener. Then:
- 2H – Primary heart support. This initiates a standard 2/1 auction when a fit has been discovered.
- 2S – A real 5-card club suit. (This is not natural: responder has denied 5 spades and opener has denied 4 spades so we cannot have a fit.)
- 2NT – A balanced hand oriented towards playing no-trump. (Less than 3 hearts.)
- 3C – A club suit I would have bid and rebid in a standard 2/1 auction. This usually shows at least six clubs.
- 2H – 6+ hearts
- 2S – 5+ hearts and 4+ spades
- 2NT – A hand well oriented to playing no-trump
- 3C – A high reverse showing opener has an independent club suit and extra strength or distribution. It is not a raise, because responder may not have a real club suit (could be as short as 2).
Wtih a 5-card red suit, Responder should show that instead of bidding 2C. Over 1M-2D or 1S-2H, opener’s rebid of 2M is waiting and doesn’t promise extra length.
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