Grand slam force Grand slam force The Grand Slam Force is a bidding convention in contract bridge that was developed by Ely Culbertson in 1936. It is intended to be used in cases where the combined hands of a partnership are so strong that a slam (winning at least 12 tricks) is a near-certainty and a grand slam (winning all 13 tricks) is a possibility. It allows one partner to gain information on the quality of trumps in the other partner's hand. When this convention is in force, a bid of 5NT (five notrump), when it does not conflict with other conventions used
Bidding system suit. Natural systems generally use opening bids as follows: The most widespread natural systems are: Various developments in the area of natural systems have resulted in systems that are natural in essence, but contain special features. Examples are systems like Romex, Boring Club, Fantunes, and EHAA (Every Hand An Adventure). Artificial systems can be further classified into: Bidding system A bidding system in contract bridge is the set of agreements and understandings assigned to calls and sequences of calls used by a partnership, and includes a full description of the meaning of each treatment and convention. The purpose of bidding