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
Optimum contract and par contract value of the bonuses (especially when vulnerable). In duplicate pairs scoring, the subtle difference between a major suit game, a NT game and a minor suit game make the declaration an important decision. Each side has its own optimum contract and, for a side with poor hands, "pass" may be the optimum call. Where there is competitive bidding (i.e. both sides are bidding) the extra dimension of sacrificial bidding is added, and the theoretical optimum contract can be overtaken by the par contract. The par contract on a deal is that contract that results from optimal bidding by both sides