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
Contract bridge the round; otherwise, they receive penalty points. Bridge extends the concept of bidding into an , where partnerships compete to take a , specifying how many tricks they will need to take in order to receive points, and also specifying the trump suit (or no trump, meaning that there will be no trump suit). Players take turns to call in a clockwise order: each player in turn either passes, doubles—which increases the penalties for not making the contract specified by the opposing partnership's last bid, but also increases the reward for making it—or redoubles, or states a contract that their