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 "bridge-whist", became popular in the United States and the United Kingdom in the 1890s despite the long-established dominance of whist. In 1904 auction bridge was developed, in which the players bid in a competitive auction to decide the contract and declarer. The object became to make at least as many tricks as were contracted for, and penalties were introduced for failing to do so. Auction bridge bidding beyond winning the auction is pointless. If taking all 13 tricks, there is no difference in score between a 1 and a 7 final bid, as no bonus for game, small slam or