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 goal of bridge is not simply to take the most tricks in a deal. Instead, the goal is to successfully estimate how many tricks one's partnership can take. To illustrate this, the simpler partnership trick-taking game of Spades has a similar mechanism: the usual trick-taking rules apply with the trump suit being spades, but in the beginning of the game, players "bid" or estimate how many tricks they can win, and the number of tricks bid by both players in a partnership are added. If a partnership takes at least that many number of tricks, they receive points for