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 box Bidding box A bidding box is a device used for bidding in bridge, usually in duplicate bridge competitions. Made in various configurations and sizes, it is typically a plastic box with two holding slots, each containing a set of bidding cards: one with 35 cards with symbols of bids, and the other with cards for other calls (pass, double, etc.). Invented in Sweden in 1962, they were first used at a World Bridge Championships game in 1970. Their usage eventually spread in Europe, United States and across the world, and today they present a virtually indispensable piece of equipment even