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 a prolific author of bridge books, points out that there are only four ways of taking a trick by force, two of which are very easy: Nearly all trick-taking techniques in bridge can be reduced to one of these four methods. The optimum play of the cards can require much thought and experience and is the subject of whole books on bridge. The cards are dealt as shown in the bridge hand diagram; North is the dealer and starts the auction which proceeds as shown in the bidding table. As neither North nor East have sufficient strength to "open" the