Grand slam force
Encyclopedia
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 (notrump), when it does not conflict with other conventions used by that partnership (e.g., a 5NT Blackwood
bid), is forcing to slam in the suit last bid, unless the trump suit has already been agreed on earlier in the auction. The partner of the 5NT bidder bids as follows:
For example, if a partnership is using the Grand Slam Force and one member bids 1♥ and his or her partner bids 5NT, it is implied that hearts are the desired trump suit. The original bidder will sign off with 6♥ with one of the top three heart honors, and bid 7♥ with two of the top three heart honors.
As with all bidding systems, the Grand Slam Force has its limitations, not the least of which is that the chances of employing it directly over an opening one-bid are extremely rare and 5NT must be understood to be the GSF in other situations. Also, numerous variations on this convention have been developed.
Slam-seeking conventions
Slam-seeking conventions are codified artificial bids used in the card game contract bridge. Bidding and making a small slam or grand slam yields high bonuses ranging from 500 to 1500 points. However, the risk is also high as failure to fulfill the slam contract also means failure to score the...
in contract bridge
Contract bridge
Contract bridge, usually known simply as bridge, is a trick-taking card game using a standard deck of 52 playing cards played by four players in two competing partnerships with partners sitting opposite each other around a small table...
that was developed by Ely Culbertson
Ely Culbertson
Ely Culbertson was an entreprenurial American contract bridge personality dominant during the Thirties and Forties. He played a major role in the early popularization of the game, and was widely regarded as "the man who made contract bridge"...
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 (notrump), when it does not conflict with other conventions used by that partnership (e.g., a 5NT Blackwood
Blackwood convention
In the partnership card game contract bridge, the Blackwood convention is a popular bidding convention that was developed by Easley Blackwood. It is used to explore the partnership's possession of aces, kings and in some variants, the queen of trumps, to judge more precisely whether slam is likely...
bid), is forcing to slam in the suit last bid, unless the trump suit has already been agreed on earlier in the auction. The partner of the 5NT bidder bids as follows:
- 6 of the agreed trump suit if holding one of the top three trump honors (e.g., the ace)
- 7 of the agreed trump suit if holding two of the top three trump honors (e.g., the king and queen)
For example, if a partnership is using the Grand Slam Force and one member bids 1♥ and his or her partner bids 5NT, it is implied that hearts are the desired trump suit. The original bidder will sign off with 6♥ with one of the top three heart honors, and bid 7♥ with two of the top three heart honors.
As with all bidding systems, the Grand Slam Force has its limitations, not the least of which is that the chances of employing it directly over an opening one-bid are extremely rare and 5NT must be understood to be the GSF in other situations. Also, numerous variations on this convention have been developed.
See also
- Blackwood conventionBlackwood conventionIn the partnership card game contract bridge, the Blackwood convention is a popular bidding convention that was developed by Easley Blackwood. It is used to explore the partnership's possession of aces, kings and in some variants, the queen of trumps, to judge more precisely whether slam is likely...
- Norman four notrumpNorman four notrumpNorman four notrump is a slam bidding convention in the partnership card game contract bridge designed to help the partnership choose among the five-, six-, and seven-levels for the final contract...
- Quantitative notrump bids
- Slam-seeking conventionsSlam-seeking conventionsSlam-seeking conventions are codified artificial bids used in the card game contract bridge. Bidding and making a small slam or grand slam yields high bonuses ranging from 500 to 1500 points. However, the risk is also high as failure to fulfill the slam contract also means failure to score the...
- Cue bidCue bidIn contract bridge, a cue bid is a term that applies to two types of bid:*A bid of a suit that has already been bid by opponents.*A slam-investigating bid made during an auction's later rounds that shows control of a suit...