San Francisco convention
Encyclopedia
In the partnership card game
contract bridge
, the San Francisco convention is a slam bidding convention, or a special usage by partnership agreement in order to help choose among the five, six, and seven levels for the final contract. One partner bids 4NT to ask, and the other replies, in code, to show aces and kings in one bid. Thus it is an alternative to the Blackwood convention
family.
The San Francisco reply is usually sufficient for partner to infer the precise numbers of aces and kings in the replying hand, hence in the two partnership hands. So it is useful where partner can choose the contract level by knowing the numbers of aces and kings that are "missing" in the two opposing hands.
The San Francisco scale is three points for an ace, one for a king. The asking bid is 4NT with these replies:
Except for 5=0–2, 5=5, and 6=8, the replies are equivocal with reference to the entire 52-card pack, but the other replies may be unequivocal given reference to another hand, typically partner's hand. For example, if partner holds two kings then 5NT must be two aces.
The San Francisco replies take so much space
that a weak or medium-strength hand may need to investigate slam by other methods.
As slam bidding conventions
at or near the 4NT level, San Francisco and Norman four notrump
have been superseded by the Blackwood convention
and its variants, which show at once only the number of aces or keycards, and show kings subsequently if at all.
Card game
A card game is any game using playing cards as the primary device with which the game is played, be they traditional or game-specific. Countless card games exist, including families of related games...
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...
, the San Francisco convention is a slam bidding convention, or a special usage by partnership agreement in order to help choose among the five, six, and seven levels for the final contract. One partner bids 4NT to ask, and the other replies, in code, to show aces and kings in one bid. Thus it is an alternative to the Blackwood convention
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...
family.
The San Francisco reply is usually sufficient for partner to infer the precise numbers of aces and kings in the replying hand, hence in the two partnership hands. So it is useful where partner can choose the contract level by knowing the numbers of aces and kings that are "missing" in the two opposing hands.
The San Francisco scale is three points for an ace, one for a king. The asking bid is 4NT with these replies:
- 5 : 0 to 2 points, i.e. 0 to 2 kings only
- 5 : 3 points
- 5 : 4 points
- 5 : 5 points
- 5NT : 6 points, i.e. two aces or one ace and three kings
- etc.
Except for 5=0–2, 5=5, and 6=8, the replies are equivocal with reference to the entire 52-card pack, but the other replies may be unequivocal given reference to another hand, typically partner's hand. For example, if partner holds two kings then 5NT must be two aces.
The San Francisco replies take so much space
Useful space principle
The Useful Space Principle, or USP, was first articulated in a series of six articles in The Bridge World, from November 1980 through April 1981...
that a weak or medium-strength hand may need to investigate slam by other methods.
As slam bidding conventions
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...
at or near the 4NT level, San Francisco and Norman four notrump
Norman four notrump
Norman 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...
have been superseded by the Blackwood convention
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...
and its variants, which show at once only the number of aces or keycards, and show kings subsequently if at all.