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:
- 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 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As slam bidding conventions at or near the 4NT level, San Francisco and Norman four notrump have been superseded by the Blackwood convention and its variants, which show at once only the number of aces or keycards, and show kings subsequently if at all.
Famous quotes containing the words san francisco, san, francisco and/or convention:
“Mining today is an affair of mathematics, of finance, of the latest in engineering skill. Cautious men behind polished desks in San Francisco figure out in advance the amount of metal to a cubic yard, the number of yards washed a day, the cost of each operation. They have no need of grubstakes.”
—Merle Colby, U.S. public relief program (1935-1943)
“The gold-digger in the ravines of the mountains is as much a gambler as his fellow in the saloons of San Francisco. What difference does it make whether you shake dirt or shake dice? If you win, society is the loser.”
—Henry David Thoreau (1817–1862)
“Today, San Francisco has experienced a double tragedy of incredible proportions. As acting mayor, I order an immediate state of mourning in our city. The city and county of San Francisco must and will pull itself together at this time. We will carry on as best as we possibly can.... I think we all have to share the same sense of shame and the same sense of outrage.”
—Dianne Feinstein (b. 1933)
“By convention there is color, by convention sweetness, by
convention bitterness, but in reality there are atoms and space.”
—Democritus (c. 460–400 B.C.)