One, if by land, and two, if by sea" was the agreed signal, you remember. But do you recall how many lanterns Paul Revere's friend hung in the tower of the Old North Church? Of course, you could work it out for yourself if you happen to know that on the 18th of April in '75 the British sailed out of Boston.
Which leads, via no rude bridge, to the point that you are entitled to know what signals your opponents are using. If you are observant, sometimes you can get just as much information as the signaler's partner. In fact, a signal may be more helpful to you, the declarer.
This deal, played in a team match of international stars vs. Omar Sharif's Bridge Circus is a case in point. At one table a signal in clubs helped declarer make the contract; at the other table, not using the same card signal led to defeat of the contract.
Sharif ducked the first club and Sam Stayman won with the king, returning the 8 of clubs—the higher of his remaining cards in the suit—to indicate that his reentry was in the higher of the remaining side suits. Thus, when the second club was won in dummy and the 10 of hearts was returned, Vic Mitchell won with the queen and returned a spade. Of course, East's signal in clubs might have been a doublecross, but such plays rarely are, because it is usually more important to guide partner than to try to fool declarer. At any rate, Sharif took East's signal as honest. He considered only briefly letting the lead ride to his queen of spades. Instead, he rose with dummy's ace, crossed to the king of diamonds and returned a diamond, finessing dummy's jack. When the finesse won, declarer's queen of spades was pitched on the ace of diamonds. Now when trumps were led West made his ace but couldn't put partner in. The club ruff evaporated and the contract was made.
Mitchell speculated on what would have happened if he had won the first trump lead with the ace instead of the queen and, like all the really top stars, he blamed himself for not having made the play. On the ensuing spade shift, South would naturally assume that the finesse for the heart queen was working. Figuring that he could afford a spade loser as long as he lost only one trump trick, he would rise with the ace of spades and let the 9 of hearts ride. But West would grab the queen, put East in with the spade king and get a club ruff, for down two.
What happened at the other table was equally diabolical. Giorgio Belladonna chose the same club lead against Howard Schenken's contract. Schenken played dummy's queen and—well, let Peter Leventritt, North, tell it.
"That Benito Garozzo can find more ways to beat you. Without the slightest hesitation he played the 4 of clubs, letting the queen hold the trick! Howard finessed the 10 of hearts, losing to the queen, and Belladonna continued clubs. Howard was on the spot. He looked suspiciously at Benito, but he had to assume West had the king of clubs. If East's initial play of the 4 was a singleton, going up with the ace might be the only way to lose the contract.
"So Howard finessed, lost to the king of clubs and saw Benito give his partner a club ruff. With the ace of trumps out, the contract was surely set. When West next returned a spade, taking the diamond finesse to try to avoid a spade loser risked going down three, so Howard let the spade ride, lost to the king and wound up minus 200."