ACES ON BRIDGE
“Habitual liars invent falsehoods not to gain any end or even to deceive their hearers, but to amuse themselves. It is partly practice and partly habit. It requires an effort in them to speak truth.”
— William Hazlitt
The art of deceptive defense comes in many forms. Sometimes you need to misrepresent your hand to your partner to get him to make the right play.
However, it may be even more satisfying to trick declarer into doing the wrong thing. Sometimes you can signal deceptive attitude about an honor in a critical suit. Similarly, you may try to persuade declarer that you are threatening a ruff or overruff, or give false count to make declarer think a suit is breaking when it is not.
As East, after South opens one spade and your partner overcalls two hearts, you defend against four spades. When your partner leads a top heart, your best play is to signal a high-low in hearts to simulate a doubleton. If your partner leads three rounds of the suit, do you think declarer will be able to bring himself to ruff low? If he ruffs with the king, jack or 10, then you will have a trump trick and a club to come.
How would declarer play if you told the truth in hearts? Imagine that after your partner leads three rounds of hearts, declarer ruffs the third one low. His best play is then to cash the spade king and take three rounds of diamonds, finishing in dummy. Assuming they stand up, declarer discards a club from hand, then passes the spade jack. This line succeeds as long as West started with a singleton spade or the doubleton queen and two or three diamonds, since either the finesse will win or West will be endplayed.
ANSWER: Had your LHO raised clubs, you would have doubled for takeout; and had he bid one spade, you might have been tempted to try one no-trump. Indeed, you still might quite reasonably do that. But you also have the option as a passed hand to redouble to show values, which also tends to suggest something like a doubleton in support of partner. With more trumps, you would raise directly.