Bridge by Frank Stewart
"I'm not prone to hyperbole," a club player told me, "but my wife really is one in a million. We were on a road trip, and she told me not to bother to stop and ask for directions. She said I'd figure out how to get where we were going."
My friend was today's West, and when North-South got to 3NT, he led a diamond. South won with the nine and forced out the ace of clubs. When East shifted to the king of hearts, South played low, won the next heart, and led the king of diamonds. West took his ace, and South took the rest, making an overtrick.
"Maybe your wife should have given you some directions," I told West mildly. "Your opponents had a slow auction to game; they had no extra strength. If your wife doubles 3NT to ask for a heart opening lead, you'll get three heart tricks and two aces."
"Well, you can't have everything," West shrugged. "She's also a magnificent cook."
Every player should be familiar with lead-directing doubles. A double of a voluntarily bid game or slam often calls for the lead of a specific suit. The idea is not so much to score extra points as to give the defense its best chance for a set. After North-South's auction, a double by East would have asked West to lead the first suit dummy bid - a lead West wouldn't consider otherwise.
East couldn't double if North had jumped to 3NT. Then North might have extra strength, and North-South might have nine top tricks (and North might redouble). In the actual auction, a double by East was mandatory.