The Senior Life Master had returned from Canada, where he had gone to see the fall colors. He was now sitting in the club bar, sipping on a glass of Australian semillon.
"How was your trip?" his neighbor asked. "Did you play any bridge?"
"I had a great time, thank you. The polychromatic leaves on the trees were spectacular. And, yes, I did play some bridge. Let me show you an interesting defensive deal."
After writing out the West and North hands on the back of a coaster, the SLM continued.
South opened one weak no-trump, showing 12-14 points. Many Canadian pairs still use the English Acol system, including a weak no-trump and four-card majors. North trotted out Stayman, then jumped to four hearts. You lead the spade ace: four, two, three. What would you do now?
After a few moments, the SLM's companion seemed to have spotted the answer, so the SLM hurried to explain.
Since it is unlikely that declarer has five spades and East queen-doubleton, you should place South with the spade queen. So you should shift, and it is logical to lead the diamond seven at trick two, the high card denying an honor. You hope that partner has the ace as an immediate entry and pushes a spade back through declarer's queen.
Note that this is the only way to defeat the contract. If you switch to a club, declarer wins with the nine on the board, plays a club to his king, draws trumps ending on the board, runs the clubs, and plays a diamond through East to take three hearts, one diamond, four clubs and one ruff in each hand.