I walked into the club lounge and observed Cy the Cynic and Ed Fitch, the ophthalmologist who presides over our club, engaged in earnest conversation. After a while, Cy got up and left to play in his penny Chicago game.
"Cy wants me to surreptitiously switch Minnie's glasses," Ed told me. "I said that would be medically unethical, and Cy said it was medically necessary to keep him from losing his sanity."
Minnie Bottoms, my club's senior member, wears old bifocals that make her mix up kings and jacks, often to her opponents' dismay. Cy has been Minnie's chief victim.
"He showed me the latest deal," Ed nodded.
The Cynic was South, declarer at four spades doubled, and Minnie sat East. When West led the jack of hearts against Cy's game, dummy played low, and Minnie took the ace and shifted to - the jack of diamonds!
"Cy took dummy's king and called for a trump," Ed told me, "but Minnie insisted that it was still her lead."
"She thought she had the A-K of diamonds," I laughed. "She was cashing out her four top tricks."
"After they got it sorted out," Ed said, "Minnie won the second trump and led another diamond, and West won with the queen and returned a heart. Minnie ruffed for down one."
Minnie and her eyeglasses found the only winning defense. East must create an entry to the West hand to get a heart ruff, and the queen of diamonds is the only entry West can have.