A curved Turkish saber? Yataghan. Faulkner’s fictional county? Yoknapatawpha. A musical by Irving Berlin, three words? Yip Yap Yaphank.

You don’t hear these words every day. But Dad has explained their value. Lots of vowels, certain infrequently-found consonants. They make the puzzle come together. And I am likely to encounter them again, in future Double-Crostics.

My father and I sit on the living room sofa in our Kew Gardens apartment, holding a spiral-bound book of Kingsley Double-Crostics between us, working on the exotic species of puzzle to which he’s recently introduced me. I am ten, near-sighted, good at spelling. Since second grade there has been a large callous on my right middle finger from my habit of gripping a pencil very hard. Dad is forty-five, a World War II veteran. In the army, he was given an exam that qualified him to serve in “the intelligence.” He became a code-breaker, a cryptanalyst, part of a team stationed secretly in a barn in North Dakota: a story I love to hear. The town didn’t even know soldiers were there. He won’t say much more, says he mustn’t even now.

Now he works as an accountant, at the same company for many years, which doesn’t sound too exciting. But he’s kept his love of puzzles and shared it with me. He has tips, secrets, arcane facts at his fingertips. His patience, perseverance, and a seemingly bottomless fund of knowledge have me in awe.

A Double-Crostic isn’t solved without some sweat. You’ve got to figure out all the answers and transfer their letters as you go, in scrambled order, into a numbered grid. Finally the grid reveals a passage, and the first letters of each answer, in sequence, spell the name of its author and the title of its source. When most of the puzzle has begun to give way, my father always declares with satisfaction, “You’ve cracked it!”–reminding me of the tough codes he helped to break.

Today the author is Virginia Woolf, the work “A Room Of One’s Own.” We read a passage that compares women to mirrors “reflecting the figure of man at twice its natural size.” My father laughs hard at that. Another day, we read from Richard Burton’s autobiography. Burton has grown tired of parties, he explains, where people stare at him as if he were “a prize animal.” I never forget these passages.

Time and again, Dad and I share the work of figuring out the answers, copying their letters painstakingly into the grid and arriving together at a chance to read something funny or clever or profound. Better than any Cracker Jack prize, I think.

I stay stuck on puzzles over the years, not just the Double-Crostic but all varieties of crossword: the saucy “puns and anagrams”; the confounding “diagramless” that gradually reveals its contours; even, in a pinch, the conventional type. I look forward each month to the cryptic puzzles at the back of Harper’s magazine and the Atlantic Monthly. When I visit my parents, who have retired to Connecticut, I wait for the moment Dad will hand me the latest New York Times Magazine puzzle page, a red pen, and ask me to “finish this up” for him. I’ll feign dismay: “What made you put in this answer?” while making the few corrections to his copy. A tradition.

Now I am as old as Dad was when he first enlisted me in puzzle-solving. These days I tackle the daily Financial Times crossword, a cryptic variety so loaded with Britishisms that some days I might as well be guessing at a foreign language. If I falter, there’s an excuse. This is a private love, I think, not easily shared with anyone, especially now that Dad is gone.

One day, I ride the train home from a visit with my mother. I stare down idly at the newspaper in my lap, folded open to the crossword for which I have little appetite today. Suddenly the woman next to me clears her throat, and I look up. She smiles, her eyes aglow. “I used to work on those,” she offers, “a long time ago.” Has she tired of them too? No, she means something else. She asks if I’ve heard of Eugene Maleska, the late New York Times puzzle editor. Of course. “Well, I was his assistant. He was just wonderful,” she says.

I think of my father’s old spiral-bound book of double-crostics, containing our two sets of handwriting. “You can crack it,” he would say. And I turn back now to today’s puzzle with renewed interest, and begin to read the clues.