The inventor of this roll is known, and she still lives in Philadelphia. Chef Ai Saito, born in Kobe and trained partly in Paris, known to everyone as Madame Saito, was looking at an American brunch classic in her restaurant in the mid-1980s: smoked salmon and cream cheese on a bagel. That breakfast, shared with a Jewish friend, dropped into her mind the question that changed sushi history: why shouldn’t this pair meet rice and nori?

She presented the new roll to a crowd at a public demonstration. She herself called it the Jewish roll, honoring its inspiration; but the audience kept shouting the city’s name. The roll was named not by its maker but by the crowd: the Philadelphia Roll.

The sweet irony is that the cream cheese is not from Philadelphia either. The cheese was born in 1872 in New York State, in the hands of a dairyman named William Lawrence; its brand took the name of Philadelphia, then famous for fine dairy, as a stroke of marketing. So a two-layered urban legend stands inside this bite’s name.

The silk of the salmon and the cool density of the cheese, though, need no legend. Balance is its own proof.