PRAGUE — Marta Kubisova sat in a small back room of the cafe at the Lucerna Cinema, pulled a skinny cigarette from a silver case and rattled a long strand of pearls as she remembered the Velvet Revolution.

“The young today do not really know what happened then,” she said. “But that is natural, I suppose. For me, it was a resurrection. For them, it is something in the history books.”

Twenty-five years ago, in the full force of the uprising against Communism, Ms. Kubisova, now 72, was thrust onto a balcony overlooking a teeming Wenceslas Square by her friend Vaclav Havel and asked to perform an a cappella rendition of her most famous song, “Prayer for Marta.”

It was that 1968 pop hit, whose lyrics express gentle yearning for a nation’s self-determination, that led the Communist authorities to ban her in 1970, making that impromptu concert above Wenceslas Square her first public performance in nearly 20 years.