SEOUL, South Korea — On a sidewalk in central Seoul recently, Lee Mi-il and several other older South Koreans took turns at a microphone, calling out what seemed like an endless list of names. They began in the morning and continued through the night, announcing one name after another — 83,000 in all — their voices ringing out and melting into the cacophony of the city’s busiest district.

A few young pedestrians paused at this unusual demonstration. But most paid little attention.

The scene could have been a metaphor for Ms. Lee’s struggle of more than a decade.

Since 2000, Ms. Lee has campaigned to generate more interest in the fate of tens of thousands of South Koreans believed to have been forcibly taken to North Korea during the Korean War six decades ago. She has been demanding that the government negotiate for the return of those who may still be alive and the remains of those who are not. Government officials have never made that issue a priority when they have sat down with their North Korean counterparts, treating her campaign as a distraction from what they consider a more important task: persuading the North to abandon its nuclear weapons.

But Ms. Lee, 62, is not giving up, and recently she has scored some victories against what she calls “a gigantic darkness and forgetfulness.”