Mr. Yokota and his twin brother were just 9 when their 13-year-old sister disappeared from coastal Niigata. Mr. Yokota still recalls the day she did not come home from badminton practice, and how they helped their mother search for her as dusk fell.

The Yokotas also met with Ms. Kim in 2010. “She could not say much because she was surrounded by South Korean intelligence and police,” Mr. Yokota said. “But she did tell my mother, ‘She’s all right, and you don’t have to worry.’ ” North Korea maintains Ms. Yokota committed suicide in 1994.

Ms. Kim is somewhat vague about how she knows that either Ms. Taguchi or Ms. Yokota is still alive.

She said the women had probably picked up classified information from working with spies, so it made sense for North Korea to declare them dead.

But, she said, “I do not think they have passed away, because the reasons that North Korea gave for their deaths are not reasonable.”

After Ms. Kim was convicted in the airplane bombing, the Japanese police showed her photos of several women suspected of having been abducted by North Korea. Ms. Kim says she recognized Ms. Taguchi.

Ms. Taguchi’s family did not come forward to the police until 2002, when the prime minister, Mr. Koizumi, went to Pyongyang. Seven years later, when Ms. Taguchi’s son, Koichiro Iizuka, was 32, he and an uncle who had raised him met with Ms. Kim for the first time.

Ms. Kim said that when she met Koichiro, she felt an immediate kinship after having listened to his mother weep for her children. “I almost felt like his mother,” Ms. Kim said.