News of a North Korean nuclear testreached the rest of the world in short order, but days after the rogue nation claimed it tested a hydrogen bomb, 17-year-old Jinwoo Ha, in neighboring South Korea, said she hadn't heard.

"Mmmmm, sorry, but I don't quite know about the issue, so can you please explain that?" she said, after being asked for her reaction to the test.

She and several of her peers south of the border say they have more pressing matters on their minds.

"We have to study, we have to live, we have to work," said Kim Hyejun, a 21-year-old art student. When asked how often she thinks about North Korea, she said, "Just that they are there, we are here, that's all. We don't have family out there, we don't talk, we can't see them. To me, it's another country."

Older generations may remember a once-unified Korea and what tore it apart, but that was decades ago.

"The young people, they don't have a history of the Cold War and of communism and of the ideological fight," says Katharine Moon, SK-Korea Foundation chair at the Brookings Institution.

And North Korean nuclear rhetoric has always been in the background of their lives.

"These are individuals who have grown up with multiple annoucements and declarations about the North's threatening postures and programs. So in a way, they've become very familiar with this narrative," Moon says.

They also haven't felt tangible consequences, such as the effects of radiation leakage or worse, actual war.

There is one constituency among younger generations that is watching North Korea more closely: college-age South Korean men, for whom military service is mandatory.

"We're very concerned because we have to go in [the] military," says Jeong-kyu Lee, who completed his mandatory service but fears being called back in the event of combat. "If North Korea does some ... bombs, we like, all have to like, prepare for war, right?"

Sure, the possibility exists, but it has for so long that it's had a desensitizing effect. Domestic concerns here, like high youth unemployment, can cause far more worry than the threat of a bomb.

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