"The North Korean economy was one of the most demonetised, the most tightly controlled, government planned economies of the 20th century," he said.
They have been dubbed the "Jangmadang Generation" in a nod to the markets that taught them how to be entrepreneurial in the face of oppression.It's the lunchtime rush at a restaurant just outside the South Korean capital, Seoul, and Ms Ju is scurrying from the kitchen to tables as she serves dishes to hungry customers.
Ms Ju's father was the first one to make the dangerous trip across the border to China in 2008, followed by her mother and younger brother a year later. Ms Ju believes her entrepreneurial spirit was forged during the years she spent working at the Jangmadang markets."In South Korea, people seem to live in a fear of breaking a stable life or safe job. I like to be adventurous and try new things, and I think it's all because of my past."Even if I fail, I can think 'Ah, it was fun,'" she said.Park Yo Sep was in third grade when the famine struck, and forced him to grow up quickly.