The 22-year-old Gyong-Hwa, originally from Pyongyang, says she is six months into a three-year work placement in Cambodia. But she will likely see little of the country in which she works, and will return to her homeland with little knowledge of it. Like all North Koreans working abroad, she and her fellow waitresses live highly regimented lives. When asked if she had seen the famous temples of Angkor or been sight-seeing around the capital, she giggled nervously and shook her head. Where does she live? She motioned upwards, indicating the living quarters upstairs from the restaurant, before shuffling off to replenish our half-empty glasses.

Pyongyang Restaurant is one of possibly hundreds of North Korean restaurants that were set up across Asia to raise hard currency after the DPRK's economy took a nose-dive in the mid-1990s. The lives of the women who are sent abroad to work in these establishments are secretive and encapsulate a problem facing the North Korean regime: how to bring in more foreign earnings without allowing their citizens to be "contaminated" by foreign ideas. In mid-February, as a popular uprising broke out in Libya, around 200 North Korean construction workers there were prevented from returning to their homeland. The reason, according to the Yonhap news agency, was to block news of the Arab uprisings from reaching the isolated state.

In the case of the waitresses, managing this balance requires every mechanism of control at the regime's disposal. Experts say the waitresses are overwhelmingly drawn from the uppermost echelon of songbun, the regime's political caste system. Kwon Eun-Kyoung, English editor of the Daily NK, a Seoul-based news organisation dedicated to reporting on the DPRK, said that those sent to work at overseas eateries are likely subject to the same degree of political screening as reserved for staff at Department No. 5 of the Central Committee of the Korean Workers Party, which coordinates Kim Jong-Il's daily activities.

"When they select girls who are working -- even just typists, or women who clean up the buildings -- they always check the whole family background and loyalties, and if they are members of the party or not," she said. "The family backgrounds mean more than three generations, up till their grandfathers." Kwon said the waitresses posted overseas are subject to the same strictures that accompany their high-caste status within the North, which includes daily and weekly "evaluation meetings." "It is a regular routine," she said.

By the standards of North Korea, where debilitating poverty and widespread malnutrition make physical health a handy index of political suitability, the women at Pyongyang Restaurant are especially notable for their height. In her 2010 book Nothing to Envy: Everyday Lives in North Korea, American journalist Barbara Demick writes that residency in Pyongyang -- the showcase capital -- is reserved for the upper rungs of the songbun system. Northern defectors, often from famine-stricken rural areas, are of scrawny stature compared to their privileged brethren from the capital.