Liu Jing, 32, is visiting Seoul from China’s eastern seaboard. Other tourists might spend their day taking in the capital’s sights. Not Liu. She’s lining up behind at least a dozen compatriots in a duty-free shop, waiting her turn to buy JM Solution facial sheet masks. Each box of ten will cost her about $30, but Liu won’t walk away with just one. For the equivalent of $18,000, she and the others buy three refrigerator-size palettes of carts—so big they have to be wheeled away on dollies. This is the latest article is in a new series: World of Forbes, a collection of stories from our 35 licensed editions and global partners around the planet. This story originally appeared in the July-August issue of Forbes Asia. Liu isn’t buying them for herself. She’s a daigou—a Chinese term for surrogate buyers who venture abroad to stock up on popular products and resell them back home. To say JM Solution masks are popular is an understatement. Between the Honey Luminous Royal Propolis Mask, the Lacto Saccharomyces Golden Rice Mask, and the Active Pink Snail Brightening Mask, JM Solution’s owner, GP Club, has sold more than a billion skin-care masks, mostly in China, since launching them in ...