In a serene, plant-filled studio paneled with large windows, Kim Do-yoon gives tattoos to clients who visit him in South Korea from around the world for his fine line work. A diaphanous octopus with its tentacles unfurled, a delicate wildflower sweeping over a forearm, a portrait of a beloved pet to last forever.

Kim, known as Doy, is a favorite of celebrities, including actor Brad Pitt and actress Han Ye-seul, but he works discreetly.

There is no sign advertising his studio, nestled in a nondescript building in north-central Seoul, near a palace that dates back to the 14th century. He screens customers carefully, rolls the blinds down during appointments and moves his shop about every two years.