It was still dark outside when the sound of murmuring engines and fishermen testing marine radios awakened the small harbor of Daejin on South Korea’s east coast. Park Cheol-hoon and his father loaded their three-meter-long boat, the Cheongjinho, with nets and spears, then set out to catch seafood for their family restaurant. Their destination: waters perilously close to North Korea, the place they fled 18 years before.

Every day, dozens of South Korean ships set sail for the Jeodo fishing grounds despite the risks of being just one mile from the DPRK. Vessels are a broken radar or engine away from accidentally drifting across an invisible border into North Korean waters, and perhaps also into the hands of the regime.