Like many of the top sushi chefs in the U.S., New York City--based Nick Kim buys fish from a company called True World Foods. "They know exactly what we're looking for. If you can close your eyes and picture anything from Tsukiji market [the legendary Tokyo marine emporium], they can get it for you," Kim says. "It's a great personal relationship."
Personal? By all accounts, True World is one of the largest--if not the largest--suppliers of fish to sushi restaurants across the U.S. Yet it is a mysterious company, one whose exact dimensions are unknown, whose own employees can't identify its...