There is no sign on the little restaurant’s front door. Inside, the austere, whitewashed room seats only 42 people. And night after night, you will find the proprietor himself, Sotohiro Kosugi, bent behind his sushi bar with his two loyal assistants, working with a kind of surgeon’s intensity in his spectacles and white sushi cap. Kosugi is a third-generation sushi chef, from a small town in northern Japan that he likes to say “has more fish than people.” For eleven years, he labored in Atlanta, where his cooking won a wide following among diners in that sushi-starved region