Dinner at Crab 52 starts with clam chowder and a plate of steamed snow crab, but for the next half-hour it's all about the raw bar. That 30-minute window matters. The main dishes begin circulating roughly 30 to 40 minutes after service begins, and once the butter and chili sauces arrive, the appetite for raw fish tends not to return. The restaurant, billed as the most expensive buffet in the country, occupies the 52nd floor of Trade Tower in Gangnam, Seoul, with sightlines running to the Han Riv