Like the Denver Broncos, the Nikkei stock index and "Gravity" director Alfonso Cuarón, Japanese food is on a hot streak. Here at home, the revival of interest in classic regional fare known as B-kyū gourmet (B-level cuisine) has spread to supermarket shelves and fast-food menus around the country. Overseas, everyone from the casual restaurant-goer to the head of the U.N.'s cultural agency has been lavishing unprecedented levels of attention and praise on washoku.