The difference between eating in the handsome main dining room and at the intime, six-seat chef's counter, hidden in the back of this Dupont Circle Japanese restaurant, comes down to a lot of money and rare detail. Put yourself in the hands of chef-owner Nobu Yamazaki for an evening, and not only is the sake poured into cups of your own choosing and the wasabi grated before your eyes, but the lessons flow nonstop: Whole fried river trout is pleasantly bitter because the tiny fish feeds on algae, the master tells us. The fine noodles in a glass bowl of eel, smoked eggplant and clear broth are tinted pale green with tea, he offers. The lid of what looks like a brick is lifted to reveal matchsticks made from dried sea cucumber roe ("Seafood jerky!" cries my pal) and a dip of squid ink, sake and chili pepper. Intriguing. Less luscious: the one-note edamame soup with fried okra and a sardine cake. There are two house-made soy sauces; they come with a small brush for dabbing the sushi, some of the raw fish for which is bought at Tokyo's famed Isukiji market. "I feel like I've been to Japan," my companion whispers as we reluctantly depart one of the most enchanting meals in the city that doesn't require a passport. Having just dined on some of the most exquisite food in Washington -- and having tucked $400 into the bill holder for the privilege -- I can only nod and sigh.