Tokyo's markets provide a vital counterpoint to the museums and monuments of conventional sightseeing: they let you see how people really live in the city. If you have time for only one market, this is the one to see. The three square blocks between the Tokyo Central Wholesale Market and Harumi-dori have, naturally enough, scores of fishmongers, but also shops and restaurants. Stores sell pickles, tea, crackers and snacks, cutlery (what better place to pick up a professional sushi knife?), baskets, and kitchenware. Hole-in-the-wall sushi bars here have set menus ranging from ¥1,000 to ¥2,100; look for the plastic models of food in glass cases out front. The area includes the row of little counter restaurants, barely more than street stalls, under the arcade along the east side of Shin-Ohashi-dori, each with its specialty. If you haven't had breakfast by this point in your walk, stop at Segawa for maguro donburi—a bowl of fresh raw tuna slices served over rice and garnished with bits of dried seaweed (Segawa is in the middle of the arcade, but without any distinguishing features or English signage; your best bet is to ask someone). Some 100 of the small retailers and restaurants in this area are members of the Tsukiji Meiten-kai (Association of Notable Shops), and promote themselves by selling illustrated maps of the area for ¥50; the maps are all in Japanese, but with proper frames they make great souvenirs.
Visit the Travel Talk forums for help on planning your trip