All the big-name Japanese designers are clustered together in this district on the tree-lined Omotesando Boulevard: Yohji Yamamoto, Comme des Garçons, and Issey Miyake and his other labels (Haat and APOC, for A Piece of Cloth), plus interesting younger Japanese labels such as Tsumori Chisato and Frapbois. Look out for Sou-Sou, which sells its own version of the traditional split-toed soft Japanese shoe. Prada's spectacular  glass store, designed by Swiss duo Herzog and De Meuron, is here, too. Tod's, Gucci, Louis Vuitton, and others are wall-to-wall, and they're housed in buildings by native architects whose names are bigger here than Marc Jacobs. Tadao Ando's 366,000-square-foot development, Omotesando Hills, opened in February 2006 and is a minimalist's fantasy mall, housing brands such as Yves Saint Laurent and Dolce & Gabbana. Unlike Tokyo's much larger luxury malls, which can be overwhelming, Omotesando Hills feels exclusive and manageable in both its gorgeous design and its choice offerings. Go on a weekday evening to avoid the weekend crowds; you'll have the entire place to yourself.

Tokyo's art scene is scattered throughout the city, and the galleries come in all shapes and sizes, from the colossal Tokyo National Museum in Ueno Park to the modernist Mori Art Museum in Roppongi to the Ota Memorial Museum of Art in Harajuku. For a snapshot of what's new and happening in the oddball world of Tokyo art, go to the harbor-front Kiyosumi neighborhood in Koto-ku, a 10- to 15-minute cab ride from Ginza. You'll find a cluster of some of Tokyo's best contemporary galleries in a converted warehouse at 1-3-2 Kiyosumi: Tomio Koyama (81-3-3642-4090; www.tomiokoyamagallery.com), Taka Ishii (81-3-5646-6050; www.takaishiigallery.com), and Shugo Arts (81-3-5621-6434; www.shugoarts.com/en/index.html). Koyama's artists include two of Japan's current stars, Takashi Murakami and Yoshitomo Nara, while Taka Ishii represents Nobuyoshi Araki, who has been photographing the underside of Tokyo for decades. Closer to Kayabacho station and the nearby financial district, you will find the prewar Inoue Building at 2-7-13 Nihonbashi-Kayabacho, which houses Masataka Hayakawa (81-3-5649-6369; www.masatakahayakawa.co.jp) and Taguchi Fine Arts (81-3-5652-3660; www.taguchifineart.com). Tokyo's Museum of Contemporary Art isn't far away, at 4-1-1 Miyoshi in Koto-ku, where Japanese and international art is showcased with a refined sense of whimsy (www.mot-art-museum.jp/english).

The celebrated Japanese architect Fumihiko Maki has been adding to his Hillside Terrace development here for more than three decades. Today, this smart residential neighborhood is also filling up with fashion boutiques and cafes. Residents include the Danish Embassy and Yamada Heiando, suppliers of lacquerware to the royal family. Be sure to explore the backstreets to find interesting shops like Onitsuka Tiger for sneakers, APC, Bonjour Records, and the bag shop B Yoshida.

This complex is less a museum than a whole day out. Earthquakes, firebombing, and rampant development have left few examples of old architecture in Tokyo, but in 1993 the Tokyo government set aside about 17 acres for this collection of historic buildings, which range from farmhouses and soy sauce shops to private homes and public bathhouses. They were all saved from demolition and relocated to this fascinating outpost of the central Edo-Tokyo museum. Among the highlights: the home of much-admired Modernist architect Kunio Mayekawa.

Long the haunt of ladies who lunch, take in a show at the Kabuki theater, and shop in the big department stores and genteel back streets, Ginza has suddenly become hip. While it's always boasted some of Tokyo's most exclusive clubs and Japanese restaurants, it's now also home to an increasing number of the city's finest French (Brasserie Paul Bocuse) and Italian (La Bettola da Ochiai) restaurants, and even tapas bars. The famous Sony Building and its electronics showroom now compete with an Apple store. There's a Barneys, flagships of famous labels such as Hermès and Dior, and the Chanel Ginza Building, which is topped by Alain Ducasse's restaurant Beige. Don't miss the Mikimoto Ginza 2 store: Designed by Toyo Ito (he was also behind the arresting Tod's store in Omotesando) with irregular windows and a central atrium, it is dazzling—and is fittingly home to Dazzle, a jaw-dropping restaurant and bar that's a good spot for evening drinks.

If the relentless concrete and expressways get to be too much, take a short walk from Shiodome station to historic Hamarikyu Garden. Originally built in the 17th century for a feudal lord, it served as the first shogun's official duck-hunting ground and later became the residence of Ienobu, the sixth shogun, in 1704. Today the garden is an unexpected pocket of greenery, with beautiful pines, a large tidal pond, and two duck-hunting fields (unused, these days). The teahouse serves traditional green tea and Japanese sweets. The new skyscraper district of Shiodome now towers over the garden, providing what the Japanese refer to tactfully as "borrowed scenery."

On weekends, this district of street fashion is crowded with wildly dressed kids who congregate near the entrance to the beautiful Meiji Shrine. Expect goths, cybergeishas, and "Lolitas" in mini-crinis. Rockers—top-to-toe in black and sporting serious hairdos—gather at the entrance to Yoyogi Park and dance for hours on end, even in the searing summer heat. The main drag is Takeshita Dori, a road that slopes down from the park and is lined with a carnival of teeny bopper boutiques. The backstreets—a.k.a. Urahara—are where the sneaker, T-shirt, and street-fashion stores are found, as well as the trippy Design Fiesta, an artist collective with a great Bohemian café. Cool off there with a beer after experiencing the Harajuku bedlam. (3-20-18 Jingumae; 81-3-3479-1442; www.designfesta.com/index_en.html).

Opened in 1979, this private contemporary art museum is set in the former home of the Hara family. The house itself is very unusual, a Bauhaus-inspired structure built in 1938. The permanent collection takes in a broad range of international and Japanese artists, and there is a rotating schedule of first-rate exhibitions. Extensions have been built by the Japanese architect Arata Isozaki, and the small cafe-restaurant looks onto the garden.

Closed Mondays.

Leave the bedlam of Harajuku behind and walk to Meiji Shrine, a peaceful, wooded haven dedicated to Emperor Meiji (1852–1912). Pass through the giant cypress gate (or torii) at the back of Harajuku Station and walk along the wide gravel path. The shrine is an impressive sight—austere wooden buildings surrounded by greenery. On a quiet afternoon it can feel a long way from Tokyo. Meiji Jingu is a popular place to get married; on the weekends you're likely to see a wedding party in traditional outfits.

Japan is famous for its rustic hot springs (onsen), and even Tokyo has its own mineral-rich baths. Azabu-Juban Onsen sits above a natural source whose dark waters are said to be good for all sorts of complaints, including poor circulation and sensitive skin (81-3-3404-2610; 1-5-22 Azabu-juban, Minato-ku; closed Tues). Soak in the old-style tiled baths and then relax with a beer and a plate of edamame soybeans. Alternatively, pay a visit to one of Tokyo's historic sento or public bathhouses. Built in the days when few houses had their own bathroom, their numbers are now sadly dwindling. One of the best is Daikokuyu, which has all the classic sento elements: spotlessly clean showers and baths for soaking (segregated for men and women) and giant murals of Mount Fuji (81-3-3881-3001; 32-6 Sento-kotobukicho, Adachi-ku). The etiquette is simple: Shower before getting into the bath, and once in the water, absolutely no soap, swimsuits, or washing of clothes!

This contemporary art museum sits on the 53rd floor of the Mori Tower in Roppongi Hills. It has large, stylish spaces and an ambitious exhibition program with a strong emphasis on contemporary Asian art. Unlike other museums in Tokyo, it's open seven days a week and late into the evening. A single ticket buys entry to the museum and also to the Tokyo City View platform on the 52nd floor—a great place to check out the Eiffel-esque Tokyo Tower and the elegant Rainbow Bridge.

Nakameguro, a spillover district from fashion-centric Daikanyama, has been dubbed the new hip hangout by trend-conscious Tokyoites, although it's far quieter and more subdued than its neighbor. There's a good stretch of Euro-focused retail and culinary opportunities along the tree-shaded Meguro River, a popular stroll during cherry blossom season in early April. Look out for some unusual boutiques and art galleries upriver from the subway station, plus one-offs like the alternative bookshop Cow Books (81-3-5459-1747; www.cowbooks.jp/english.html). Downriver, the bookish riverside café Combine is alone worth a visit; it's a great place for a midday glass of sake or a café au lait (81-3-3760-3939; www.combine.jp).

A wonderful museum devoted to mingei or folk art, the Nihon Mingei-kan was founded by scholar Soetsu Yanagi in 1936. The mingei movement highlighted the beauty of simple, regional crafts that were in danger of being lost in the thrust for modernization. It was started by Yanagi and his friends, the potters Bernard Leach, Hamada Shoji, and Kawai Kanjiro. A visit to the museum's traditional wooden building is a treat, removed as it is from the noise of nearby Shibuya. The collection includes ceramics and textiles and other handcrafted objects from all over Japan as well as items from China, Korea, the United States, and European countries.

Closed Mondays.

This tatami-floored museum (you must wear slippers inside) has one of Japan's best collections of ukiyo-e woodblock prints and offers a respite from the crowds of Harajuku. Founder Seizo Ota collected thousands of works, and all the best-known artists, including Hokusai and Hiroshige, are represented. Leave your shoes in a locker by the entrance and enjoy the peace and quiet. There's an interesting shop in the basement that sells hand-printed Japanese cloths called tenugui.

Closed Mondays.

The pink portals of the Almond Coffee shop, a landmark for decades, mark the epicenter of the infamous nightlife district you either love or loathe. Sweaty bars with names like Gas Panic, Geronimo's, and Castillo's, plus salsa clubs, hostess bars, and Irish pubs, have long attracted a motley and rowdy mix that included international models and American military personnel. But now Roppongi is polishing its reputation and attracting a new crowd to two gigantic multiuse developments that have sprung up right across the street from each other: Roppongi Hills, a dizzying indoor-outdoor collection of boutiques, restaurants, galleries, and cinemas, and the humongous Tokyo Midtown luxury mall, which most locals claim makes Roppongi Hills yesterday's news. The only solution is to go check them both out for yourself.

Tokyo's oldest temple is said to have originated in 628 when fishermen found a small gold statue of Kannon in their nets. Senso-ji, or Asakusa Kannon, as it's also known, is now one of Tokyo's most popular sights. Pass through the famous red gates (Kaminarimon) and walk up Nakamise Street along a row of small shops selling everything from tourist trinkets to traditional crafts. The temple itself is bustling with activity, particularly on festival days; on New Year's Day, the place is mobbed with hundreds of thousands of worshippers praying for good luck in the year to come. The temple was destroyed by firebombing in 1945, and the main hall (Hondo) was rebuilt in 1958. To the right of Senso-ji is the Shinto shrine Asakusa-jinja, which somehow has survived bombs and earthquakes and dates to 1649. To get to Senso-ji, either take a boat up the Sumida River from Hinode Pier or take the Ginza or Asakusa subway lines to Asakusa station.

The crossing in front of Shibuya station—one of the busiest intersections in the world—is a sight in itself, with thousands of pedestrians and huge video screens blaring the latest J-pop. Shibuya is where locals come to get lost in the hilly maze of restaurants, shops, bars, clubs, and gaming parlors. This is the gathering place for Tokyo's kogyaru—girls with dyed hair, deep tans, and boyfriends to match—as well as uniformed schoolkids and salarymen out for a night on the town. Head past the video-screen towers, under the neon arches, and downhill into the winding streets—uphill is mostly residential, as well as a less frenetic location for hotels such as the Granbell Shibuya.

Shinjuku is a metropolis-within-a-megalopolis, an elevated neighborhood on top of the world's busiest station and Tokyo's western hub. This is modern Tokyo at its most unapologetic: a fast-paced, neon-branded, mind-boggling labyrinth of shops, high-rise malls, and clubs (some of which are a bit dodgy). Take a wrong turn and you could easily end up in edgy Kabuki-cho, the red-light district, the black-suited yakuza men outside clubs named Vanity or Goddess are a sure sign that you've strayed into Tokyo's darker side. The high-rise area around Nishi (West) Shinjuku is where you'll find the cathedral-like headquarters of the Tokyo government and one of the city's best hotels, the Park Hyatt. But the modern quickly fades to the grit and back-alley vibe of early postwar Tokyo in Golden Gai, which houses a warren of cubbyhole bars for live music and light snacks. Tokyo's gay district, Shinjuku Ni-Chome, has a decidedly international flair, with Euro-centric bars and clubs, as well as the legendary jazz favorite Pit Inn. Shinjuku also has one of Tokyo's most impressive public parks, Shinjuku Gyoen, which is a favorite during cherry-blossom season in early April and well worth the small entrance fee.

As any resident will tell you, Tokyo is nothing like the rest of Japan, and since you're on the island, you really should take a train journey into the verdant hills and mountains just outside the metropolis. The beauty of the city's location is that within an hour on a train, you could be climbing 1,500-foot mountains, wending your way through the foliage in search of hidden Buddhist shrines, or eating noodles by the lush, ferny riverside on a breezy day. The two-hour trip to either Kyoto or Nikko is worth it. If not, there are closer destinations, such as the resort town of Hakone and the temple-clustered Kamakura, both about an hour away.

Sumo wrestling is one of the quintessential Japanese sports, and there are three tournaments a year in Tokyo, all held at the sumo stadium in Ryogoku. Matches begin with the lower ranks and end with the top wrestlers. The best seats are in boxes of four (on tatami mats), although it will be hard to find a seat anywhere near the ring (or dohyo) on the day. Sumo is a hierarchical, traditional sport and rituals are strictly adhered to; even the waitstaff runs around delivering food and drinks in anachronistic garb. Bouts are short and tense, and crowds respond to well-fought matches by throwing their cushions in the air. Join the fans afterward and watch the supersize wrestlers leave the stadium in their cotton robes (yukata) and wooden shoes (geta). The Ryogoku area is brimming with historic sumo connections—there are numerous sumo stables in the area and many restaurants serving the chanko-nabe stew that wrestlers eat to bulk up. Consult the Sumo Association website for schedules and ticket information.

Does Tokyo's latest shopping, working, living, dining, and entertainment complex, which includes this earthquake-prone city's tallest building, the Midtown Tower (814 feet), relegate Roppongi Hills to "yesterday's destination"? Greenery-deprived and mall-loving locals, who relish Tokyo Midtown's cherry tree–dotted (and Wi-Fi accessible) grassy parks, seem to think so. Built in the heart of Roppongi on the site of the former Defense Agency, this is a great rainy-day destination. Check out the complex's art galleries, museums, and chic boutiques, or just wander and people-watch. With dozens of eateries, including Coppola's Vinoteca, which features wines from the film director's Napa vineyard (Tokyo Midtown Garden Terrace 2F, Akasaka 9-7-5; 81-3-5647-8301), and an outpost of New York's own Union Square Café, you'll never go hungry (Tokyo Midtown Garden Terrace 9-7-4, Akasaka Minato-ku; 81-3-5413-7780; www.unionsquarecafe.com). Better yet, book a suite at the complex's new Ritz-Carlton Tokyo (Akasaka 9-7-1, Minato-ku; 81-3-3423-8000; www.ritzcarlton.com/en/Properties/Tokyo). And if you decide you want to stay forever, the hotel also has luxury residences.

Open daily 11 am to 10 pm.

The national museum of Japan has a spectacular collection of Japanese art, but the displays can be on the old-fashioned side. One exception is the Horyuji Treasure House, a beautiful new building designed by Yoshio Taniguchi (the architect who remodeled the Museum of Modern Art in New York) to display the outstanding treasures of Horyuji Temple in Nara, one of the most important temples in Japan. The National Museum is located in Ueno Park, home to a clutch of top museums and Tokyo's Festival Hall.

Closed Mondays.

The best time to visit the world's largest fish market is at dawn, when most of the action takes place. (On your first day in Tokyo, your walloping jet lag will surely wake you before the sun comes up, anyway.) Tsukiji covers an area of over two million square feet and handles more than 2,000 tons of fish every day. Don't be shy about wandering the narrow, inner lanes, where fish flown in daily from around the world is displayed and haggled over. But watch your back and keep moving: This is a serious place of business, and sellers and buyers—and scooters and motorized dollies—move fast and furiously. (Spectators were briefly banned from the exciting tuna auctions because they were getting in the way—currently the tuna auction is off-limits except from 5am to 6:15am). If you oversleep, don't despair; the outer market is a great place to buy everything you'll need to prepare a Japanese feast in your own kitchen (check out the beautiful knives!), plus traditional woven baskets for hauling your purchases home. And of course, there are great (if basic) sushi restaurants there for a late breakfast, such as Sushi Dai, guaranteed the freshest you'll ever eat (81-3-3547-6797).

Open Mondays through Saturdays 5 am to 2 pm.

Ueno is the old-fashioned part of town that's popular with visitors who come for its cultural attractions. Several museums (including the Tokyo National Museum) and the Festival Hall are clustered in Ueno Park, which is also home to Japan's oldest zoo and Toshogu Shrine. The park has more than 1,000 cherry trees and is a popular spot for spring cherry blossom viewing. Ueno is close to Akihabara, also known as Electric Town, which is the place to go for the latest gadgets and electronics.

Yanaka and its neighbors, Sendagi and Nezu, still retain something of the flavor of prewar Tokyo and make up the core of shitamachi, Tokyo's old downtown. Walk from Sendagi Station to Yanaka Ginza, a bustling shopping street selling everything from Japanese sweets to garden supplies. Yanaka highlights include the late sculptor Fumio Asakura's beautiful house, studio, and garden (81-3-3821-4549; 7-18-10 Yanaka, Taito-ku; closed Mon and Fri), SCAI the Bathhouse, a contemporary gallery space in a converted public bathhouse (81-3-3821-1144; Kashiwayu-Ato, 6-1-23 Yanaka, Taito-ku; www.scaithebathhouse.com; closed Sun and Mon), plus plant-filled side streets and numerous neighborhood temples like Keio-ji. Finish up with a stroll through leafy Yanaka cemetery.