The Tokugawa set about creating a city befitting their new status. By 1640 Edo Castle was the most imposing in all Japan, complete with a five-storey central keep, a double moat and a spiralling network of canals. Instead of perimeter walls, however, there were simple barrier gates and a bewildering warren of narrow, tortuous lanes, sudden dead-ends and unbridged canals to snare unwelcome intruders. Drainage work began on the surrounding marshes, and embankments were raised to guard the nascent city against floods.

The shogun protected himself further by requiring the daimyo to split the year between Edo, where their families were kept as virtual hostages, and their provincial feudal holdings. This left them with neither the time nor the money to raise a serious threat, but the daimyo were compensated with large plots on the higher ground to the west of the castle, an area that became known as Yamanote . Artisans, merchants and others at the bottom of the pile were confined to Shitamachi , a low-lying, overcrowded region to the east. By the mid-eighteenth century, Edo's population was well over one million, making it the world's largest city, of whom roughly half were squeezed into Shitamachi at an astonishing 70,000 people per square kilometre. Though growing less distinct, this division between the "high" and "low" city is still apparent today.

During the long period of peace, the shogunate and its beneficiaries grew ever more conservative, but life down in the Shitamachi buzzed with a wealthy merchant class and a vigorous, often bawdy, subculture. This is the world most closely associated with Edo, the world of geisha and Kabuki, of summer days on the Sumida-gawa, moon-viewing parties and picnics under the spring blossom - fleeting moments captured in ukiyo-e , pictures of the floating world. Inevitably, there was also squalor, poverty and violence, as well as frequent fires; in January 1657, the Fire of the Long Sleeves laid waste to three-quarters of the city's buildings and killed an estimated 100,000 people.

By the early nineteenth century the Tokugawa regime had become increasingly weak and isolated. When they failed to confront Commodore Perry, the American who insolently sailed his Black Ships into Edo Bay in 1853, the days of the shogunate were numbered, and ended with the Meiji Restoration in 1868. The following year Emperor Meiji took up permanent residence in the city, now renamed Tokyo (Eastern Capital) in recognition of its proper status.

As Meiji Japan embraced the new, Western technologies, the face of Tokyo gradually changed: the castle lost its outer gates and much of its grounds; canals were filled in or built over; the commercial focus shifted south into Ginza, and Shitamachi's wealthier merchants decamped to more desirable Yamanote. However, the city was still disaster-prone; the Great Kanto Earthquake of 1923 devastated half of Tokyo, and another 100,000 people lost their lives.

More trauma was to come during World War II . In just three days of sustained incendiary bombing in March 1945, hundreds of thousands were killed and great swathes of the city burnt down, including Meiji-jingu, Senso-ji, Edo Castle and most of Shitamachi. From a prewar population of nearly seven million, Tokyo was reduced to around three million people in a state of near-starvation. This time regeneration was fuelled by an influx of American dollars and food aid under the Allied Occupation, and a manufacturing boom sparked by the Korean War in 1950.

Political tensions erupted in the capital in May 1960 , when rioting broke out over ratification of the revised Security Pact . The crisis passed, though student discontent continued to rumble for a long time and riot police became a familiar sight on the streets. On October 10, 1964, however, Emperor Hirohito opened the Tokyo Olympic Games , and visitors were wowed by the stunning new Shinkansen trains running south to Osaka.

The booming economy of the late 1980s saw Tokyo land prices reach dizzying heights, matched by excesses of every conceivable sort, from gold-wrapped sushi to mink toilet-seat covers. The heady optimism was reflected in the building projects of the time - the Metropolitan Government offices in Shinjuku, the Odaiba reclamation and the vast new development of Makuhari Messe. Then, in 1991, the bubble burst. This, along with revelations of political corruption, financial mismanagement and the release of deadly Sarin gas on Tokyo commuter trains by the AUM cult in 1995 - a particularly shocking event in what is one of the world's safest cities - led to a more sober Tokyo in the late 1990s. While the new millennium has brought the glimmerings of an economic recovery, they are tempered by a growing list of spectacular business failures, higher unemployment and a general sense of unease - not that you'll notice much on the streets. New buildings continue to go up at a dizzying speed, teen fashions are wilder and funkier than ever, and the Tokyo buzz is as addictive as ever.