how better to sample the Sturm und Drang of the planet's busiest metropolis than on its most famous train? The Yamanote Line loops overland around the buzzing heart of Tokyo, stopping at many of its biggest attractions. One of the transport wonders of the world, its brisk, frictionless efficiency should be on any list of Japan's best, most inexpensive pleasures.
The train is the great leveller, drawing in all walks of Tokyo life. In the morning, it fills with the pensive energy of the city's huge, dark-suited workforce, as the equivalent of almost half of London's population fills its carriages. After the housewives, pensioners and schoolchildren, the workers are back in the evening, ties undone, jackets off, beery breaths filling the carriages.
There are 29 pit stops aboard the Yamanote's distinctive green carriages. Start at the world's busiest station, Shinjuku, then head two stops to Harajuku and walk along the youth mecca of Omotesando, Asia's premier shopping boulevard, where goths, Lolitas, rockers and young fashionistas populate a shopping landscape crowded with boutiques and brand franchises.
Seventeen minutes further up the line to Sugamo, and you cross the city's generation gap, as the river of human traffic turns greyer and slower as it files past shops selling thermal underwear, hearing aids, orthopaedic socks. Shop fronts have been modified to accommodate wheelchairs, and hand-written signs replace neon.
Back on the train to Tokyo Station and walk the short distance to the Imperial Palace. One of the capital's few architectural constants, the palace is effectively and fittingly the centre of the Yamanote loop, dominating the heart of Tokyo, forcing traffic and trains to detour around it. The central link to Japan's mythologised past, the reclusive family behind the moat claims an unbroken heritage dating back 2,600 years; silently marvel at how they have survived earthquakes, fascism, US fire-bombing, constitutional revolution and a succession crisis, all in the 20th century.
After checking out Meiji Shrine (japan-guide.com/e/ e3002.html), head for Akihabara. Sandwiched between the staid book-selling district of Kanda and Ueno Park, this was once the core of Japan's electronics retailing industry, but has become a sort of nerd's paradise, selling anime characters, videogames and toys.
Tokyo has failed for years to reach a government-set annual target of 10 million visitors. Too far, too hot and too expensive are the most common complaints from potential tourists – but it's also hampered by its image as a colourless bunker city of worker bees, too uptight to compete with freewheeling Asian rivals such as Bangkok or Hong Kong. Those perceptions are wrong.
Japan's capital has always known how to let down its hair unobtrusively. It may also be the world's safest major city and is served by probably its cleanest, most efficient transport system. Tourists are spoilt rotten, tipping is verboten and for good measure it has been crowned the world's culinary capital. What's not to like?
I suggest ending your exploration of the city back at Shinjuku, and another short walk to the Park Hyatt, where Scarlett Johansson and Bill Murray wallowed in luxurious alienation in Lost in Translation. There you can savour the startling views from the hotel's New York Bar, including the thin line of the Yamanote as it ferries its human cargo into the night.
David McNeill is Tokyo correspondent of The Independent