by Gayle Mak

Tokyo has one of the densest, if not the densest, subway systems in the world. An estimated two million people a day pass through the city’s main Shinjuku Station—which, with its labyrinth-like network of underground tunnels and shops, is possibly the liveliest in Tokyo.

Taking the chikatetsu, or subway, is a fascinating travel experience in itself. It not only gives you a chance to familiarize yourself with the city’s layout, it also provides the opportunity to explore a parallel underground world that embodies the pulse of Tokyo as much as the city’s above-ground, frenetic buzz.

The chikatetsu easily takes you everywhere you’ll want (or need) to go as a tourist. The trains are prompt, clean, and convenient, and offer, in addition to the advantages of an efficient commute, an intriguing microcosm of Japanese society.

I always find it interesting to observe the behavior of the commuters, from the middle-aged salaryman in his ubiquitous dark suit solemnly poring through his manga, or comic book, to the high-school girl in her sailor-suit uniform effortlessly curling her eyelashes.

The locals rarely stand facing one another on the trains. According to the unwritten rules of Japanese commuting etiquette, if there are no seats available, the locals automatically assemble themselves in two parallel rows, each facing away from the person standing behind him.

On the other hand, Japanese commuters also display an impressive willingness to share—and even sacrifice—personal space on the trains. A row of subway are typically packed elbow-to-elbow during rush hours, with seated passengers routinely and nonchalantly making space for yet another person to squeeze.

It is common to see middle-aged salarymen and well-groomed office ladies sitting semi-perched on the edge of their seats, arms huddled in a protective embrace over their briefcases or shopping bags, so as to take up minimal space. It’s hard to know whether this is a voluntary act of self-sacrifice for the collective good—or simply an instance of Japanese pragmatism.

Whatever the case, Tokyo’s subway is a world in itself, complete with its own rules, quirks, and, of course, an occasional rebel.