There is a way of knowing a city that only comes from running through it. The Tokyo Marathon, one of the six World Marathon Majors, gives more than thirty thousand runners that particular knowledge across a single Sunday in early March.

The course begins in front of the Metropolitan Government towers in Shinjuku and stitches its way through the city — past the Kaminarimon gate at Asakusa, past the Imperial Palace, past Tokyo Tower — 42.195 kilometers that link the landmarks not by subway map but by the body's own effort. To run it is to learn the real distances between places you thought you knew, to feel the city as a continuous thing rather than a set of stations.

Along the route stands a wall of spectators, hundreds of thousands deep, calling out to strangers, holding up names. Elite runners chasing world times and ordinary citizens who trained for a year share exactly the same road — one of the quiet democracies of the marathon.

It falls in early March, on a Sunday still edged with cold, just before the city's spring. For that one day, Tokyo belongs to the runners. The great machine of the metropolis pauses and opens its avenues, and the city is traced not on paper but through the legs and lungs of the people moving across it.