The JR Chūō Main Line, marked in dependable blue on transit maps, arcs westward from Tokyo Station to Nagoya. To the east, the Sōbu Main Line, also shaded in a similar blue, extends to Chōshi, a coastal city on the fringes of Chiba Prefecture, just beyond the bounds of Greater Tokyo. 

Within Tokyo, two distinct services run along these trunk lines: the yellow Chūō-Sōbu Line and the bold orange Chūō Rapid Line. The Rapid Line begins its eastbound journey from Takao, in Hachiōji City, and terminates at Tokyo Station. The Chūō-Sōbu Line stretches from Mitaka in the west to Chiba in the east.

From Mitaka, the two services run side by side on a quadruple-track corridor. At Ochanomizu, their paths diverge as the Rapid Line turns south toward Tokyo Station, while the Chūō-Sōbu Line continues east. Along this shared stretch between Mitaka and Ochanomizu, the Chūō-Sōbu stops at every station, designating it the “Local”.

Together, the Chūō Rapid and Local Lines, with their combined stretch of approximately 94 kilometres, form a vital spine through the Tokyo Metropolis. I’m currently midway through a self-initiated undertaking to walk their entire length, from Takao to Chiba.

This week’s newsletter comes to you from Ryōgoku—reached on foot after a four-day stretch covering 56 kilometres and passing 33 train stations. I’ve now crossed the halfway point, and the experience has been all-encompassing.

At the end of each day’s walk, I return to my room, feet aching, and write the nightly Field Notes newsletter. It captures that day’s impressions: neighbourhood highlights, coffee stops, and moments of urban reflection. If you'd like to follow along, you're welcome to join midway. At the journey’s end, I’ll compile an archive of the full series, along with a complete itinerary and map.

Ahead lie three more days and 38 kilometres on foot, though, so it’s best not to get ahead of myself. For now, I’ve chosen three columns from Field Notes so far to share with you.