This is not a map of Tokyo’s subway system, but main line trains. The subway lines are the blue crossed lines contained mostly within the circle of routes at the center right of the map. Just 14 years after World War II’s conclusion, the sheer amount of tracks in just the Tokyo/Yokohama area is astounding. Not the greatest cartography ever, however: the map is a bit of a mess.

Source: Rob Ketcherside/Flickr