Detail of central Tokyo from the National Library of Australia: “City map, central Tokyo / prepared under the direction of the Engineer, GHQ, FEC ; by the 64th Engineer Base Topographic Battalion” (1948). See: Map of American occupied Tokyo, 1948 GHQ東京占領地図
If you zoom in you’ll notice a network of canals in the Ginza neighborhood. These were largely filled-in after the war, which I describe here: Canals of the Ginza: floating through time on Tokyo’s central waterways 東京江戸「水の都」