The nagaya were inexpensive wooden row houses built on narrow plots of land; they constituted the basic type of urban rented structure in Tokyo. Figure 2 shows the layout of a typical nagaya, Built around a well communal toilet (the proximity of water supply and sewage system was a major factor in the spread of cholera and other contagious diseases), nagaya normally composed of two or more building with separate roofs set on either side of a sewage ditch, each of which was subdivided into several rooms.