Old apartments probably built around 1960’s.
A typical rooms in such an apartment is called “4-jou one-roomed apartment” with a small kitchen but without toilet nor bathroom (shower room). “jou” is a classic unit used to express the size of a room and 1 jou corresponds to the area of one Tatami which is 1.6562 m2.
Poor collage students tend to stay in those rooms dreaming of getting out of the place to a new world.