Nihonbashi was the center of Edo, former name of Tokyo, during Edo period (1600-1867) and everything including culture and rich and people following them gathered at this place.
Nowadays, Nihonbashi is still holds a role as one of the centers of Tokyo, and some of the department stores hold head shop in Nihonbashi.
The picture shows a main street of Nihonbashi with Mitsukoshi head shop.