It is believed that the expression was coined by the students of Keio University, who were coming to Ginza for a cup of Brazilian coffee, another new trend at the time. So they probably made Gin-bura from "Ginza de Brazil coffee". Another theory is that the term comes from Ginza and burabura, which means strolling, hanging around.
Anyway, Gin-bura remained until today a popular pastime, and it is best experienced during weekends and public holidays, when Ginza becomes a pedestrian paradise.
EXIF info:
Nikon Df
Lens: 24-70mm F/2.8G
Focal Length: 24mm
Aperture: F/3.5
Shutter Speed: 1/400s
ISO Sensitivity: ISO 500