At a glance, First Dash is just a regular Tokyo bar. Customers laugh and drink, their animated chatter competing with the monotonous beat of techno thumping through speakers hovering somewhere above dimmed, orange-tinted lights.

When a customer enters, however, a row of eight fresh-faced young men who had previously been gathered around the bar counter glued to their smartphones suddenly rise to their feet and in unison bark out a well-rehearsed greeting: "Irasshaimase!"

The customer — a portly, balding middle-aged man in a nondescript suit — shuffles over to a table followed by a slightly built teenage lad, ruffled locks partly shielding a furtive, floor-fixed stare.