On this occasion, however, the stocky customer is the instructor, and the “trainee” has been put through a rigorous day-long test to see if he can perform the job at hand, work in which many of the other staffers - who are referred to in this part of Shinjuku’s Ni-chome district as “boys” - are already well-versed. “He’s here for an interview … and kenshū,” says bar manager Toshiyuki Matsuura, using a Japanese term for “training” that in everyday parlance would do little to raise any eyebrows. 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.