Wander around and watch the sights or lie back and wait for someone who fancies you, instructs one guide, which blissfully advises customers to expect 'some mind-blowing tableaus'. Soak in the sauna/bathtub then make your way up semi-naked through the floors, where porn flickers 24 hours a day in dimmed communal sleeping areas equipped with futons. Past the ticket machine – 2,600 yen (about £18) for a 13-hour stay – and pretty much anything goes, say guests who come from across Japan, and even abroad, to sample its treats. Only in the lobby, cheerily adorned with scenes from a sex movie that depict a portly company president being diligently serviced by a young apprentice, does it become clear that this is one of Asia's biggest gay landmarks.
A steady stream of customers in the salary-man's uniform of dark suit, sensible shoes and winter overcoat files quietly through its innocuous doors. Tucked in off a back-street near the Shinjuku business and shopping district, the seven-story building could be an apartment block for retired civil servants. Nothing outside Tokyo's 24 Kaikan hotel hints at what goes on behind its grey concrete walls.
