Musician Koshi Inaba finds himself in completely new terrain on a Wednesday afternoon in early September. The 60-year-old artist has performed in venues, arenas and festival grounds across the country, as a solo act or part of the best-selling Japanese musical group of all time, B’z. Yet on this day, tucked in the corner of the eighth floor of NHK’s offices in Shibuya Ward, he smiles as he scans his stage.

“An office,” he says with a chuckle midway through his one-take performance as part of the national broadcaster’s Tiny Desk Concerts Japan. More than 200 employees — including everyone from NHK’s entertainment department — laugh with him before a round of applause. Six camera operators are capturing the show as it happens, one balancing on a row of desks.

Inaba, joined by four backing musicians, performs a rollicking near-30-minute set. Before the performance starts, executive producer Tetsuya Shibasaki addresses the employees gathered to watch. “It’s like a concert today,” he says, imploring them to be excited and clap between songs (but keep phones off for fear of ringing).