A boyfriend I had at university in Tokyo once told me that older teammates from his sports club had taken him to a sex parlour. So I was not surprised to learn that 48% of Japanese men have paid for sex at some point, compared with 11% of British men. In Japan the industry is woven into male social life—but it has rarely been the subject of serious debate, and the laws governing it are murky.

This year, though, sex work became a political issue. The trigger was a rise in street prostitution around a park in Tokyo. It stands out in a country where most of the trade happens behind closed doors. Nor has it helped that many of the men approaching these women are foreign tourists taking advantage of a weak yen. For some Japanese men—even those who think nothing of buying sex themselves—that stings their pride. In the booming 1970s and 80s, it was Japanese men who flew abroad for it.