I’m halfway through a stay in Japan, the land of the free public toilet. City squares, riverside walks, bus interchanges in the middle of nowhere – chances are there’s one waiting. The grubbiest are old but clean enough. The cleanest are like operating theatres. I think of days in British cities where you have to draw up a dot-to-dot itinerary taking in that Starbucks (customers only); that department store (if it hasn’t closed down); that museum (entry £5).