The BBC in October published a glowing encomium to Japanese cleanliness. "How," it asks, "does Japan stay so clean?"

It's deeply ingrained, the report explains. Shinto purifies the body, Buddhism cleanses the mind, the tea ceremony sweeps the last speck of dust from the rustic tea hut. Heir to all this is the modern classroom, which children end every school day by cleaning, to the bemused admiration of non-Japanese worldwide.

So clean a country ought to be happier. The U.N.'s World Happiness Report ranks Japan 58th this year, suggesting something deeply wrong somewhere. Tadashi Yanai, Japan's richest man and founder and president of Fast Retailing, famous especially for its clothing chain Uniqlo, looks bleakly into the future. "Japan is going extinct," he told Nikkei Business magazine last month.