New businesses arising to meet new needs tell us much about the times we live in. A cleaning company named Green Heart, for example, thrives on a peculiar expertise. Its website explains: "Sadly, it often happens that unclaimed bodies go long unnoticed. In summer after two days, in winter after four or five, decomposition sets in, accompanied by odors surpassing the imagination." This sort of cleanup is Green Heart's specialty. In the seven years since its founding in 2005, its custom has doubled. It is open 24 hours a day, and hardly a day goes by, it says, without a commission.

Traditional Japanese culture celebrated its hermits — poets and enlightened ones who, awakened to the futility of worldly attachments, cast them off and retired to mountain huts to commune with the infinite. Modern reclusion is different. Neither enlightenment nor poetry figures in it, and it's a moot point whether individuals are casting off the world or the world them. Either way, it's spreading. The average number of people per Tokyo household is 1.99, the Metro government reported last month. In 1957 it was 4.09; in 1966, 2.97. The dip below 2 is a first, and indicates more people living alone than ever before.

Why should "unclaimed bodies go long unnoticed"? Because living alone can mean dying alone. The weekly Josei Jishin takes up the theme, chronicling a cluster of recent deaths that, were the chemistry of decomposition less malodorous than it is, would likely have gone much longer unnoticed than they did. As it happens, the episodes the magazine describes involve people dying not quite alone but in pairs, a reminder that solitude need not be absolute to be grimly isolating.